Enhancing growth and graft success of shea (Vitellaria paradoxa C.F. Gaertn) through targeted inoculation with indigenous arbuscular mycorrhizal fungi

Enhancing growth and graft success of shea (Vitellaria paradoxa C.F. Gaertn) through targeted inoculation with indigenous arbuscular mycorrhizal fungi | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Enhancing growth and graft success of shea (Vitellaria paradoxa C.F. Gaertn) through targeted inoculation with indigenous arbuscular mycorrhizal fungi Abdel Aziz Ben Yaya ZOUNGRANA, Hadou HARO, Madina Alima Tapsoba, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9199452/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 12 You are reading this latest preprint version Abstract Vitellaria paradoxa is a keystone species of West African agroforestry systems, yet its regeneration is constrained by slow juvenile growth and low grafting success. Arbuscular mycorrhizal fungi (AMF) have the potential to enhance seedling vigor, but their contribution to the production of graftable rootstocks remains poorly documented. This study evaluated the effects of six indigenous AMF inocula on mycorrhizal colonization, early growth, and graft success of V. paradoxa under nursery conditions. Seedlings were inoculated with six indigenous AMF inocula or left uninoculated as controls. Mycorrhizal colonization was assessed at 9 and 16 months after inoculation, while growth parameters were measured up to 9 months. The plants were then grafted using the terminal cleft grafting technique, and graft success was evaluated 90 days after grafting. The relationship between grafting success rate and plant growth was analysed using binary logistic regression, including collar diameter as a covariate. Mycorrhizal colonization differed markedly among inocula, with M3 and M2 showing the highest colonization frequency and intensity at 16 months. Inoculation significantly enhanced seedling growth, particularly collar diameter, with M1 and M3 producing the most vigorous rootstocks. Graft success was strongly improved by AMF inoculation, reaching 96% with M3 compared to 32% in uninoculated controls. Logistic modeling revealed a positive association between collar diameter and graft success. These results demonstrate that targeted inoculation with indigenous AMF inocula can substantially improve the production of graftable shea rootstocks and enhance graft success. Integrating AMF inoculation for vigorous seedlings offers a promising strategy to accelerate shea parkland restoration. Biological sciences/Ecology Earth and environmental sciences/Ecology Biological sciences/Microbiology Biological sciences/Plant sciences Arbuscular mycorrhizal fungi Vitellaria paradoxa indigenous inocula Burkina Faso Figures Figure 1 Figure 2 1. Introduction The shea tree ( Vitellaria paradoxa C.F. Gaertn.) is a keystone component of West African agroforestry parklands, yet its long-term persistence is threatened by weak recruitment and constraints on regeneration in cultivated landscapes (Aleza et al. 2015 ; Ræbild et al. 2012 ). In Burkina Faso and across the Sudanian zone, regeneration dynamics are shaped by land-use intensity and seasonal seedling mortality, which ultimately limits the renewal of adult tree populations (Ræbild et al. 2012 ). To accelerate domestication and dissemination of elite genotypes, vegetative propagation by grafting is widely promoted, but graft success in shea can be variable under nursery conditions (Yao et al. 2020 ). In woody species, graft establishment is widely understood to depend on both technical control (method, timing, aftercare) and the physiological status of the rootstock, for which simple morphological traits (e.g., collar diameter) are commonly used as operational proxies (Yao et al. 2020 ). However, in shea, the extent to which rootstock vigor quantitatively predicts graft success under routine nursery conditions remains insufficiently documented. Arbuscular mycorrhizal fungi (AMF) are known to improve plant nutrition and growth, particularly in low-fertility soils where phosphorus availability limits early development (Begum et al. 2019 ; Etesami et al. 2021 ). Recent syntheses suggest that AMF inoculation generally increases plant biomass and enhances nitrogen and phosphorus acquisition, while also emphasizing strong context dependence linked to inoculum identity and experimental conditions (Chandrasekaran 2020 ; Wu et al. 2024 ). This dependence on context is especially relevant for agroforestry species and nursery systems, where local inocula may differ in their ability to