Performance of Low- and High-Chill Peach Cultivars in Tropical Highland Environments: Impacts on Yield, Phenology, and Fruit Quality

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This study evaluated chilling requirements, phenology, growth, yield, and fruit quality of ten peach ( Prunus persica L) cultivars under tropical mild-winter conditions using the Dynamic Model (Chill Portions, CP), with Chill Hours and Utah Chill Units as references. Low-chill cultivars (8–18 CP; Earlygrand, Flordadown, Tropicsnow ) consistently exhibited synchronized flowering, high bloom density (≥ 75%), vigorous vegetative growth, stable yields (16–20 kg/tree), and superior fruit quality. Intermediate-chill cultivars (18–26 CP) showed partial dormancy release and variable productivity, while high-chill cultivars (30–38 CP; Transvalia, Springcrust, Novadonna ) displayed delayed phenology, poor bud break, restricted growth, low yield (1–2.5 kg/tree), and high variability. Strong negative correlations between CP and vegetative growth (r = − 0.88 to − 0.91) and yield (r = − 0.90 to − 0.92) validate the Dynamic Model’s physiological relevance in tropical climates. These findings provide actionable guidance: low-chill cultivars are optimal for consistent flowering, robust growth, and high-quality fruit production in tropical mild-winter regions, whereas intermediate- and high-chill cultivars require careful evaluation or are unsuitable. Cultivar-specific chilling assessment is essential for optimizing peach performance in tropical production systems. Peach tropical mild winters chilling requirement Dynamic Model phenology yield fruit quality Figures Figure 1 Figure 2 Highlights • Peach performance in the Ethiopian highlands is strongly determined by chilling requirements, vegetative growth, and flowering phenology. • Low-chill cultivars exhibited early, synchronized flowering, stable fruit set, and high yields under limited winter chill. • High-chill cultivars showed delayed flowering, poor fruit set, and low yields, indicating limited suitability for mild-winter environments. • Targeted selection of low-chill, fast-growing, and early-flowering cultivars is critical for sustainable peach production in tropical highlands. 1. Introduction Peach ( Prunus persica L .) is a major temperate fruit crop with broad adaptability; however, its successful cultivation depends on sufficient winter chill to ensure uniform dormancy release, synchronized flowering, and reliable fruit set (Faust and Surányi, 2008 ). In tropical and subtropical highland regions, including parts of East Africa, winter temperatures are often too mild to satisfy the chilling requirements of many high-chill cultivars, resulting in delayed or erratic budbreak, reduced bloom intensity, poor fruit set, and unstable yields (Liu et al., 2016 ; Gole and Radeny, 2021 ). As global warming continues to reduce winter chill, identifying cultivars suited to warm-winter environments has become increasingly important (Sato and Nakamura, 2020 ). Although low-chill peach cultivars have been successfully cultivated in subtropical regions (McGee, 2000 ; Topp et al., 2012 ), their phenology, vegetative performance, and fruit quality under tropical highland conditions remain insufficiently documented (Lu et al., 2012 ; Toumi et al., 2023 ). In Ethiopia, peach production has expanded in the central highlands due to favorable agro-climatic conditions and increasing market demand; however, introduced cultivars have shown inconsistent performance, largely due to mismatches between their chilling requirements and local chill accumulation (Gole and Radeny, 2021 ). Systematic assessments integrating chilling compatibility with field-based performance metrics are therefore needed to guide cultivar selection and management. Chilling accumulation commonly estimated using models such as the Dynamic Model is a critical determinant of dormancy release and flowering synchrony in peaches and other deciduous fruit species (Faust and Surányi, 2008 ). When chill is insufficient, flowering becomes sparse and asynchronous, undermining pollination success and yield stability (Liu et al., 2016 ). Recent studies highlight that low-chill genotypes may provide more reliable performance where mild winters limit the productivity of high-chill cultivars (Sato and Nakamura, 2020 ). Additional stressors such as recurring droughts and pest pressure both increasingly relevant in tropical highlands further emphasize the need for multi-trait evaluation (Gole and Radeny, 2021 ). Given these constraints, identifying peach genotypes capable of thriving in mild-winter tropical highlands is essential for sustainable orchard development. This study evaluates ten peach cultivars differing in chilling requirements to: (i) relate local chill accumulation to cultivar-specific phenology; (ii) assess vegetative growth, flowering behavior, yield, and fruit physical and chemical quality; and (iii) analyze correlations among key agronomic traits. The findings aim to support evidence-based cultivar recommendations and orchard management strategies to optimize peach production in tropical highland environments. 2. Methodology 2.1. Study Location The experiment was conducted at the Holetta Agricultural Research Center (Fig. 1 ) in the central Ethiopian highlands (≈ 2,400 m a.s.l.). The site has a temperate highland climate characterized by mild winters and moderate summer temperatures. Long-term climate data (Table 1 , Fig. 2 ) indicate a mean annual temperature of 15–25°C, with minimum winter temperatures occasionally reaching ~ 10°C (NMI, 2024). These relatively warm winter conditions result in limited chill accumulation, making the site representative of low-chill production environments. Annual rainfall ranges from 800–1,200 mm, concentrated primarily in the June–September rainy season, while the October–May period remains comparatively dry. Relative humidity averages 65–85% during the wet season and remains moderate throughout the year due to altitude and supplemental irrigation. The orchard soil is a well-drained clay-loam with 2–4% organic matter and a slightly acidic pH (6.0–6.5), suitable for peach cultivation. Table 1 Monthly Mean Climate for Holetta (1980–2024); located at central Ethiopian Highlands (2400 m a.s.l.) Month Mean T min (°C) Mean T max (°C) Rainfall (mm) Rel. Humidity (%) Jan 6.5 22.0 8 50 Feb 7.0 23.0 12 48 Mar 8.0 24.0 35 52 Apr 9.5 23.5 75 60 May 10.0 22.5 110 65 Jun 10.5 21.5 185 75 Jul 10.0 20.5 280 85 Aug 10.0 20.8 255 84 Sep 9.5 22.5 140 70 Oct 8.5 23.0 35 60 Nov 7.0 22.5 10 55 Dec 6.0 21.8 5 50 Note : Annual Rainfall: ~1,150 mm; Annual Mean Temperature: ~15.0°C; Dry Season: Oct–Feb; Main Rainy (Kiremt) Season: Jun–Sep; Short Rains (Belg): Mar–May Source (National meteorology Institute (NMI) 2024 . 2.2. Plant Materials Ten peach cultivars introduced to Ethiopia were evaluated. Planting material was sourced from Viveros Oreros Nursery (Spain), a certified global supplier of disease-free stone fruit seedlings. The cultivars included: Earlygrand, Flordadown, Bonnigold, Flordastar, Tropicsnow, Summersun, Transvalia, Springcrust, Maycrust , and Novadonna . At the time of evaluation, trees were 10 years old and grafted onto the GF 677 (peach × almond) rootstock, chosen for its strong vigor, drought tolerance, and resistance to soil-borne pathogens such as Phytophthora and Verticillium . All trees were maintained under uniform orchard management. 2.3. Chill Accumulation Assessment Chilling requirements of peach cultivars were estimated using the Dynamic Model, expressed as Chill Portions (CP), which is widely regarded as the most physiologically robust method for quantifying effective winter chill under mild, fluctuating, and warm winter temperature regimes (Fishman et al., 1987 ; Erez et al., 1990 ; Campoy et al., 2011 ). Hourly air temperatures (Tₕ) during dormancy were used to accumulate chill, where chill accrues through a two-step process, and seasonal chill was expressed as: CP = Σ Δ CP_d (d = 1 to n), with Δ CP_d, the daily increment and n the dormancy period. Cultivar chilling requirements were defined as the minimum CP consistently associated with uniform bud swell and synchronized flowering (Faust and Erez, 1995 ; Byrne et al., 2012 ). Cultivar-specific chilling thresholds were inferred from multi-season observations of uniform bud swell, flowering synchrony, and bloom density, indicators commonly used to assess dormancy release and chilling adequacy in peach (Faust and Erez, 1995 ; Byrne et al., 2012 ). For comparison, Chill Hours (CH) and Utah Chill Units (CU) were also derived as: CH = Σ I(Tₕ ≤ 7.2°C) (h = 1 to H) and CU = Σ w(Tₕ) (h = 1 to H), where I is an indicator function and w(Tₕ) is the Utah Model temperature weight; but chilling adequacy and cultivar adaptation were interpreted primarily from CP values. These indices were not used as primary indicators of chilling adequacy, as both models are known to overestimate effective chilling under tropical and subtropical conditions, where winter temperatures frequently fluctuate above optimal chilling ranges and warm nights may negate accumulated chill (Erez et al., 1990 ; Luedeling, 2012 ). Consequently, CH and CU values were considered approximate reference indices only, whereas cultivar classification and interpretation of adaptation were based primarily on CP values derived from the Dynamic Model. Cultivars were classified into very low-, low-, moderate-, and high-chill categories according to CP thresholds consistent with observed phenological performance under tropical mild-winter conditions rather than catalog-based chilling requirements derived from temperate environments. This phenology-based classification approach provides a more realistic assessment of cultivar suitability for peach production in warm winter regions and aligns with current recommendations for dormancy evaluation under climate-limited chilling scenarios (Campoy et al., 2011 ; Luedeling et al., 2009 ). Observed chill accumulation was compared with published cultivar CR benchmarks to classify cultivars as either chill-compatible or chill-limited (Kwon, et al., 2020 ), that served as reference thresholds for evaluating local climatic suitability and potential dormancy satisfaction. To facilitate comparison with established literature, the results were compared to match benchmark reporting formats widely used in subtropical and warm-climate peach research (Kwon et al., 2020 ). Heat requirements were discussed in parallel, acknowledging that the relationship between chilling and heat accumulation is cultivar-specific rather than directly convertible (Pope et al., 2014 ). This classification supports evaluating cultivar suitability for tropical highland environments, where cool nighttime temperatures allow partial chill accumulation but warm daytime conditions may interrupt or negate chilling progression, often reducing the effectiveness of traditional chill models. 2.4. Experimental Design and Observations The study was conducted using a randomized complete block design (RCBD) to evaluate the performance of multiple peach cultivars under tropical highland conditions. Each cultivar was represented in three replications, with three trees per replication arranged at a spacing of 6 m × 5 m, ensuring uniformity and minimizing competition effects. Observations were conducted over three consecutive growing seasons (2020–2022) to capture inter-annual variation. Phenological events were recorded using Julian day (DOY) to maintain alignment with international standards and enable precise temporal comparisons across years and cultivars, as dates of key phenological stages such as beginning of bloom and end of bloom are routinely expressed on the day-of-year scale in peach phenology research (e.g., beginning of bloom, full bloom and end of bloom expressed as JD/DOY) (Drogoudi et al., 2023 ; Atagul et al., 2022 ). 2.4.1. Vegetative and Phenological Traits Vegetative growth was assessed through measurements of tree height, canopy spread, and tree volume (m³), providing an integrative view of tree architecture, as commonly applied in recent plant structural trait research (Li et al., 2025 ). Tree Volume (V) = (4/3) × π × (H/2) × (CS₁/2) × (CS₂/2) Where: H = tree height (m) CS 1 , CS 2 ​ = two perpendicular canopy spread measurements (m) Annual vegetative vigor was quantified by recording shoot growth (cm), while leaf area (cm²) measurements allowed assessment of photosynthetic capacity and canopy density, consistent with current approaches linking leaf area metrics to canopy function (Peano et al., 2025 ). Shoot Growth (SG) = L final - L initial Where: L final and L initial​ are shoot lengths at the end and start of the growing season, respectively. Leaf Area (LA) = N × A leaf Where: N = number of leaves sampled A leaf ​ = average leaf area per leaf (cm²) Phenological development was monitored by documenting key reproductive stages, including bud swell, pink bud, full bloom, and petal fall, with additional observations on the duration and density of bloom to characterize flowering intensity and synchronicity across cultivars, following standardized phenology characterization frameworks that describe seasonal vegetation transitions such as budburst and leaf emergence (Cui et al., 2025 ). Bloom Density (%) = (Number of open flowers / Total potential flowers) × 100 Flowering Duration = Date of petal fall - Date of bud swell 2.4.2. Yield and Yield Stability Fruit production was quantified at multiple levels. Fruit number per tree and yield per tree (kg) were recorded, providing basic measures of productivity. To normalize for tree size, yield efficiency was calculated as the ratio of yield to tree volume. Total productivity at the orchard scale was estimated by calculating yield per hectare, assuming a planting density of 625 trees/ha. Temporal stability of yield was evaluated using two complementary metrics: the coefficient of variation (CV) to quantify relative variability across seasons, and the deviation from the mean (DM) to assess year-to-year departures from average performance, thus providing insight into cultivar reliability under fluctuating climatic conditions. Phenological events in the trial were expressed using Julian day (day of year, DOY) to maintain alignment with international standards and enable precise temporal comparisons across years and cultivars, following recent peach phenology research where key stages including ripening and maturity dates are quantified in DOY for cross-seasonal analysis (Pietrella et al., 2025 ; Verma et al., 2023 ) 2.4.3. Fruit Physical and Chemical Quality Fruit quality assessments encompassed both physical and chemical attributes (Petruccelli et al., 2023 ). Physical characteristics measured included fruit weight, volume, diameter, and length-to-diameter (L/D) ratio, as well as stone weight and pulp-to-stone ratio, which collectively inform marketable yield and consumer preference. Firmness was quantified using a penetrometer to assess postharvest handling potential. Chemical composition analyses included total soluble solids (TSS, °Brix) measured with a refractometer, titratable acidity (TA, % citric acid equivalent), and the TSS/TA ratio, a critical indicator of fruit taste balance. Further, sugar composition was determined via the Anthrone method for total sugars (measured at 620 nm), reducing sugars using the DNS method (540 nm), and non-reducing sugars calculated by difference. Finally, ascorbic acid content was quantified using DCPIP titration, providing insight into the nutritional quality of the fruit. 2.5. Statistical Analysis All collected data were subjected to analysis of variance (ANOVA) to test for statistically significant differences among cultivars for each measured trait, with the significance threshold set at p < 0.05 (Montgomery, 2020 ). For traits where the ANOVA indicated significant differences, Tukey’s Honest Significant Difference (HSD) test was employed for multiple mean comparisons, providing robust pairwise differentiation while controlling for Type I error (Montgomery, 2020 ). The use of Least Significant Difference (LSD) tests was intentionally avoided due to its higher propensity for Type I errors under multiple comparisons (Zar, 2010 ). To investigate the relationships among vegetative, phenological, yield, and fruit quality traits, Pearson correlation coefficients were calculated, offering insights into linear associations between key variables (Zar, 2010 ). All statistical analyses were conducted using SPSS version 26 for standard ANOVA and correlation procedures, while R software with the “chillR” package was used specifically for chill accumulation calculations and related temperature-based analyses (Luedeling et al., 2009 ; Luedeling, 2018 ). 3. Results 3.1. Chilling Requirements of Peach Cultivars under Mild Tropical Winters Table 2 presents the estimated chilling requirements of selected peach cultivars evaluated under tropical mild-winter conditions using the Dynamic Model (Chill Portions, CP) as the primary metric. Comparative Chill Hours (CH) and Utah Chill Units (CU) are included solely for reference. The Dynamic Model is widely recognized as the most physiologically relevant method for assessing chilling adequacy in warm and fluctuating winter climates, outperforming traditional CH and CU models, which frequently overestimate chilling accumulation due to their inability to account for chill negation and the reduced effectiveness of warm temperature exposure. Consequently, CH and CU values in the table should be interpreted only as approximate reference indices rather than direct physiological equivalents. Table 2 Estimated chilling requirements of peach cultivars under tropical mild-winter conditions using the Dynamic Model, with comparative Chill Hours and Utah Chill Units provided for reference only. Cultivar Dynamic Model (Chill Portions, CP) Chill Hours (CH)† Utah Chill Units (CU)† Adaptation under Tropical Mild Winters Earlygrand 8–12 ~ 60–120 ~ 80–120 Very low chill; consistently adapted Flordadown 12–18 ~ 120–220 ~ 100–180 Low chill; stable flowering Bonnigold 18–22 ~ 180–300 ~ 160–240 Moderately adapted; risk in warm winters Flordastar 18–22 ~ 180–300 ~ 160–240 Similar response to Bonnigold Tropicsnow 22–26 ~ 220–360 ~ 180–260 Borderline; CH/CU tend to overestimate Summersun 25–30 ~ 280–420 ~ 240–340 Marginal; inconsistent bud break Transvalia 30–35 ~ 350–500 ~ 300–400 High risk without dormancy manipulation Springcrust 30–35 ~ 350–500 ~ 300–400 Poorly adapted to tropical winters Maycrust 18–22 ~ 200–320 ~ 180–260 Often overestimated in catalog values Novadonna 30–35 ~ 380–520 ~ 320–420 Unsuitable in most tropical locations Note: † Chill Hours (CH) and Utah Chill Units (CU) are included solely for cross-model comparison. These models are known to overestimate effective chilling under tropical and subtropical temperature regimes due to frequent warm night temperatures and fluctuating winter conditions. Consequently, Chill Portions (Dynamic Model) are considered the most physiologically reliable metric for assessing chilling adequacy in mild-winter environments. Values represent estimated chilling thresholds inferred from multi-season phenological response, not catalog classifications derived from temperate regions. As illustrated, cultivars such as Earlygrand, Flordadown and Tropicsnow display very low to low chilling requirements (8–18 CP), showing consistent adaptation and stable flowering under tropical mild winters. Intermediate cultivars like Bonnigold , Flordastar , and Maycrust (18–22 CP) exhibit moderate adaptation, with some risk of incomplete dormancy release during warmer winters. In contrast, high-chill cultivars ( Transvalia , Springcrust , Novadonna ; 30–35 CP) are poorly adapted, showing inconsistent bud break and high risk of dormancy failure in tropical conditions. Notably, several cultivars categorized as “high chill” in temperate climates demonstrate substantially lower effective chilling requirements when evaluated with the Dynamic Model in tropical and subtropical environments, highlighting the importance of region-specific assessment. The CH and CU values are provided only for cross-model comparison and are known to overestimate chilling under tropical conditions. All chilling thresholds are derived from multi-season phenological observations rather than temperate-region catalog classifications. 3.2. Flowering phenology and bloom characteristics Significant cultivar-dependent differences ( P ≤ 0.05) were observed in flowering phenology and bloom characteristics under tropical mild-winter conditions (Table 3 ). Bud swell occurred earliest in Earlygrand (DOY 60) and Flordadown (DOY 62), while Maycrust and Novadonna exhibited the latest dormancy release (DOY 80). Full bloom spanned a 25-day window, occurring between DOY 70 and 95, indicating a broad range of phenological responses among cultivars under limited chilling conditions. Flowering duration increased progressively with delayed phenology, ranging from 25 days in early cultivars to 30 days in late cultivars. However, extended flowering duration did not correspond to improved bloom intensity. Early- and mid-flowering cultivars ( Earlygrand , Flordadown , Bonnigold ) exhibited significantly higher bloom density (≥ 75%) compared with late-flowering cultivars ( Maycrust and Novadonna ), which showed markedly reduced bloom density (~ 30%). Table 3 Flowering phenology, bloom characteristics, and chilling accumulation of peach cultivars under tropical mild-winter conditions. Cultivar Bud Swell (DOY) Pink Bud (DOY) Full Bloom (DOY) Petal Fall (DOY) Flowering Duration† (days) Bloom Density‡ (%) Chill Portions (CP) Earlygrand 60 ± 1.2 a 65 ± 1.0 a 70 ± 1.1 a 85 ± 1.4 a 25 ± 1.3 c 85 ± 3.2 a 22 Flordadown 62 ± 1.1 ab 67 ± 1.2 ab 72 ± 1.3 ab 87 ± 1.5 ab 25 ± 1.4 c 80 ± 3.5 ab 23 Bonnigold 64 ± 1.3 b 69 ± 1.4 b 75 ± 1.5 b 90 ± 1.7 b 26 ± 1.5 bc 75 ± 3.1 b 25 Flordastar 67 ± 1.4 c 72 ± 1.5 c 78 ± 1.6 c 93 ± 1.8 c 26 ± 1.6 bc 70 ± 2.9 bc 27 Tropicsnow 67 ± 1.2 c 72 ± 1.3 c 79 ± 1.4 c 95 ± 1.9 c 28 ± 1.7 b 72 ± 3.0 bc 28 Summersun 72 ± 1.5 d 77 ± 1.6 d 83 ± 1.7 d 100 ± 2.0 d 28 ± 1.8 b 60 ± 2.7 cd 30 Transvalia 75 ± 1.6 e 80 ± 1.7 e 86 ± 1.8 e 103 ± 2.1 de 28 ± 1.9 b 55 ± 2.5 de 32 Springcrust 75 ± 1.7 e 80 ± 1.8 e 88 ± 1.9 e 105 ± 2.2 e 30 ± 2.0 a 50 ± 2.3 e 34 Maycrust 80 ± 1.8 f 85 ± 1.9 f 92 ± 2.0 f 110 ± 2.3 f 30 ± 2.1 a 30 ± 2.1 f 36 Novadonna 80 ± 1.9 f 90 ± 2.0 g 95 ± 2.1 g 110 ± 2.4 f 30 ± 2.2 a 30 ± 2.0 f 38 LSD (0.05) 2.6 2.8 3.0 3.5 2.4 6.5 — Notes : † Flowering duration calculated as the number of days between bud swell and petal fall. ‡ Bloom density determined as the percentage of flowering buds relative to total buds on tagged branches. Values represent mean ± standard error (SE) of three seasons and five trees per cultivar. Different letters within columns indicate significant differences at P ≤ 0.05 according to LSD test. Chill portion accumulation during the dormant season ranged from 22 to 38 CP and was insufficient to fully satisfy the chilling requirements of high-chill cultivars. Cultivars requiring ≤ 25 CP demonstrated synchronized flowering and higher bloom density, whereas cultivars requiring ≥ 34 CP showed delayed phenology, prolonged flowering duration, and incomplete bud break. These results indicate that bloom density and flowering uniformity were more strongly influenced by chilling adequacy than by flowering duration alone, highlighting the importance of cultivar-specific chilling adaptation for peach production under tropical mild-winter environments. 3.3. Vegetative Growth and Leaf Traits of Peach Cultivars in Mild Tropical Winters Table 4 summarizes the vegetative performance of ten peach cultivars under tropical mild-winter conditions. All values are presented as mean ± standard deviation based on measurements of five replicate trees per cultivar. Tree height, girth, spread, and volume declined progressively with increasing chilling requirement (Dynamic Model CP), highlighting a strong negative correlation between CP and vegetative growth parameters (girth: r = − 0.91; height: r = − 0.88; annual shoot growth: r = − 0.89; p < 0.01). Leaf area was measured on fully expanded mature leaves at mid-shoot positions, and represents individual leaf area, averaged over ten leaves per tree. Low-chill cultivars ( Earlygrand , Flordadown ) exhibited vigorous vegetative growth (height 4.5–5.5 m, girth 30–35 cm, annual shoot growth 40–60 cm, leaf area 30–45 cm²), while high-chill cultivars ( Novadonna , Maycrust , Springcrust ) were significantly smaller (height 2.3–3.2 m, girth 16–20 cm, shoot growth 15–35 cm, leaf area 12–28 cm²). This pattern corroborates the Dynamic Model chilling thresholds, demonstrating that cultivars with inadequate chilling show restricted dormancy release, limited bud break, and suppressed vegetative development under tropical mild winters. Table 4 Vegetative growth and leaf characteristics of peach cultivars under tropical mild-winter conditions. Values are mean ± SD (n = 5 trees per cultivar). Leaf area represents individual fully expanded leaves at mid-shoot positions. Correlation coefficients (r) with Chill Portions (CP) are provided to highlight the relationship between chilling requirement and growth performance. Variety CP (Dynamic Model) Scion Girth (cm) Tree Height (m) Tree Spread (m) Tree Volume (m³) Leaf Area (cm²) Annual Shoot Growth (cm) Earlygrand 8–12 32.5 ± 2.1 5.0 ± 0.4 4.8 ± 0.3 10.0 ± 1.2 37.5 ± 5.0 50 ± 6 Flordadown 12–18 31.0 ± 2.0 4.8 ± 0.4 4.5 ± 0.3 9.0 ± 1.1 35.5 ± 5.0 48 ± 5 Bonnigold 18–22 28.5 ± 2.1 4.5 ± 0.4 4.3 ± 0.3 8.0 ± 1.0 33.0 ± 4.8 45 ± 5 Flordastar 18–22 27.0 ± 2.0 4.2 ± 0.3 4.1 ± 0.3 7.0 ± 0.9 31.0 ± 4.5 40 ± 5 Tropicsnow 22–26 26.0 ± 2.0 4.0 ± 0.3 3.9 ± 0.3 6.5 ± 0.8 29.0 ± 4.2 38 ± 5 Summersun 25–30 24.5 ± 1.8 3.8 ± 0.3 3.7 ± 0.2 5.5 ± 0.7 27.5 ± 4.0 35 ± 5 Transvalia 30–35 23.5 ± 1.8 3.5 ± 0.3 3.4 ± 0.2 5.0 ± 0.6 25.0 ± 3.8 32 ± 5 Springcrust 30–35 22.0 ± 1.5 3.3 ± 0.3 3.2 ± 0.2 4.5 ± 0.5 23.5 ± 3.5 30 ± 5 Maycrust 18–22 20.0 ± 1.5 3.0 ± 0.3 2.95 ± 0.2 4.0 ± 0.5 21.5 ± 3.5 28 ± 5 Novadonna 30–35 18.0 ± 1.5 2.8 ± 0.3 2.65 ± 0.2 3.0 ± 0.4 18.5 ± 3.0 25 ± 5 Correlation with CP (Dynamic Model): Scion Girth: r = − 0.91 Tree Height: r = − 0.88 Tree Spread: r = − 0.86 Tree Volume: r = − 0.90 Leaf Area: r = − 0.89 Annual Shoot Growth: r = − 0.89 (p < 0.01 for all correlations) 3.4. Yield Performance and Efficiency of Peach Cultivars under Tropical Mild Winters Table 5 summarizes the mean yield and yield efficiency of ten peach cultivars evaluated over three consecutive seasons under tropical mild-winter conditions. Values are presented as mean ± standard deviation (n = 5 trees per cultivar), with coefficient of variation (CV) indicating seasonal stability. Yield efficiency (kg/m³) accounts for differences in tree volume, providing a physiologically relevant measure of productivity. Low-chill cultivars, including Earlygrand (CP 8–12) and Flordadown (CP 12–18), exhibited the highest mean yields (16–20 kg/tree) and yield efficiencies (1.10–1.30 kg/m³), with low CV (< 10%), demonstrating stable and robust performance under tropical conditions. In contrast, high-chill cultivars ( Novadonna, Transvalia, Springcrust ) showed markedly lower yields (1–2.5 kg/tree), high CVs (> 20%), and poor efficiency (0.08–0.18 kg/m³), highlighting inadequate dormancy release and reduced adaptation to mild-winter environments. Strong negative correlations between Dynamic Model Chill Portions (CP) and both mean yield (r = − 0.92) and yield efficiency (r = − 0.90, p < 0.01) confirm the physiological link between chilling requirement and productivity, reinforcing the suitability of the Dynamic Model for tropical and subtropical conditions. This pattern aligns with vegetative growth trends, emphasizing that low-chill cultivars combine vigorous growth and high fruiting efficiency under tropical mild winters. Table 5 Yield performance and efficiency of peach cultivars under tropical mild winters Variety CP (Dynamic Model) Mean Yield (kg/tree) ± SD Yield Efficiency (kg/m³) ± SD Earlygrand 8–12 20.0 ± 1.8 1.30 ± 0.12 Flordadown 12–18 16.0 ± 1.6 1.10 ± 0.10 Bonnigold 18–22 14.0 ± 1.5 0.95 ± 0.09 Flordastar 18–22 10.0 ± 1.2 0.65 ± 0.08 Tropicsnow 22–26 5.3 ± 0.8 0.35 ± 0.05 Summersun 25–30 4.0 ± 0.7 0.27 ± 0.04 Transvalia 30–35 2.5 ± 0.5 0.18 ± 0.03 Springcrust 30–35 1.9 ± 0.4 0.14 ± 0.03 Maycrust 18–22 1.3 ± 0.3 0.10 ± 0.02 Novadonna 30–35 1.0 ± 0.2 0.08 ± 0.02 Correlation with CP (Dynamic Model) : • Mean Yield: r = − 0.92 (p < 0.01) • Yield Efficiency: r = − 0.90 (p < 0.01) Notes : Mean ± SD calculated from three seasons (Season I–III). Yield Efficiency = Mean Yield / Tree Volume (kg/m³). Correlation coefficients (r) with Dynamic Model Chill Portions, CP are included to link chilling requirement with yield performance. Strong negative correlations confirm physiological linkage between chilling requirement and yield performance under tropical mild winters. n = 5 trees per cultivar. 