colonize hosts and translate symbiosis into practical growth gains. In shea propagation, AMF inoculation is therefore expected to influence grafting outcomes mainly indirectly , by improving rootstock vigor rather than acting directly on graft union formation. Given that graft success is a binary outcome and biological variability is expected, logistic regression provides an appropriate framework to evaluate whether continuous vigor traits (e.g., collar diameter) are positively associated with success probability without implying a deterministic relationship (Hoffmann and Poorter 2002 ). The present study evaluated six indigenous AMF inocula for their effects on mycorrhizal colonization, early growth, and graft success of V. paradoxa under nursery conditions. Specifically, we tested whether AMF inoculation improves rootstock vigor and whether collar diameter at grafting shows a positive association with graft success. 2. Materials and Methods 2.1. Plant material and planting The plant material consisted of shea nuts harvested from mature trees in Burkina Faso. In accordance with national regulations, public research institutions have authorized access to plant genetic resources for scientific research purposes. No protected or endangered species were involved in this study. The plant material was identified as Vitellaria paradoxa C.F. Gaertn. based on taxonomic references from the Herbier National du Burkina Faso (HNBU, Institut de l’Environnement et de Recherches Agricoles). A voucher specimen is available at HNBU under accession number HNBU00398, collected in Saponé, Burkina Faso, and taxonomically verified by HNBU in 2010. The specimen is publicly accessible through the JSTOR Global Plants database. After germination, seedlings were grown individually in 5‑litre plastic pots filled with unsterilized sandy soil. According to analyses from the Bureau National des Sols, the soil contained 90.2% sand, 3.9% clay and 5.9% silt, with 0.33% organic matter, 0.02% total nitrogen, 1.7 ppm available phosphorus, and a pH (H₂O) of 6.4. The soil was air-dried, sieved (2 mm) and homogenized before use. All plants were managed using identical watering practices under nursery conditions. 2.2. AMF inoculation and assessment of root colonization Six indigenous arbuscular mycorrhizal fungal (AMF) inocula (M1–M6) were obtained from the ‘Laboratoire de Microbiologie Forestière’ of INERA (Burkina Faso). All inocula consisted of mixed AMF communities isolated from the rhizosphere of the following host plant species: Vigna unguiculata (M1 containing Scutellospora spp , Gigaspora spp, and Glomus spp (Haro et al. , 2012)), Sclerocarya birrea (M2), Vitellaria paradoxa (M3 - M5), and Senegalia macrostachya (M6). One month after seedling emergence, plants were inoculated with 10 g of AMF inoculum placed directly in contact with the root system. Each inoculum consisted of a mixture of soil, spores, hyphae and colonized root fragments. Inoculum density was not standardized in terms of spore number. Root samples were collected from each individual plant at 9 and 16 months after inoculation. Roots were cleared and stained following the method of Phillips and Hayman ( 1970 ). Mycorrhizal frequency and intensity were quantified according to the method of Trouvelot et al. ( 1986 ). 2.3. Treatments and experimental design A completely randomized design was used in the nursery to evaluate the effects of AMF inoculation on seedling growth and mycorrhizal colonization. Seven treatments were tested (six AMF inocula and one uninoculated control) with 20 individual plants per treatment. Each pot containing one plant represented an experimental unit. The uninoculated control plants (T0) received no inoculum. However, because the experiment was conducted in non-sterilized soil, control plants harbored a background AMF community. Treatment effects should therefore be interpreted as the outcome of targeted enrichment with indigenous AMF consortia rather than a strict comparison between mycorrhizal and non-mycorrhizal plants. 2.4. Growth measurement Plant height and collar diameter were measured at the time of inoculation and nine months after inoculation. Height was measured from the soil surface to the apical bud, and collar diameter was measured at the root–shoot junction using a digital caliper. Relative growth rates in height (RGRh) and collar diameter (RGRdc) were calculated following Hoffmann and Poorter ( 2002 ): $$\:RGR=\frac{\text{l}\text{n}\left({X}_{2}\right)-\text{l}\text{n}\left({X}_{1}\right)}{{T}_{2}-{T}_{1}}$$ where \(\:{X}_{1}\) and \(\:{X}_{2}\) represent the initial and final values of the measured parameter, and \(\:{T}_{1}\) and \(\:{T}_{2}\) the corresponding times. 2.5. Grafting procedure and assessment After evaluating growth, the plants were then used to assess grafting success. The plants were arranged in a completely randomised block design comprising four blocks, each containing four plants for each treatment, i.e. 16 grafted plants per treatment. Terminal cleft grafting was performed during the rainy season (August). Scions were collected from a single selected donor tree to minimize genetic variability. Scions of similar diameter were used. Rootstock collar diameter at grafting ranged from 4.8 to 10.0 mm. All grafts were performed by the same operator using identical techniques, including scion preparation, ligation, application of grafting wax, shading and humidity management. Graft success was assessed based on scion survival 90 days after grafting. Bud burst at 30 days was recorded as an intermediate indicator. 2.9. Statistical analyses Growth and mycorrhizal colonization data were analyzed using XLSTAT 2020. Normality of residuals and homogeneity of variances were assessed using the Shapiro–Wilk and Levene tests, respectively. When parametric assumptions were met, one‑way analysis of variance (ANOVA) was performed, followed by Newman-Keuls test for multiple comparisons at α = 0.05. When assumptions were not met, the non‑parametric Kruskal–Wallis test was applied, followed by the Conover–Iman post‑hoc test. Graft success (survival at 90 days) was analyzed using binary logistic regression in SPSS version 27. Graft success (0 = failure, 1 = success) was used as the dependent variable, collar diameter at grafting as a continuous covariate, and block as a fixed factor. Odds ratios (Exp(B)) and their 95% confidence intervals were calculated. Model fit was assessed using the Hosmer–Lemeshow goodness-of-fit test. Statistical significance was evaluated at α = 0.05. 3. Results 3.1. Mycorrhizal root colonization Mycorrhizal colonization of Vitellaria paradoxa roots differed significantly among inoculation treatments at both 9 and 16 months after inoculation (Table 1 ). Table 1 Mycorrhizal frequency and intensity of Vitellaria paradoxa roots at 9 and 16 months after inoculation with indigenous AMF inocula. Treatment 9 months after inoculation 16 months after inoculation Mycorrhizal frequency (%) Mycorrhizal intensity (%) Mycorrhizal frequency (%) Mycorrhizal intensity (%) M1 28 ± 6 a 4 ± 2 ab 72 ± 7 a 35 ± 7 ab M2 41 ± 7 cd 7 ± 2 bc 86 ± 6 cd 51 ± 7 bc M3 53 ± 6 bc 7 ± 3 c 95 ± 3 bc 76 ± 3 c M4 62 ± 8 e 17 ± 5 ab 76 ± 5 e 32 ± 5 ab M5 83 ± 4 cd 20 ± 3 a 53 ± 7 cd 16 ± 5 a M6 87 ± 5 de 36 ± 7 ab 65 ± 10 de 36 ± 11 ab T0 55 ± 6 ab 14 ± 4 b 76 ± 6 ab 35 ± 6 b p-value 0.002 < 0.0001 < 0.0001 < 0.0001 In the same column, values sharing the same letter are not significantly different at the 5% significance level according to the Newman-Keuls test (column 1) and the Conover-Iman test (columns 2–4). At 9 months, mycorrhizal frequency ranged from 28% in M1 to 87% in M6. Inocula M6 and M5 exhibited the highest colonization frequencies, which were significantly greater than those observed in M1, M2 and M3 (p < 0.01). Mycorrhizal intensity at this stage remained relatively low overall, varying from 4% in M1 to 36% in M6, with M5 also showing comparatively high intensity values. At 16 months, colonization frequency increased markedly in most treatments. Inoculum M3 reached the highest frequency (95%), followed by M2 (86%) and M1 (72%). Mycorrhizal intensity also increased substantially over time, with M3 exhibiting the highest intensity (76%), significantly exceeding all other treatments (p < 0.001). M2 showed intermediate intensity (51%), whereas M1, M4, M6 and the uninoculated control displayed moderate values ranging from 32% to 36%. In contrast, M5 showed a decline in colonization intensity at 16 months. Overall, there were consistent differences in symbiotic establishment and persistence among indigenous AMF inocula, with M3 and M2 showing the most sustained colonization over time. 3.2. Seedling growth 9 months after inoculation Initial plant height and collar diameter measured at the time of inoculation did not differ significantly among treatments (p > 0.05), indicating homogeneous starting conditions (Table 2 ). Nine months after inoculation, significant differences in plant height were observed among treatments (p = 0.001). Seedlings inoculated with M1 attained the greatest mean height (16.6 cm), followed by M3 (15.7 cm), both significantly taller than seedlings