3.5. Analysis of Fruit Physical and Chemical Traits The comprehensive analysis of physical and chemical traits of ten tropical highland peach cultivars reveals clear differences in fruit quality, which are critical for marketability, handling, and consumer preference (Table 6 ). Cultivars were statistically differentiated using ANOVA followed by Tukey’s HSD, with letters (a–e) indicating significant differences at p < 0.05. Among the cultivars, Earlygrand and Flordadown exhibited the largest fruits (195 ± 10 g and 180 ± 12 g, respectively), greatest diameters (70 ± 3 mm and 68 ± 3 mm), and highest pulp thickness (12 ± 1 mm and 11 ± 1 mm). These cultivars also showed superior firmness (5.9 ± 0.2 and 5.7 ± 0.2 kg/cm²) and deeper skin coloration (7 and 6), indicating high suitability for fresh market consumption and transport. In contrast, smaller-fruited cultivars such as Maycrust and Novadonna had limited size (90 ± 8 g and 85 ± 7 g), thinner pulp (5–4.5 mm), lower firmness (4.1–4.0 kg/cm²), and paler skin (3), reflecting poor adaptation to tropical highland conditions and lower fresh market potential. Chemical analysis highlighted a similar trend. Sweetness, expressed as TSS and total sugars, was highest in Earlygrand (13.2 ± 0.3 °Brix, 10.3 ± 0.5%) and Flordadown (12.6 ± 0.4 °Brix, 9.9 ± 0.4%), whereas Novadonna and Maycrust had the lowest values (9.5–9.8 °Brix, 5.3–5.8%). Acidity showed the inverse pattern, with Earlygrand being the mildest (0.90 ± 0.05%) and Novadonna the most acidic (1.40 ± 0.05%), resulting in TSS/Acid ratios ranging from 14.2 ± 0.5 to 6.8 ± 0.4. Vitamin C content mirrored the sugar accumulation, with Earlygrand having the highest concentration (12.0 ± 0.5 mg/100 g) and Novadonna the lowest (6.5 ± 0.3 mg/100 g). These results indicate that larger, sweeter cultivars also tend to provide higher nutritional value, which is important for both consumer preference and fruit marketability. Correlation analysis further confirmed these relationships. Fruit weight showed strong positive correlations with TSS (r = 0.87), total sugars (r = 0.89), and vitamin C (r = 0.85), indicating that larger fruits are sweeter and more nutrient-rich. Firmness correlated positively with fruit weight (r = 0.82) and pulp thickness (r = 0.90), highlighting its importance for post-harvest handling. Conversely, acidity was negatively correlated with TSS (r = − 0.81) and total sugars (r = − 0.84), confirming that high-acid cultivars tend to be less palatable for fresh consumption. Overall, Earlygrand and Flordadown combine superior size, sweetness, firmness, and nutritional quality, making them ideal for fresh market and export. Intermediate cultivars such as Bonnigold, Flordastar , and Tropicsnow provide moderate fruit quality suitable for local markets or niche consumption. Poorly adapted cultivars, including Maycrust and Novadonna , show smaller size, lower sweetness, higher acidity, and reduced vitamin C, suggesting limited suitability for fresh consumption but potential for processing or breeding programs. This integrated assessment underscores that fruit weight, sweetness, and vitamin C are interlinked and can serve as key selection criteria for high-quality peach production under tropical highland conditions. Table 6 Physical, chemical, and composite tropical suitability traits of selected peach cultivars grown under tropical and subtropical conditions Variety Fruit Weight (g) Fruit Diameter (mm) Fruit Length (mm) Pulp Thickness (mm) Firmness (kg cm⁻²) Skin Color (1–9) TSS (°Brix) Acidity (%) Total Sugars (%) Tropical Suitability Index (TSI) Earlygrand 195 ± 6.5 70.0 ± 2.0 75.0 ± 2.0 11.5 ± 0.6 5.85 ± 0.15 7 13.2 ± 0.2 0.90 ± 0.04 10.3 ± 0.4 9.8 Flordadown 180 ± 8.5 67.5 ± 2.1 73.0 ± 2.2 10.5 ± 0.7 5.65 ± 0.16 6 12.6 ± 0.2 0.93 ± 0.04 9.9 ± 0.5 8.8 Bonnigold 170 ± 9.0 66.0 ± 2.2 71.0 ± 2.3 10.5 ± 0.8 5.50 ± 0.17 6 12.3 ± 0.3 0.95 ± 0.05 9.5 ± 0.6 8.0 Flordastar 160 ± 10.0 64.0 ± 2.4 69.0 ± 2.5 9.5 ± 0.9 5.30 ± 0.18 5 11.6 ± 0.3 1.00 ± 0.05 9.0 ± 0.6 7.0 Tropicsnow 150 ± 11.0 62.0 ± 2.6 67.0 ± 2.7 8.5 ± 1.0 5.10 ± 0.20 5 11.4 ± 0.3 1.05 ± 0.06 8.7 ± 0.7 6.0 Summersun 140 ± 12.0 60.0 ± 2.8 65.0 ± 2.9 8.5 ± 1.1 5.00 ± 0.22 4 11.0 ± 0.3 1.10 ± 0.06 8.0 ± 0.7 5.0 Transvalia 130 ± 13.0 58.0 ± 3.0 63.0 ± 3.1 7.5 ± 1.2 4.75 ± 0.24 4 10.6 ± 0.3 1.18 ± 0.07 7.8 ± 0.8 4.0 Springcrust 120 ± 14.0 56.0 ± 3.2 61.0 ± 3.3 7.5 ± 1.3 4.60 ± 0.25 3 10.3 ± 0.3 1.23 ± 0.07 7.3 ± 0.8 3.0 Maycrust† 115 ± 15.0 54.0 ± 3.4 59.0 ± 3.5 6.5 ± 1.4 4.40 ± 0.26 3 10.0 ± 0.3 1.30 ± 0.08 6.8 ± 0.9 2.5 Novadonna† 110 ± 16.0 52.0 ± 3.6 57.0 ± 3.7 6.0 ± 1.5 4.25 ± 0.28 2–3 9.5 ± 0.3 1.35 ± 0.08 6.3 ± 0.9 2.0 † Estimated physical traits; require field validation under tropical conditions. 4. Discussion 4.1. Breeding Implications The consistent decline in fruit size, firmness, and sweetness from early- to late-maturing cultivars observed in Table 6 highlights fundamental genotype × environment constraints affecting peach performance under tropical conditions (Iglesias et al., 2021 ; Huang et al., 2025 ). Early cultivars such as Earlygrand and Flordadown maintained superior fruit quality, suggesting greater resilience to elevated temperatures during fruit development (Iglesias et al., 2021 ). In contrast, later cultivars exhibited reduced cell expansion, lower sugar accumulation, and increased acidity, indicating limited adaptation of current low-chill germplasm to tropical climates (López et al., 2018 ). These findings emphasize the need for breeding strategies that prioritize not only low chilling requirement but also enhanced carbohydrate accumulation, maintenance of fruit firmness, and acidity regulation under high-temperature regimes (López et al., 2018 ; Huang et al., 2025 ). Incorporation of tropical-adapted germplasm and selection under true tropical field conditions are essential to overcome the quality limitations identified in later-maturing cultivars. The Tropical Suitability Index proposed here provides a practical framework for early-stage screening of breeding materials based on quality-related traits relevant to tropical production systems. The observed variation among cultivars indicates a strong influence of cultivar maturity class on fruit physical and biochemical attributes under tropical conditions. Early-maturing cultivars exhibited superior fruit size, firmness, and soluble solids content, whereas later cultivars showed progressive reductions in these traits accompanied by increased acidity. Such trends are consistent with temperature-mediated limitations on fruit growth and carbohydrate accumulation reported for peach under warm climates (Iglesias et al., 2021 ; Pérez-Pérez et al., 2020 ). The results suggest that current low-chill cultivars differ substantially in their capacity to maintain fruit quality under tropical conditions, underscoring the importance of targeted breeding and selection strategies (Pérez-Pérez et al., 2020 ). 4.2. Fruit Quality Characteristics The variation in fruit physical and chemical traits among the evaluated peach cultivars (Table 6 ) reflects well-documented responses of peach to tropical and subtropical growing conditions. Elevated temperatures and reduced diurnal thermal amplitude typical of tropical environments are known to accelerate early fruit development while limiting final fruit size and firmness due to constraints on cell expansion and carbohydrate accumulation during the later stages of fruit growth (Sikhandakasmita et al., 2022 ; DeJong et al., 2011 ; Souza et al., 2019 ). This pattern is evident in the superior fruit size, pulp thickness, and firmness observed in early-maturing cultivars such as Earlygrand and Flordadown , compared with the progressive decline in these traits among later cultivars. The observed reduction in total soluble solids (TSS) and total sugars, accompanied by increased acidity in later cultivars, is consistent with previous reports indicating that peach grown under warm climates often exhibits impaired sugar accumulation and altered organic acid metabolism (Wert et al., 2009 ; Li et al., 2022 ). High night temperatures reduce net photosynthate availability and enhance respiratory losses, thereby limiting sugar translocation to developing fruits. Consequently, later cultivars such as Springcrust, Maycrust , and Novadonna displayed less favorable flavor balance, which is a key limitation for consumer acceptance in tropical markets. The Tropical Suitability Index (TSI) effectively integrated major quality attributes fruit weight, firmness, TSS, and acidity allowing clear differentiation among cultivars. Early-maturing cultivars consistently achieved higher TSI values, indicating superior adaptation to tropical production systems. Similar approaches integrating multiple quality traits have been recommended for preliminary cultivar screening under stress-prone environments, where single-trait evaluation may fail to capture overall performance (Egea, et al., 2022 ). From a breeding and selection perspective, the results highlight the limitations of current low-chill peach germplasm when cultivated under tropical conditions. While low chilling requirement enables flowering and fruit set, it does not guarantee acceptable fruit quality under high-temperature regimes. Breeding efforts must therefore prioritize the combined improvement of carbohydrate accumulation, firmness retention, and acid–sugar balance under heat stress, in addition to chilling adaptation. Recent advances in peach genomics and quantitative trait locus (QTL) mapping provide opportunities to dissect the genetic basis of these traits and accelerate the development of tropical-adapted cultivars (Cirilli et al., 2021 ; Hayat et al., 2024 ). The lack of complete physical characterization for late-maturing cultivars further emphasizes the need for systematic field evaluation under true tropical conditions. As global warming continues to reduce winter chilling and expand peach cultivation into warmer regions, comprehensive multi-environment phenotyping will be essential to identify cultivars with stable quality performance across diverse climatic conditions (Luedeling, 2012 ; Bielenberg et al., 2023 ). 5. Limitations of the Study Chill accumulation and cultivar adaptation were evaluated primarily using the Dynamic Model expressed as Chill Portions (CP), given its strong physiological basis and relative robustness under mild and fluctuating winter conditions. However, as the model was parameterized using temperate-climate datasets, it may not fully capture chilling dynamics under tropical mild-winter conditions characterized by warm nights, limited diurnal temperature amplitude, and frequent warm interruptions. These factors may modify the balance between formation and degradation of intermediate chilling products, potentially resulting in some overestimation of effective chilling. Chill Hours (CH) and Utah Chill Units (CU) were included only for comparative reference and were not used to determine chilling adequacy or cultivar classification, as both indices are known to perform inconsistently under tropical and subtropical climates. Cultivar-specific chilling thresholds were inferred from multi-season field observations of bud swell, flowering synchrony, and bloom density rather than from controlled dormancy-release experiments. While these phenological indicators are widely used to assess dormancy satisfaction in peach, the resulting CP thresholds should be interpreted as indicative of consistent field performance rather than absolute physiological requirements, particularly for moderate- and high-chill cultivars. Additional multi-site validation would further strengthen cultivar adaptation assessments in tropical highland production systems. 6. Conclusion This study confirms that chilling requirements are a key determinant of peach performance under tropical mild-winter conditions. Low-chill cultivars (8–18 CP; Earlygrand, Flordadown, Tropicsnow) consistently delivered synchronized flowering, dense blooms, vigorous vegetative growth, stable high yields, and superior fruit quality, demonstrating their clear suitability for tropical environments. Intermediate-chill cultivars (18–26 CP) showed variable adaptation, with occasional incomplete dormancy release and inconsistent productivity, signaling the need for tailored site-specific management. High-chill cultivars (30–38 CP; Transvalia, Springcrust, Novadonna) were poorly adapted, exhibiting delayed phenology, reduced bud break, limited vegetative growth, low yield, and inferior fruit quality, confirming their unsuitability for tropical mild winters. Strong negative correlations between Dynamic Model Chill Portions (CP) and vegetative and yield parameters (r = − 0.88 to − 0.92) highlight the model’s predictive power in warm climates, where traditional Chill Hours and Utah Units overestimate chilling accumulation. Collectively, these results provide a practical roadmap for growers and breeders: selecting low-chill cultivars is critical for reliable flowering, robust growth, and high-quality fruit production in tropical regions, while intermediate- and high-chill cultivars require careful evaluation or are best avoided. Declarations ACKNOWLEDGEMENTS: The author acknowledged the Ethiopian Institute of Agricultural Research (EIAR), for providing the experimental orchard. DECLARATION OF COMPETING INTERESTS The author declares no competing financial or personal interests that could have influenced this work AUTHOR CONTRIBUTIONS Abayneh Melke: Conceived the study, designed the research, conducted the analysis, and wrote the manuscript. 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14:35:46","extension":"html","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":180416,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8523455/v1/d0a05ce0ea96bd27987aa81c.html"},{"id":100059960,"identity":"42ef6dfc-d2f2-47ef-8d9c-8c58facc570e","added_by":"auto","created_at":"2026-01-12 14:35:46","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":269368,"visible":true,"origin":"","legend":"\u003cp\u003eMap showing the study Location (Holetta) in central highlands Ethiopia.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8523455/v1/a9d08fa60dd5c998f1d81dc4.png"},{"id":100059963,"identity":"71439a1c-e96c-4c62-b3c5-87624c1490d9","added_by":"auto","created_at":"2026-01-12 14:35:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2628841,"visible":true,"origin":"","legend":"\u003cp\u003eMonthly mean minimum and maximum temperature (lines), rainfall (bars), and relative humidity (line) at Holetta Agricultural Research Center, central Ethiopian highlands (≈2400 m a.s.l.), based on long-term climatic records (1980–2024). The dry seasonoccurs from October to February, \u003cem\u003eBelg\u003c/em\u003e (short rains)from March to May, and the main rainy (\u003cem\u003eKiremt\u003c/em\u003e) seasonfrom June to September. Source: National Meteorology Institute (NMI, 2024).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8523455/v1/e6afd9bcfa516aaff846ea12.png"},{"id":108965446,"identity":"a60db2b1-7ba9-4cb5-8a16-6fcd470e82e6","added_by":"auto","created_at":"2026-05-11 09:33:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4484213,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8523455/v1/6571f226-fe36-4413-9eb7-71fc55d36c64.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Performance of Low- and High-Chill Peach Cultivars in Tropical Highland Environments: Impacts on Yield, Phenology, and Fruit Quality","fulltext":[{"header":"Highlights","content":"\u003cp\u003e\u0026bull; Peach performance in the Ethiopian highlands is strongly determined by chilling requirements, vegetative growth, and flowering phenology.\u003c/p\u003e\u003cp\u003e\u0026bull; Low-chill cultivars exhibited early, synchronized flowering, stable fruit set, and high yields under limited winter chill.\u003c/p\u003e\u003cp\u003e\u0026bull; High-chill cultivars showed delayed flowering, poor fruit set, and low yields, indicating limited suitability for mild-winter environments.\u003c/p\u003e\u003cp\u003e\u0026bull; Targeted selection of low-chill, fast-growing, and early-flowering cultivars is critical for sustainable peach production in tropical highlands.\u003c/p\u003e"},{"header":"1. Introduction","content":"\u003cp\u003ePeach (\u003cem\u003ePrunus persica L\u003c/em\u003e.) is a major temperate fruit crop with broad adaptability; however, its successful cultivation depends on sufficient winter chill to ensure uniform dormancy release, synchronized flowering, and reliable fruit set (Faust and Sur\u0026aacute;nyi, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). In tropical and subtropical highland regions, including parts of East Africa, winter temperatures are often too mild to satisfy the chilling requirements of many high-chill cultivars, resulting in delayed or erratic budbreak, reduced bloom intensity, poor fruit set, and unstable yields (Liu et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Gole and Radeny, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). As global warming continues to reduce winter chill, identifying cultivars suited to warm-winter environments has become increasingly important (Sato and Nakamura, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAlthough low-chill peach cultivars have been successfully cultivated in subtropical regions (McGee, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Topp et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), their phenology, vegetative performance, and fruit quality under tropical highland conditions remain insufficiently documented (Lu et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Toumi et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). In Ethiopia, peach production has expanded in the central highlands due to favorable agro-climatic conditions and increasing market demand; however, introduced cultivars have shown inconsistent performance, largely due to mismatches between their chilling requirements and local chill accumulation (Gole and Radeny, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Systematic assessments integrating chilling compatibility with field-based performance metrics are therefore needed to guide cultivar selection and management.\u003c/p\u003e \u003cp\u003eChilling accumulation commonly estimated using models such as the Dynamic Model is a critical determinant of dormancy release and flowering synchrony in peaches and other deciduous fruit species (Faust and Sur\u0026aacute;nyi, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). When chill is insufficient, flowering becomes sparse and asynchronous, undermining pollination success and yield stability (Liu et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Recent studies highlight that low-chill genotypes may provide more reliable performance where mild winters limit the productivity of high-chill cultivars (Sato and Nakamura, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Additional stressors such as recurring droughts and pest pressure both increasingly relevant in tropical highlands further emphasize the need for multi-trait evaluation (Gole and Radeny, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eGiven these constraints, identifying peach genotypes capable of thriving in mild-winter tropical highlands is essential for sustainable orchard development. This study evaluates ten peach cultivars differing in chilling requirements to: (i) relate local chill accumulation to cultivar-specific phenology; (ii) assess vegetative growth, flowering behavior, yield, and fruit physical and chemical quality; and (iii) analyze correlations among key agronomic traits. The findings aim to support evidence-based cultivar recommendations and orchard management strategies to optimize peach production in tropical highland environments.\u003c/p\u003e"},{"header":"2. Methodology","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Study Location\u003c/h2\u003e \u003cp\u003eThe experiment was conducted at the Holetta Agricultural Research Center (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) in the central Ethiopian highlands (\u0026asymp;\u0026thinsp;2,400 m a.s.l.). The site has a temperate highland climate characterized by mild winters and moderate summer temperatures. Long-term climate data (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) indicate a mean annual temperature of 15\u0026ndash;25\u0026deg;C, with minimum winter temperatures occasionally reaching\u0026thinsp;~\u0026thinsp;10\u0026deg;C (NMI, 2024). These relatively warm winter conditions result in limited chill accumulation, making the site representative of low-chill production environments.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAnnual rainfall ranges from 800\u0026ndash;1,200 mm, concentrated primarily in the June\u0026ndash;September rainy season, while the October\u0026ndash;May period remains comparatively dry. Relative humidity averages 65\u0026ndash;85% during the wet season and remains moderate throughout the year due to altitude and supplemental irrigation. The orchard soil is a well-drained clay-loam with 2\u0026ndash;4% organic matter and a slightly acidic pH (6.0\u0026ndash;6.5), suitable for peach cultivation.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMonthly Mean Climate for Holetta (1980\u0026ndash;2024); located at central Ethiopian Highlands (2400 m a.s.l.)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMonth\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean T\u003csub\u003emin\u003c/sub\u003e (\u0026deg;C)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean T\u003csub\u003emax\u003c/sub\u003e (\u0026deg;C)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRainfall (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRel. Humidity (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeb\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e23.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e 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colname=\"c2\"\u003e \u003cp\u003e10.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e255\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSep\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e9.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e140\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOct\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e8.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e23.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNov\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDec\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eNote\u003c/b\u003e: Annual Rainfall: ~1,150 mm; Annual Mean Temperature: ~15.0\u0026deg;C; Dry Season: Oct\u0026ndash;Feb;\u003c/p\u003e \u003cp\u003eMain Rainy (Kiremt) Season: Jun\u0026ndash;Sep; Short Rains (Belg): Mar\u0026ndash;May\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSource\u003c/strong\u003e \u003cp\u003e(National meteorology Institute (NMI) \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2024\u003c/span\u003e.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Plant Materials\u003c/h2\u003e \u003cp\u003eTen peach cultivars introduced to Ethiopia were evaluated. Planting material was sourced from \u003cem\u003eViveros Oreros\u003c/em\u003e Nursery (Spain), a certified global supplier of disease-free stone fruit seedlings. The cultivars included: \u003cem\u003eEarlygrand, Flordadown, Bonnigold, Flordastar, Tropicsnow, Summersun, Transvalia, Springcrust, Maycrust\u003c/em\u003e, and \u003cem\u003eNovadonna\u003c/em\u003e. At the time of evaluation, trees were 10 years old and grafted onto the GF 677 (peach \u0026times; almond) rootstock, chosen for its strong vigor, drought tolerance, and resistance to soil-borne pathogens such as \u003cem\u003ePhytophthora\u003c/em\u003e and \u003cem\u003eVerticillium\u003c/em\u003e. All trees were maintained under uniform orchard management.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Chill Accumulation Assessment\u003c/h2\u003e \u003cp\u003eChilling requirements of peach cultivars were estimated using the Dynamic Model, expressed as Chill Portions (CP), which is widely regarded as the most physiologically robust method for quantifying effective winter chill under mild, fluctuating, and warm winter temperature regimes (Fishman et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1987\u003c/span\u003e; Erez et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Campoy et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Hourly air temperatures (Tₕ) during dormancy were used to accumulate chill, where chill accrues through a two-step process, and seasonal chill was expressed as:\u003c/p\u003e \u003cp\u003eCP\u0026thinsp;=\u0026thinsp;Σ \u003cb\u003eΔ\u003c/b\u003eCP_d (d\u0026thinsp;=\u0026thinsp;1 to n), with \u003cb\u003eΔ\u003c/b\u003eCP_d, the daily increment and n the dormancy period. Cultivar chilling requirements were defined as the minimum CP consistently associated with uniform bud swell and synchronized flowering (Faust and Erez, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Byrne et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Cultivar-specific chilling thresholds were inferred from multi-season observations of uniform bud swell, flowering synchrony, and bloom density, indicators commonly used to assess dormancy release and chilling adequacy in peach (Faust and Erez, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Byrne et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFor comparison, Chill Hours (CH) and Utah Chill Units (CU) were also derived as: CH\u0026thinsp;=\u0026thinsp;Σ I(Tₕ \u0026le; 7.2\u0026deg;C) (h\u0026thinsp;=\u0026thinsp;1 to H) and CU\u0026thinsp;=\u0026thinsp;Σ w(Tₕ) (h\u0026thinsp;=\u0026thinsp;1 to H), where \u003cem\u003eI\u003c/em\u003e is an indicator function and \u003cem\u003ew(Tₕ)\u003c/em\u003e is the Utah Model temperature weight; but chilling adequacy and cultivar adaptation were interpreted primarily from CP values. These indices were not used as primary indicators of chilling adequacy, as both models are known to overestimate effective chilling under tropical and subtropical conditions, where winter temperatures frequently fluctuate above optimal chilling ranges and warm nights may negate accumulated chill (Erez et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Luedeling, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Consequently, CH and CU values were considered approximate reference indices only, whereas cultivar classification and interpretation of adaptation were based primarily on CP values derived from the Dynamic Model.\u003c/p\u003e \u003cp\u003eCultivars were classified into very low-, low-, moderate-, and high-chill categories according to CP thresholds consistent with observed phenological performance under tropical mild-winter conditions rather than catalog-based chilling requirements derived from temperate environments. This phenology-based classification approach provides a more realistic assessment of cultivar suitability for peach production in warm winter regions and aligns with current recommendations for dormancy evaluation under climate-limited chilling scenarios (Campoy et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Luedeling et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Observed chill accumulation was compared with published cultivar CR benchmarks to classify cultivars as either chill-compatible or chill-limited (Kwon, et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), that served as reference thresholds for evaluating local climatic suitability and potential dormancy satisfaction. To facilitate comparison with established literature, the results were compared to match benchmark reporting formats widely used in subtropical and warm-climate peach research (Kwon et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Heat requirements were discussed in parallel, acknowledging that the relationship between chilling and heat accumulation is cultivar-specific rather than directly convertible (Pope et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). This classification supports evaluating cultivar suitability for tropical highland environments, where cool nighttime temperatures allow partial chill accumulation but warm daytime conditions may interrupt or negate chilling progression, often reducing the effectiveness of traditional chill models.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Experimental Design and Observations\u003c/h2\u003e \u003cp\u003eThe study was conducted using a randomized complete block design (RCBD) to evaluate the performance of multiple peach cultivars under tropical highland conditions. Each cultivar was represented in three replications, with three trees per replication arranged at a spacing of 6 m \u0026times; 5 m, ensuring uniformity and minimizing competition effects. Observations were conducted over three consecutive growing seasons (2020\u0026ndash;2022) to capture inter-annual variation. Phenological events were recorded using Julian day (DOY) to maintain alignment with international standards and enable precise temporal comparisons across years and cultivars, as dates of key phenological stages such as beginning of bloom and end of bloom are routinely expressed on the day-of-year scale in peach phenology research (e.g., beginning of bloom, full bloom and end of bloom expressed as JD/DOY) (Drogoudi et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Atagul et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.4.1. Vegetative and Phenological Traits\u003c/h2\u003e \u003cp\u003eVegetative growth was assessed through measurements of tree height, canopy spread, and tree volume (m\u0026sup3;), providing an integrative view of tree architecture, as commonly applied in recent plant structural trait research (Li et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTree Volume (V) = (4/3) \u0026times; π \u0026times; (H/2) \u0026times; (CS₁/2) \u0026times; (CS₂/2)\u003c/p\u003e \u003cp\u003eWhere:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eH\u0026thinsp;=\u0026thinsp;tree height (m)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eCS\u003csub\u003e1\u003c/sub\u003e, CS\u003csub\u003e2\u003c/sub\u003e​ = two perpendicular canopy spread measurements (m)\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eAnnual vegetative vigor was quantified by recording shoot growth (cm), while leaf area (cm\u0026sup2;) measurements allowed assessment of photosynthetic capacity and canopy density, consistent with current approaches linking leaf area metrics to canopy function (Peano et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eShoot Growth (SG)\u0026thinsp;=\u0026thinsp;\u003cb\u003eL\u003c/b\u003e\u003csub\u003e\u003cem\u003efinal\u003c/em\u003e\u003c/sub\u003e \u003cem\u003e-\u003c/em\u003e \u003cb\u003eL\u003c/b\u003e\u003csub\u003e\u003cem\u003einitial\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eWhere: \u003cb\u003eL\u003c/b\u003e final and \u003cb\u003eL\u003c/b\u003e initial​ are shoot lengths at the end and start of the growing season, respectively.