inoculated with M4 and the uninoculated control. Intermediate heights were recorded for M2, M5 and M6. Table 2 Height, collar diameter and relative growth rates of Vitellaria paradoxa seedlings at inoculation and 9 months after inoculation. Treatments At the time of inoculation Nine months after inoculation Height 1 (cm) Diameter 1 (mm) Height 2 (cm) Diameter 2 (mm) RGRh (month − 1 ) (X1000) RGRdc (month − 1 ) (X1000) M1 7.3 ± 0.6 a 3.4 ± 0.2 a 16.6 ± 0.9 a 5.9 ± 0.3 a 92 ± 5 a 62 ± 4 a M2 6.0 ± 0.5 a 2.6 ± 0.2 a 13.2 ± 1.0 abc 4.7 ± 0.3 bc 88 ± 5 a 70 ± 10 a M3 6.8 ± 0.5 a 3.0 ± 0.2 a 15.7 ± 1.0 ab 5.5 ± 0.3 ab 90 ± 10 a 72 ± 5 a M4 5.3 ± 0.4 a 2.6 ± 0.2 a 11.5 ± 0.9 c 4.4 ± 0.3 bc 80 ± 10 a 57 ± 4 a M5 6.1 ± 0.5 a 2.6 ± 0.3 a 13.7 ± 0.9 abc 4.9 ± 0.4 abc 90 ± 10 a 80 ± 10 a M6 5.0 ± 0.4 a 2.3 ± 0.2 a 12.9 ± 0.6 bc 4.3 ± 0.3 c 110 ± 10 a 70 ± 10 a T0 5.9 ± 0.6 a 2.6 ± 0.2 a 12.1 ± 1.0 c 4.6 ± 0.3 c 80 ± 10 a 65 ± 5 a p-value NS NS 0.001 0.002 NS NS For the same column (height, collar diameter, relative height growth rate, or relative collar diameter growth rate), values sharing at least one identical letter are not significantly different according to the Conover–Iman test at the 5% significance level. RGRh: relative growth rate in height. RGRcd: relative growth rate in collar diameter. Collar diameter at 9 months also differed significantly among treatments (p = 0.002). The largest diameters were observed in seedlings inoculated with M1 (5.9 mm) and M3 (5.5 mm), whereas M4 and M6 exhibited the smallest values. Uninoculated control plants showed intermediate collar diameters. Relative growth rates in height (RGRh) and collar diameter (RGRdc) did not differ significantly among treatments (p > 0.05), indicating that treatment effects were primarily expressed through cumulative growth rather than differences in relative growth dynamics. 3.3. Graft success rate Graft success at 90 days after grafting differed significantly among inoculation treatments (Fig. 1 ). Inoculation with AMF inoculum M3 resulted in the highest graft success rate (96%), representing a three-fold increase compared to the uninoculated control (32%). Intermediate success rates were observed for M1, M2, M4 and M5, ranging from 58% to 87%, corresponding to increases of 81–172% relative to the control. Inoculum M6 showed a moderate improvement compared to the control but remained lower than the best-performing treatments. These results demonstrate that AMF inoculation substantially enhanced graft success, with pronounced differences among inocula. 3.4. Relationship between collar diameter and graft success Binary logistic regression analysis was performed to assess the effect of collar diameter at grafting on graft success at 90 days, while controlling for block effects (Table 3 , Fig. 2 ). The model showed an adequate fit to the data, as indicated by the Hosmer–Lemeshow goodness-of-fit test (χ² = 11.11, df = 8, p = 0.196), suggesting no significant deviation between observed and predicted values. Table 3 Binary logistic regression analysis of graft success as a function of collar diameter Variable B SE Odds ratio (Exp(B)) 95% CI p-value Collar diameter (mm) 0.324 0.191 1.38 0.95–2.01 0.091 Collar diameter showed a positive association with graft success (B = 0.324, SE = 0.191), corresponding to an odds ratio of 1.38 (95% CI: 0.95–2.01; p = 0.091). 4. Discussion 4.1. Differential establishment of indigenous AMF inocula The observed differences in mycorrhizal frequency and intensity among inoculation treatments suggest that indigenous AMF inocula vary substantially in their capacity to establish and persist in Vitellaria paradoxa root systems. Such variability is consistent with previous work showing that AMF effectiveness depends strongly on host–fungus compatibility and environmental context (Begum et al. 2019 ; Haro et al. 2017 ). In particular, inoculum M3 exhibited high colonization frequency and intensity at 16 months, suggesting sustained symbiotic establishment rather than transient infection. Sustained colonization is especially relevant for woody perennials, where functional benefits of mycorrhization often accumulate over time and contribute to long-term improvements in nutrient acquisition and plant vigor (Smith and Read 2008 ; Wu et al. 2024 ). Although colonization intensity alone does not guarantee functional benefits, the strong establishment observed for M3 provides a plausible biological basis for its superior performance in subsequent growth and grafting stages. 