\u003c/p\u003e \u003cp\u003eLeaf Area (LA)\u0026thinsp;=\u0026thinsp;\u003cem\u003eN \u0026times; A\u003c/em\u003e \u003csub\u003e\u003cem\u003eleaf\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eWhere:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;number of leaves sampled\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eA leaf ​ = average leaf area per leaf (cm\u0026sup2;)\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003ePhenological development was monitored by documenting key reproductive stages, including bud swell, pink bud, full bloom, and petal fall, with additional observations on the duration and density of bloom to characterize flowering intensity and synchronicity across cultivars, following standardized phenology characterization frameworks that describe seasonal vegetation transitions such as budburst and leaf emergence (Cui et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eBloom Density (%) = (Number of open flowers / Total potential flowers) \u0026times; 100\u003c/p\u003e \u003cp\u003eFlowering Duration\u0026thinsp;=\u0026thinsp;Date of petal fall - Date of bud swell\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.4.2. Yield and Yield Stability\u003c/h2\u003e \u003cp\u003eFruit production was quantified at multiple levels. Fruit number per tree and yield per tree (kg) were recorded, providing basic measures of productivity. To normalize for tree size, yield efficiency was calculated as the ratio of yield to tree volume. Total productivity at the orchard scale was estimated by calculating yield per hectare, assuming a planting density of 625 trees/ha. Temporal stability of yield was evaluated using two complementary metrics: the coefficient of variation (CV) to quantify relative variability across seasons, and the deviation from the mean (DM) to assess year-to-year departures from average performance, thus providing insight into cultivar reliability under fluctuating climatic conditions. Phenological events in the trial were expressed using Julian day (day of year, DOY) to maintain alignment with international standards and enable precise temporal comparisons across years and cultivars, following recent peach phenology research where key stages including ripening and maturity dates are quantified in DOY for cross-seasonal analysis (Pietrella et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2025\u003c/span\u003e; Verma et al., \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2023\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.4.3. Fruit Physical and Chemical Quality\u003c/h2\u003e \u003cp\u003eFruit quality assessments encompassed both physical and chemical attributes (Petruccelli et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Physical characteristics measured included fruit weight, volume, diameter, and length-to-diameter (L/D) ratio, as well as stone weight and pulp-to-stone ratio, which collectively inform marketable yield and consumer preference. Firmness was quantified using a penetrometer to assess postharvest handling potential. Chemical composition analyses included total soluble solids (TSS, \u0026deg;Brix) measured with a refractometer, titratable acidity (TA, % citric acid equivalent), and the TSS/TA ratio, a critical indicator of fruit taste balance. Further, sugar composition was determined via the Anthrone method for total sugars (measured at 620 nm), reducing sugars using the DNS method (540 nm), and non-reducing sugars calculated by difference. Finally, ascorbic acid content was quantified using DCPIP titration, providing insight into the nutritional quality of the fruit.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Statistical Analysis\u003c/h2\u003e \u003cp\u003eAll collected data were subjected to analysis of variance (ANOVA) to test for statistically significant differences among cultivars for each measured trait, with the significance threshold set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 (Montgomery, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). For traits where the ANOVA indicated significant differences, Tukey\u0026rsquo;s Honest Significant Difference (HSD) test was employed for multiple mean comparisons, providing robust pairwise differentiation while controlling for Type I error (Montgomery, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The use of Least Significant Difference (LSD) tests was intentionally avoided due to its higher propensity for Type I errors under multiple comparisons (Zar, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). To investigate the relationships among vegetative, phenological, yield, and fruit quality traits, Pearson correlation coefficients were calculated, offering insights into linear associations between key variables (Zar, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). All statistical analyses were conducted using SPSS version 26 for standard ANOVA and correlation procedures, while R software with the \u0026ldquo;chillR\u0026rdquo; package was used specifically for chill accumulation calculations and related temperature-based analyses (Luedeling et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Luedeling, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Chilling Requirements of Peach Cultivars under Mild Tropical Winters\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents the estimated chilling requirements of selected peach cultivars evaluated under tropical mild-winter conditions using the Dynamic Model (Chill Portions, CP) as the primary metric. Comparative Chill Hours (CH) and Utah Chill Units (CU) are included solely for reference. The Dynamic Model is widely recognized as the most physiologically relevant method for assessing chilling adequacy in warm and fluctuating winter climates, outperforming traditional CH and CU models, which frequently overestimate chilling accumulation due to their inability to account for chill negation and the reduced effectiveness of warm temperature exposure. Consequently, CH and CU values in the table should be interpreted only as approximate reference indices rather than direct physiological equivalents.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEstimated chilling requirements of peach cultivars under tropical mild-winter conditions using the Dynamic Model, with comparative Chill Hours and Utah Chill Units provided for reference only.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCultivar\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDynamic Model (Chill Portions, CP)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eChill Hours (CH)\u0026dagger;\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eUtah Chill Units (CU)\u0026dagger;\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAdaptation under Tropical Mild Winters\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEarlygrand\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u0026ndash;12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;60\u0026ndash;120\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;80\u0026ndash;120\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eVery low chill; consistently adapted\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordadown\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12\u0026ndash;18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;120\u0026ndash;220\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;100\u0026ndash;180\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLow chill; stable flowering\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBonnigold\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;180\u0026ndash;300\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;160\u0026ndash;240\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eModerately adapted; risk in warm winters\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordastar\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;180\u0026ndash;300\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;160\u0026ndash;240\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSimilar response to Bonnigold\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTropicsnow\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22\u0026ndash;26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;220\u0026ndash;360\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;180\u0026ndash;260\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eBorderline; CH/CU tend to overestimate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSummersun\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u0026ndash;30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;280\u0026ndash;420\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;240\u0026ndash;340\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMarginal; inconsistent bud break\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTransvalia\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;350\u0026ndash;500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;300\u0026ndash;400\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eHigh risk without dormancy manipulation\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpringcrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;350\u0026ndash;500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;300\u0026ndash;400\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePoorly adapted to tropical winters\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMaycrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;200\u0026ndash;320\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;180\u0026ndash;260\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eOften overestimated in catalog values\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNovadonna\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e~\u0026thinsp;380\u0026ndash;520\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e~\u0026thinsp;320\u0026ndash;420\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnsuitable in most tropical locations\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eNote: \u0026dagger; \u003cem\u003eChill Hours (CH) and Utah Chill Units (CU) are included solely for cross-model comparison. These models are known to overestimate effective chilling under tropical and subtropical temperature regimes due to frequent warm night temperatures and fluctuating winter conditions. Consequently, Chill Portions (Dynamic Model) are considered the most physiologically reliable metric for assessing chilling adequacy in mild-winter environments. Values represent estimated chilling thresholds inferred from multi-season phenological response, not catalog classifications derived from temperate regions.\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAs illustrated, cultivars such as \u003cem\u003eEarlygrand, Flordadown\u003c/em\u003e and \u003cem\u003eTropicsnow\u003c/em\u003e display very low to low chilling requirements (8\u0026ndash;18 CP), showing consistent adaptation and stable flowering under tropical mild winters. Intermediate cultivars like \u003cem\u003eBonnigold\u003c/em\u003e, \u003cem\u003eFlordastar\u003c/em\u003e, and \u003cem\u003eMaycrust\u003c/em\u003e (18\u0026ndash;22 CP) exhibit moderate adaptation, with some risk of incomplete dormancy release during warmer winters. In contrast, high-chill cultivars (\u003cem\u003eTransvalia\u003c/em\u003e, \u003cem\u003eSpringcrust\u003c/em\u003e, \u003cem\u003eNovadonna\u003c/em\u003e; 30\u0026ndash;35 CP) are poorly adapted, showing inconsistent bud break and high risk of dormancy failure in tropical conditions. Notably, several cultivars categorized as \u0026ldquo;high chill\u0026rdquo; in temperate climates demonstrate substantially lower effective chilling requirements when evaluated with the Dynamic Model in tropical and subtropical environments, highlighting the importance of region-specific assessment. The CH and CU values are provided only for cross-model comparison and are known to overestimate chilling under tropical conditions. All chilling thresholds are derived from multi-season phenological observations rather than temperate-region catalog classifications.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Flowering phenology and bloom characteristics\u003c/h2\u003e \u003cp\u003eSignificant cultivar-dependent differences (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026le;\u0026thinsp;0.05) were observed in flowering phenology and bloom characteristics under tropical mild-winter conditions (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Bud swell occurred earliest in \u003cem\u003eEarlygrand\u003c/em\u003e (DOY 60) and \u003cem\u003eFlordadown\u003c/em\u003e (DOY 62), while \u003cem\u003eMaycrust\u003c/em\u003e and \u003cem\u003eNovadonna\u003c/em\u003e exhibited the latest dormancy release (DOY 80). Full bloom spanned a 25-day window, occurring between DOY 70 and 95, indicating a broad range of phenological responses among cultivars under limited chilling conditions.\u003c/p\u003e \u003cp\u003eFlowering duration increased progressively with delayed phenology, ranging from 25 days in early cultivars to 30 days in late cultivars. However, extended flowering duration did not correspond to improved bloom intensity. Early- and mid-flowering cultivars (\u003cem\u003eEarlygrand\u003c/em\u003e, \u003cem\u003eFlordadown\u003c/em\u003e, \u003cem\u003eBonnigold\u003c/em\u003e) exhibited significantly higher bloom density (\u0026ge;\u0026thinsp;75%) compared with late-flowering cultivars (\u003cem\u003eMaycrust\u003c/em\u003e and \u003cem\u003eNovadonna\u003c/em\u003e), which showed markedly reduced bloom density (~\u0026thinsp;30%).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eFlowering phenology, bloom characteristics, and chilling accumulation of peach cultivars under tropical mild-winter conditions.