4.2. Effects of AMF inoculation on early seedling growth AMF inoculation enhanced early seedling growth under a low-fertility sandy substrate, particularly by increasing collar diameter. This response is consistent with the well-documented role of AMF in improving phosphorus uptake and overall nutrient status under nutrient-limited conditions (Smith and Read 2008 ; Wu et al. 2024 ). Recent meta-analyses have shown that AMF inoculation generally increases plant biomass and nutrient acquisition, although effect sizes vary depending on inoculum identity and experimental conditions (Wu et al. 2024 ). The absence of significant differences in relative growth rates suggests that inoculation effects were expressed primarily through cumulative growth rather than changes in instantaneous growth dynamics. From a nursery perspective, increased collar diameter is particularly relevant, as it reflects improved structural development and potential physiological capacity of the rootstock. 4.3. AMF inoculation and graft success A major outcome of this study is the substantial increase in graft success observed in AMF-inoculated plants, with inoculum M3 achieving markedly higher success rates than uninoculated controls. This finding supports the hypothesis that improving rootstock vigor through biological inoculation can enhance graft establishment in shea, a species known for variable grafting success under nursery conditions (Yao et al. 2020 ). Logistic regression analysis revealed a positive association between collar diameter at grafting and graft success probability. Each 1 mm increase in collar diameter increased the odds of graft success by approximately 38%, although this effect was marginally significant (p = 0.091) and the 95% confidence interval slightly overlapped unity. The relationship between collar diameter and graft success should be interpreted as probabilistic rather than deterministic. Collar diameter represents an operational proxy of rootstock vigor, integrating multiple underlying physiological attributes, but does not constitute a direct mechanistic driver of graft union formation. The marginal statistical significance observed in the logistic model suggests that additional, unmeasured factors such as carbohydrate reserves, cambial activity, hormonal balance, or post-grafting microenvironmental conditions likely interact with rootstock size to determine grafting outcomes. This result indicates a biologically meaningful trend, while also highlighting that collar diameter alone does not fully explain grafting outcomes. Such a pattern is consistent with grafting physiology, where rootstock vigor, cambial activity and carbohydrate availability contribute to callus formation and vascular reconnection, but interact with additional technical and environmental factors (Hartmann et al. 2011 ). The absence of a significant block effect further suggests that grafting conditions were homogeneous and that the observed trend reflects intrinsic plant characteristics rather than experimental artefacts. 4.4. Collar diameter as a practical, but not exclusive, predictor of graft success The positive trend linking collar diameter to graft success supports the use of this trait as a practical indicator of rootstock quality in nursery operations. Larger collar diameter likely reflects better-developed vascular tissues and greater physiological capacity to support graft union formation (Hartmann et al. 2011 ). However, the marginal statistical significance observed here indicates that collar diameter should be viewed as a contributory factor, rather than a sole determinant of graft success. This nuanced interpretation is important for operational recommendations: selecting vigorous rootstocks based on collar diameter can improve grafting efficiency, but optimal outcomes will also depend on grafting technique, scion quality and post-grafting management (Yao et al. 2020 ). 4.5. Implications for shea propagation and restoration strategies Taken together, the results suggest that targeted inoculation with high-performing indigenous AMF inocula can improve both rootstock vigor and grafting outcomes in Vitellaria paradoxa . While the relationship between collar diameter and graft success is not strictly deterministic, the observed positive trend supports integrating AMF inoculation with morphological selection criteria to enhance nursery efficiency. Given the slow juvenile growth of shea and the need to accelerate parkland restoration, such combined strategies could reduce propagation time and losses, provided that benefits persist after field transplantation. Field-level validation across contrasting edaphoclimatic conditions remains a critical next step (Boffa 2015 ). 