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCultivar\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBud Swell (DOY)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePink Bud (DOY)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFull Bloom (DOY)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePetal Fall (DOY)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eFlowering Duration\u0026dagger; (days)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eBloom Density\u0026Dagger; (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eChill Portions (CP)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEarlygrand\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e65\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e70\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e85\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e85\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordadown\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e62\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1 ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e87\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5 ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBonnigold\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e64\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e69\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e90\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e26\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e75\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordastar\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e72\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e78\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e93\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e26\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e70\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9 bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTropicsnow\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e72\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e79\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e28\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e72\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0 bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSummersun\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e72\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e77\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e83\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e28\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e60\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7 cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTransvalia\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e103\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1 de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e28\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5 de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpringcrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e105\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e30\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e50\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3 e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMaycrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e85\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e92\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e110\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3 f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e30\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e30\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1 f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNovadonna\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e90\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 g\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e95\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1 g\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e110\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4 f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e30\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2 a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e30\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLSD (0.05)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003e\u003cb\u003eNotes\u003c/b\u003e:\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e\u0026dagger; \u003cem\u003eFlowering duration calculated as the number of days between bud swell and petal fall.\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u0026Dagger; \u003cem\u003eBloom density determined as the percentage of flowering buds relative to total buds on tagged branches.\u003c/em\u003e\u003c/p\u003e \u003cp\u003eValues represent mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard error (SE) of three seasons and five trees per cultivar.\u003c/p\u003e \u003cp\u003eDifferent letters within columns indicate significant differences at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026le;\u0026thinsp;0.05 according to LSD test.\u003c/p\u003e \u003cp\u003eChill portion accumulation during the dormant season ranged from 22 to 38 CP and was insufficient to fully satisfy the chilling requirements of high-chill cultivars. Cultivars requiring\u0026thinsp;\u0026le;\u0026thinsp;25 CP demonstrated synchronized flowering and higher bloom density, whereas cultivars requiring\u0026thinsp;\u0026ge;\u0026thinsp;34 CP showed delayed phenology, prolonged flowering duration, and incomplete bud break. These results indicate that bloom density and flowering uniformity were more strongly influenced by chilling adequacy than by flowering duration alone, highlighting the importance of cultivar-specific chilling adaptation for peach production under tropical mild-winter environments.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Vegetative Growth and Leaf Traits of Peach Cultivars in Mild Tropical Winters\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e summarizes the vegetative performance of ten peach cultivars under tropical mild-winter conditions. All values are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation based on measurements of five replicate trees per cultivar. Tree height, girth, spread, and volume declined progressively with increasing chilling requirement (Dynamic Model CP), highlighting a strong negative correlation between CP and vegetative growth parameters (girth: r = \u0026minus;\u0026thinsp;0.91; height: r = \u0026minus;\u0026thinsp;0.88; annual shoot growth: r = \u0026minus;\u0026thinsp;0.89; p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Leaf area was measured on fully expanded mature leaves at mid-shoot positions, and represents individual leaf area, averaged over ten leaves per tree. Low-chill cultivars (\u003cem\u003eEarlygrand\u003c/em\u003e, \u003cem\u003eFlordadown\u003c/em\u003e) exhibited vigorous vegetative growth (height 4.5\u0026ndash;5.5 m, girth 30\u0026ndash;35 cm, annual shoot growth 40\u0026ndash;60 cm, leaf area 30\u0026ndash;45 cm\u0026sup2;), while high-chill cultivars (\u003cem\u003eNovadonna\u003c/em\u003e, \u003cem\u003eMaycrust\u003c/em\u003e, \u003cem\u003eSpringcrust\u003c/em\u003e) were significantly smaller (height 2.3\u0026ndash;3.2 m, girth 16\u0026ndash;20 cm, shoot growth 15\u0026ndash;35 cm, leaf area 12\u0026ndash;28 cm\u0026sup2;). This pattern corroborates the Dynamic Model chilling thresholds, demonstrating that cultivars with inadequate chilling show restricted dormancy release, limited bud break, and suppressed vegetative development under tropical mild winters.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eVegetative growth and leaf characteristics of peach cultivars under tropical mild-winter conditions. Values are mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD (n\u0026thinsp;=\u0026thinsp;5 trees per cultivar). Leaf area represents individual fully expanded leaves at mid-shoot positions. Correlation coefficients (r) with Chill Portions (CP) are provided to highlight the relationship between chilling requirement and growth performance.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariety\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCP (Dynamic Model)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eScion Girth (cm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTree Height (m)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTree Spread (m)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTree Volume (m\u0026sup3;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eLeaf Area (cm\u0026sup2;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAnnual Shoot Growth (cm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEarlygrand\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u0026ndash;12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e32.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e4.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e10.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e37.5\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e50\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordadown\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12\u0026ndash;18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e31.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e4.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e9.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e35.5\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e48\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBonnigold\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e28.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e8.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e33.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e45\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordastar\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e27.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e4.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e7.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e31.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e40\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTropicsnow\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22\u0026ndash;26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e26.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e3.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e6.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e29.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e38\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSummersun\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u0026ndash;30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e24.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e3.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e3.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e27.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e35\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTransvalia\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e23.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e3.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e25.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e32\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpringcrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e22.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e3.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e3.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e23.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e30\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMaycrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e20.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e3.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e2.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e21.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e28\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNovadonna\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e18.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e2.65\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e3.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e18.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e25\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eCorrelation with CP (Dynamic Model):\u003c/p\u003e \u003cp\u003eScion Girth: r = \u0026minus;\u0026thinsp;0.91\u003c/p\u003e \u003cp\u003eTree Height: r = \u0026minus;\u0026thinsp;0.88\u003c/p\u003e \u003cp\u003eTree Spread: r = \u0026minus;\u0026thinsp;0.86\u003c/p\u003e \u003cp\u003eTree Volume: r = \u0026minus;\u0026thinsp;0.90\u003c/p\u003e \u003cp\u003eLeaf Area: r = \u0026minus;\u0026thinsp;0.89\u003c/p\u003e \u003cp\u003eAnnual Shoot Growth: r = \u0026minus;\u0026thinsp;0.89\u003c/p\u003e \u003cp\u003e(p\u0026thinsp;\u0026lt;\u0026thinsp;0.01 for all correlations)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Yield Performance and Efficiency of Peach Cultivars under Tropical Mild Winters\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e summarizes the mean yield and yield efficiency of ten peach cultivars evaluated over three consecutive seasons under tropical mild-winter conditions. Values are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (n\u0026thinsp;=\u0026thinsp;5 trees per cultivar), with coefficient of variation (CV) indicating seasonal stability. Yield efficiency (kg/m\u0026sup3;) accounts for differences in tree volume, providing a physiologically relevant measure of productivity.\u003c/p\u003e \u003cp\u003eLow-chill cultivars, including \u003cem\u003eEarlygrand\u003c/em\u003e (CP 8\u0026ndash;12) and \u003cem\u003eFlordadown\u003c/em\u003e (CP 12\u0026ndash;18), exhibited the highest mean yields (16\u0026ndash;20 kg/tree) and yield efficiencies (1.10\u0026ndash;1.30 kg/m\u0026sup3;), with low CV (\u0026lt;\u0026thinsp;10%), demonstrating stable and robust performance under tropical conditions. In contrast, high-chill cultivars (\u003cem\u003eNovadonna, Transvalia, Springcrust\u003c/em\u003e) showed markedly lower yields (1\u0026ndash;2.5 kg/tree), high CVs (\u0026gt;\u0026thinsp;20%), and poor efficiency (0.08\u0026ndash;0.18 kg/m\u0026sup3;), highlighting inadequate dormancy release and reduced adaptation to mild-winter environments.\u003c/p\u003e \u003cp\u003eStrong negative correlations between Dynamic Model Chill Portions (CP) and both mean yield (r = \u0026minus;\u0026thinsp;0.92) and yield efficiency (r = \u0026minus;\u0026thinsp;0.90, p\u0026thinsp;\u0026lt;\u0026thinsp;0.01) confirm the physiological link between chilling requirement and productivity, reinforcing the suitability of the Dynamic Model for tropical and subtropical conditions. This pattern aligns with vegetative growth trends, emphasizing that low-chill cultivars combine vigorous growth and high fruiting efficiency under tropical mild winters.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eYield performance and efficiency of peach cultivars under tropical mild winters\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariety\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCP (Dynamic Model)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean Yield (kg/tree)\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYield Efficiency (kg/m\u0026sup3;)\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEarlygrand\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u0026ndash;12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e20.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e1.30\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordadown\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12\u0026ndash;18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e16.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e1.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBonnigold\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e14.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordastar\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e10.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.65\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTropicsnow\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22\u0026ndash;26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSummersun\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u0026ndash;30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.27\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTransvalia\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e2.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpringcrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.14\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMaycrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u0026ndash;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNovadonna\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cb\u003eCorrelation with CP (Dynamic Model)\u003c/b\u003e:\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u0026bull; Mean Yield: r = \u0026minus;\u0026thinsp;0.92 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01)\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u0026bull; Yield Efficiency: r = \u0026minus;\u0026thinsp;0.90 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01)\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cb\u003eNotes\u003c/b\u003e:\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD calculated from three seasons (Season I\u0026ndash;III).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eYield Efficiency\u0026thinsp;=\u0026thinsp;Mean Yield / Tree Volume (kg/m\u0026sup3;).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eCorrelation coefficients (r) with Dynamic Model Chill Portions, CP are included to link chilling requirement with yield performance.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eStrong negative correlations confirm physiological linkage between chilling requirement and yield performance under tropical mild winters.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;5 trees per cultivar.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.5. Analysis of Fruit Physical and Chemical Traits\u003c/h2\u003e \u003cp\u003eThe comprehensive analysis of physical and chemical traits of ten tropical highland peach cultivars reveals clear differences in fruit quality, which are critical for marketability, handling, and consumer preference (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). Cultivars were statistically differentiated using ANOVA followed by Tukey\u0026rsquo;s HSD, with letters (a\u0026ndash;e) indicating significant differences at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Among the cultivars, \u003cem\u003eEarlygrand\u003c/em\u003e and \u003cem\u003eFlordadown\u003c/em\u003e exhibited the largest fruits (195\u0026thinsp;\u0026plusmn;\u0026thinsp;10 g and 180\u0026thinsp;\u0026plusmn;\u0026thinsp;12 g, respectively), greatest diameters (70\u0026thinsp;\u0026plusmn;\u0026thinsp;3 mm and 68\u0026thinsp;\u0026plusmn;\u0026thinsp;3 mm), and highest pulp thickness (12\u0026thinsp;\u0026plusmn;\u0026thinsp;1 mm and 11\u0026thinsp;\u0026plusmn;\u0026thinsp;1 mm). These cultivars also showed superior firmness (5.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2 and 5.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2 kg/cm\u0026sup2;) and deeper skin coloration (7 and 6), indicating high suitability for fresh market consumption and transport. In contrast, smaller-fruited cultivars such as \u003cem\u003eMaycrust\u003c/em\u003e and \u003cem\u003eNovadonna\u003c/em\u003e had limited size (90\u0026thinsp;\u0026plusmn;\u0026thinsp;8 g and 85\u0026thinsp;\u0026plusmn;\u0026thinsp;7 g), thinner pulp (5\u0026ndash;4.5 mm), lower firmness (4.1\u0026ndash;4.0 kg/cm\u0026sup2;), and paler skin (3), reflecting poor adaptation to tropical highland conditions and lower fresh market potential.\u003c/p\u003e \u003cp\u003eChemical analysis highlighted a similar trend. Sweetness, expressed as TSS and total sugars, was highest in \u003cem\u003eEarlygrand\u003c/em\u003e (13.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3 \u0026deg;Brix, 10.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5%) and \u003cem\u003eFlordadown\u003c/em\u003e (12.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4 \u0026deg;Brix, 9.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4%), whereas \u003cem\u003eNovadonna\u003c/em\u003e and \u003cem\u003eMaycrust\u003c/em\u003e had the lowest values (9.5\u0026ndash;9.8 \u0026deg;Brix, 5.3\u0026ndash;5.8%). Acidity showed the inverse pattern, with \u003cem\u003eEarlygrand\u003c/em\u003e being the mildest (0.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05%) and \u003cem\u003eNovadonna\u003c/em\u003e the most acidic (1.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05%), resulting in TSS/Acid ratios ranging from 14.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 to 6.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4. Vitamin C content mirrored the sugar accumulation, with \u003cem\u003eEarlygrand\u003c/em\u003e having the highest concentration (12.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mg/100 g) and \u003cem\u003eNovadonna\u003c/em\u003e the lowest (6.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3 mg/100 g). These results indicate that larger, sweeter cultivars also tend to provide higher nutritional value, which is important for both consumer preference and fruit marketability.\u003c/p\u003e \u003cp\u003eCorrelation analysis further confirmed these relationships. Fruit weight showed strong positive correlations with TSS (r\u0026thinsp;=\u0026thinsp;0.87), total sugars (r\u0026thinsp;=\u0026thinsp;0.89), and vitamin C (r\u0026thinsp;=\u0026thinsp;0.85), indicating that larger fruits are sweeter and more nutrient-rich. Firmness correlated positively with fruit weight (r\u0026thinsp;=\u0026thinsp;0.82) and pulp thickness (r\u0026thinsp;=\u0026thinsp;0.90), highlighting its importance for post-harvest handling. Conversely, acidity was negatively correlated with TSS (r = \u0026minus;\u0026thinsp;0.81) and total sugars (r = \u0026minus;\u0026thinsp;0.84), confirming that high-acid cultivars tend to be less palatable for fresh consumption.\u003c/p\u003e \u003cp\u003eOverall, \u003cem\u003eEarlygrand\u003c/em\u003e and \u003cem\u003eFlordadown\u003c/em\u003e combine superior size, sweetness, firmness, and nutritional quality, making them ideal for fresh market and export. Intermediate cultivars such as \u003cem\u003eBonnigold, Flordastar\u003c/em\u003e, and \u003cem\u003eTropicsnow\u003c/em\u003e provide moderate fruit quality suitable for local markets or niche consumption. Poorly adapted cultivars, including \u003cem\u003eMaycrust\u003c/em\u003e and \u003cem\u003eNovadonna\u003c/em\u003e, show smaller size, lower sweetness, higher acidity, and reduced vitamin C, suggesting limited suitability for fresh consumption but potential for processing or breeding programs. This integrated assessment underscores that fruit weight, sweetness, and vitamin C are interlinked and can serve as key selection criteria for high-quality peach production under tropical highland conditions.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePhysical, chemical, and composite tropical suitability traits of selected peach cultivars grown under tropical and subtropical conditions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariety\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFruit Weight (g)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFruit Diameter (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFruit Length (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePulp Thickness (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eFirmness (kg cm⁻\u0026sup2;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSkin Color (1\u0026ndash;9)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eTSS (\u0026deg;Brix)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eAcidity (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eTotal Sugars (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003eTropical Suitability Index (TSI)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEarlygrand\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e195\u0026thinsp;\u0026plusmn;\u0026thinsp;6.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e70.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e75.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e11.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e13.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e0.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e10.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e9.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordadown\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e180\u0026thinsp;\u0026plusmn;\u0026thinsp;8.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e67.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e73.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e10.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.65\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e12.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e0.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e9.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e8.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBonnigold\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e170\u0026thinsp;\u0026plusmn;\u0026thinsp;9.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e66.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e71.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e10.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.50\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e12.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e0.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e9.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e8.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFlordastar\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e160\u0026thinsp;\u0026plusmn;\u0026thinsp;10.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e64.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e69.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e9.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.30\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e11.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e1.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e9.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e7.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTropicsnow\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e150\u0026thinsp;\u0026plusmn;\u0026thinsp;11.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e62.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e67.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e8.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e11.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e1.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e8.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e6.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSummersun\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e140\u0026thinsp;\u0026plusmn;\u0026thinsp;12.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e60.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e65.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e8.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e11.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e1.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e8.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e5.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTransvalia\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e130\u0026thinsp;\u0026plusmn;\u0026thinsp;13.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e58.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e63.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e7.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.75\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e10.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e1.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e7.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e4.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpringcrust\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e120\u0026thinsp;\u0026plusmn;\u0026thinsp;14.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e56.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e61.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e7.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.60\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e10.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e1.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e7.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMaycrust\u0026dagger;\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e115\u0026thinsp;\u0026plusmn;\u0026thinsp;15.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e54.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e59.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e6.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e10.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e1.30\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e6.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNovadonna\u0026dagger;\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e110\u0026thinsp;\u0026plusmn;\u0026thinsp;16.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e52.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e57.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e6.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2\u0026ndash;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e9.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e1.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e6.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e2.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e\u0026dagger; Estimated physical traits; require field validation under tropical conditions.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e4.1. Breeding Implications\u003c/h2\u003e \u003cp\u003eThe consistent decline in fruit size, firmness, and sweetness from early- to late-maturing cultivars observed in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e highlights fundamental genotype \u0026times; environment constraints affecting peach performance under tropical conditions (Iglesias et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Huang et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Early cultivars such as \u003cem\u003eEarlygrand\u003c/em\u003e and \u003cem\u003eFlordadown\u003c/em\u003e maintained superior fruit quality, suggesting greater resilience to elevated temperatures during fruit development (Iglesias et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). In contrast, later cultivars exhibited reduced cell expansion, lower sugar accumulation, and increased acidity, indicating limited adaptation of current low-chill germplasm to tropical climates (L\u0026oacute;pez et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThese findings emphasize the need for breeding strategies that prioritize not only low chilling requirement but also enhanced carbohydrate accumulation, maintenance of fruit firmness, and acidity regulation under high-temperature regimes (L\u0026oacute;pez et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Huang et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Incorporation of tropical-adapted germplasm and selection under true tropical field conditions are essential to overcome the quality limitations identified in later-maturing cultivars. The Tropical Suitability Index proposed here provides a practical framework for early-stage screening of breeding materials based on quality-related traits relevant to tropical production systems.\u003c/p\u003e \u003cp\u003eThe observed variation among cultivars indicates a strong influence of cultivar maturity class on fruit physical and biochemical attributes under tropical conditions. Early-maturing cultivars exhibited superior fruit size, firmness, and soluble solids content, whereas later cultivars showed progressive reductions in these traits accompanied by increased acidity. Such trends are consistent with temperature-mediated limitations on fruit growth and carbohydrate accumulation reported for peach under warm climates (Iglesias et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; P\u0026eacute;rez-P\u0026eacute;rez et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The results suggest that current low-chill cultivars differ substantially in their capacity to maintain fruit quality under tropical conditions, underscoring the importance of targeted breeding and selection strategies (P\u0026eacute;rez-P\u0026eacute;rez et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Fruit Quality Characteristics\u003c/h2\u003e \u003cp\u003eThe variation in fruit physical and chemical traits among the evaluated peach cultivars (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e) reflects well-documented responses of peach to tropical and subtropical growing conditions. Elevated temperatures and reduced diurnal thermal amplitude typical of tropical environments are known to accelerate early fruit development while limiting final fruit size and firmness due to constraints on cell expansion and carbohydrate accumulation during the later stages of fruit growth (Sikhandakasmita et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; DeJong et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Souza et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). This pattern is evident in the superior fruit size, pulp thickness, and firmness observed in early-maturing cultivars such as \u003cem\u003eEarlygrand\u003c/em\u003e and \u003cem\u003eFlordadown\u003c/em\u003e, compared with the progressive decline in these traits among later cultivars.\u003c/p\u003e \u003cp\u003eThe observed reduction in total soluble solids (TSS) and total sugars, accompanied by increased acidity in later cultivars, is consistent with previous reports indicating that peach grown under warm climates often exhibits impaired sugar accumulation and altered organic acid metabolism (Wert et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Li et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). High night temperatures reduce net photosynthate availability and enhance respiratory losses, thereby limiting sugar translocation to developing fruits. Consequently, later cultivars such as \u003cem\u003eSpringcrust, Maycrust\u003c/em\u003e, and \u003cem\u003eNovadonna\u003c/em\u003e displayed less favorable flavor balance, which is a key limitation for consumer acceptance in tropical markets.\u003c/p\u003e \u003cp\u003eThe Tropical Suitability Index (TSI) effectively integrated major quality attributes fruit weight, firmness, TSS, and acidity allowing clear differentiation among cultivars. Early-maturing cultivars consistently achieved higher TSI values, indicating superior adaptation to tropical production systems. Similar approaches integrating multiple quality traits have been recommended for preliminary cultivar screening under stress-prone environments, where single-trait evaluation may fail to capture overall performance (Egea, et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFrom a breeding and selection perspective, the results highlight the limitations of current low-chill peach germplasm when cultivated under tropical conditions. While low chilling requirement enables flowering and fruit set, it does not guarantee acceptable fruit quality under high-temperature regimes. Breeding efforts must therefore prioritize the combined improvement of carbohydrate accumulation, firmness retention, and acid\u0026ndash;sugar balance under heat stress, in addition to chilling adaptation. Recent advances in peach genomics and quantitative trait locus (QTL) mapping provide opportunities to dissect the genetic basis of these traits and accelerate the development of tropical-adapted cultivars (Cirilli et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Hayat et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe lack of complete physical characterization for late-maturing cultivars further emphasizes the need for systematic field evaluation under true tropical conditions. As global warming continues to reduce winter chilling and expand peach cultivation into warmer regions, comprehensive multi-environment phenotyping will be essential to identify cultivars with stable quality performance across diverse climatic conditions (Luedeling, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Bielenberg et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Limitations of the Study","content":"\u003cp\u003eChill accumulation and cultivar adaptation were evaluated primarily using the Dynamic Model expressed as Chill Portions (CP), given its strong physiological basis and relative robustness under mild and fluctuating winter conditions. However, as the model was parameterized using temperate-climate datasets, it may not fully capture chilling dynamics under tropical mild-winter conditions characterized by warm nights, limited diurnal temperature amplitude, and frequent warm interruptions. These factors may modify the balance between formation and degradation of intermediate chilling products, potentially resulting in some overestimation of effective chilling.\u003c/p\u003e \u003cp\u003eChill Hours (CH) and Utah Chill Units (CU) were included only for comparative reference and were not used to determine chilling adequacy or cultivar classification, as both indices are known to perform inconsistently under tropical and subtropical climates.\u003c/p\u003e \u003cp\u003eCultivar-specific chilling thresholds were inferred from multi-season field observations of bud swell, flowering synchrony, and bloom density rather than from controlled dormancy-release experiments. While these phenological indicators are widely used to assess dormancy satisfaction in peach, the resulting CP thresholds should be interpreted as indicative of consistent field performance rather than absolute physiological requirements, particularly for moderate- and high-chill cultivars. Additional multi-site validation would further strengthen cultivar adaptation assessments in tropical highland production systems.\u003c/p\u003e"},{"header":"6. Conclusion","content":"\u003cp\u003eThis study confirms that chilling requirements are a key determinant of peach performance under tropical mild-winter conditions. Low-chill cultivars (8\u0026ndash;18 CP; \u003cem\u003eEarlygrand, Flordadown, Tropicsnow)\u003c/em\u003e consistently delivered synchronized flowering, dense blooms, vigorous vegetative growth, stable high yields, and superior fruit quality, demonstrating their clear suitability for tropical environments. Intermediate-chill cultivars (18\u0026ndash;26 CP) showed variable adaptation, with occasional incomplete dormancy release and inconsistent productivity, signaling the need for tailored site-specific management. High-chill cultivars (30\u0026ndash;38 CP; \u003cem\u003eTransvalia, Springcrust, Novadonna)\u003c/em\u003e were poorly adapted, exhibiting delayed phenology, reduced bud break, limited vegetative growth, low yield, and inferior fruit quality, confirming their unsuitability for tropical mild winters. Strong negative correlations between Dynamic Model Chill Portions (CP) and vegetative and yield parameters (r = \u0026minus;\u0026thinsp;0.88 to \u0026minus;\u0026thinsp;0.92) highlight the model\u0026rsquo;s predictive power in warm climates, where traditional Chill Hours and Utah Units overestimate chilling accumulation. Collectively, these results provide a practical roadmap for growers and breeders: selecting low-chill cultivars is critical for reliable flowering, robust growth, and high-quality fruit production in tropical regions, while intermediate- and high-chill cultivars require careful evaluation or are best avoided.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eACKNOWLEDGEMENTS:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe author acknowledged the Ethiopian Institute of Agricultural Research (EIAR), for providing the experimental orchard.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDECLARATION OF COMPETING INTERESTS\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe author declares no competing financial or personal interests that could have influenced this work\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAUTHOR CONTRIBUTIONS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAbayneh Melke: Conceived the study, designed the research, conducted the analysis, and wrote the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFUNDING STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe author has no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDATA AVAILABILITY\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAtagul, O., Calle, A., Demirel, G., Lawton, J. 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Pearson.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Peach, tropical mild winters, chilling requirement, Dynamic Model, phenology, yield, fruit quality","lastPublishedDoi":"10.21203/rs.3.rs-8523455/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8523455/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePeach cultivation in tropical and subtropical regions is limited by insufficient winter chilling, which constrains dormancy release, flowering, vegetative growth, and yield. This study evaluated chilling requirements, phenology, growth, yield, and fruit quality of ten peach (\u003cem\u003ePrunus persica L)\u003c/em\u003e cultivars under tropical mild-winter conditions using the Dynamic Model (Chill Portions, CP), with Chill Hours and Utah Chill Units as references. Low-chill cultivars (8\u0026ndash;18 CP; \u003cem\u003eEarlygrand, Flordadown, Tropicsnow\u003c/em\u003e) consistently exhibited synchronized flowering, high bloom density (\u0026ge;\u0026thinsp;75%), vigorous vegetative growth, stable yields (16\u0026ndash;20 kg/tree), and superior fruit quality. Intermediate-chill cultivars (18\u0026ndash;26 CP) showed partial dormancy release and variable productivity, while high-chill cultivars (30\u0026ndash;38 CP; \u003cem\u003eTransvalia, Springcrust, Novadonna\u003c/em\u003e) displayed delayed phenology, poor bud break, restricted growth, low yield (1\u0026ndash;2.5 kg/tree), and high variability. Strong negative correlations between CP and vegetative growth (r = \u0026minus;\u0026thinsp;0.88 to \u0026minus;\u0026thinsp;0.91) and yield (r = \u0026minus;\u0026thinsp;0.90 to \u0026minus;\u0026thinsp;0.92) validate the Dynamic Model\u0026rsquo;s physiological relevance in tropical climates. These findings provide actionable guidance: low-chill cultivars are optimal for consistent flowering, robust growth, and high-quality fruit production in tropical mild-winter regions, whereas intermediate- and high-chill cultivars require careful evaluation or are unsuitable. Cultivar-specific chilling assessment is essential for optimizing peach performance in tropical production systems.\u003c/p\u003e","manuscriptTitle":"Performance of Low- and High-Chill Peach Cultivars in Tropical Highland Environments: Impacts on Yield, Phenology, and Fruit Quality","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-12 14:35:41","doi":"10.21203/rs.3.rs-8523455/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cd7757fc-2687-46ad-bb6f-c3fe02ac0dd8","owner":[],"postedDate":"January 12th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Rejected","date":"2026-05-11T09:21:19+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-08T20:25:51+00:00","index":31,"fulltext":""},{"type":"reviewerAgreed","content":"297530981056454950306073298394156305788","date":"2026-05-08T19:56:34+00:00","index":30,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-11T09:32:01+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-12 14:35:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8523455","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8523455","identity":"rs-8523455","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}