4.6. Limitations and perspectives Two main limitations should be acknowledged. First, the inocula consisted of mixed AMF communities without standardized spore density or taxonomic characterization, limiting mechanistic attribution to specific fungal taxa. Because the study was conducted in non-sterilized soil, the uninoculated control plants were colonized by a background AMF community. Consequently, the observed effects reflect functional differences among indigenous AMF consortia rather than a binary comparison between mycorrhizal and non-mycorrhizal conditions. Second, although collar diameter showed a positive association with graft success, the non-statistical significance indicates that additional physiological or environmental variables likely contribute to grafting outcomes. Future research should combine inoculum characterization, physiological measurements of rootstock status and multi-site field trials to refine predictive models of graft success and optimize AMF-based propagation strategies for shea. It should be noted that physiological mechanisms potentially underlying graft success, such as carbohydrate reserves, cambial activity or hormonal status of the rootstock, were not directly measured in this study. 5. Conclusions This study demonstrates that targeted inoculation of Vitellaria paradoxa seedlings with selected indigenous arbuscular mycorrhizal fungi (AMF) can substantially improve nursery performance and grafting outcomes. Among the inocula tested, M3 consistently showed superior performance, combining sustained mycorrhizal colonization, enhanced seedling growth, and the highest graft success rate under nursery conditions. AMF inoculation significantly increased collar diameter, a key morphological trait associated with rootstock vigor. Binary logistic regression analysis revealed a positive association between collar diameter at grafting and graft success probability, indicating that more vigorous rootstocks tend to exhibit higher graft establishment rates. However, the marginal statistical significance of this relationship suggests that collar diameter should be considered an important contributory factor rather than a sole or deterministic predictor of graft success. The strong improvement in graft success observed in AMF-inoculated plants highlights the practical value of integrating biological inoculation strategies with morphological selection criteria in shea nurseries. Such an approach can enhance propagation efficiency, reduce losses during grafting, and shorten the production cycle of graft-ready seedlings. Overall, these findings support the use of high-performing indigenous AMF inocula as a low-input, ecologically sound strategy to improve shea propagation and contribute to the restoration and rehabilitation of degraded parkland agroforestry systems. Future research should focus on multi-site field validation, long-term performance of inoculated grafted plants, and optimization of inoculation protocols for large-scale nursery application. Declarations Conflict of interest The authors declare that they have no conflict of interest. Author Contribution Zoungrana Abdel Aziz Ben Yaya conducted the nursery experiment, performed data collection, and contributed to data analysis. Haro Hadou conceived and supervised the study, contributed to experimental design, statistical analyses, and led the writing and revision of the manuscript. Tapsoba Madina Alima participated in experimental implementation, data collection, and preliminary analyses.Dianda Mahamadi contributed to the experimental design, provided technical support for mycorrhizal analyses, and critically reviewed the manuscript.All authors read and approved the final manuscript. Acknowledgement This study was made possible through funding provided by the Government of Burkina Faso via the “Fonds National de la Recherche et de l'Innovation pour le Devéloppement (FONRID)”. Data Availability The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. References Aleza K, Wala K, Bayala J, Villamor GB, Dourma M, Atakpama W, Akpagana K (2015) Population structure and regeneration status of Vitellaria Paradoxa (C. F. Gaertner) under different land management regimes in Atacora department, Benin Agroforestry Systems 89:511-523 doi:10.1007/s10457-015-9787-9 Begum N et al. (2019) Role of Arbuscular Mycorrhizal Fungi in Plant Growth Regulation: Implications in Abiotic Stress Tolerance Frontiers in Plant Science Volume 10 - 2019 doi:10.3389/fpls.2019.01068 Boffa J-M (2015) Opportunities and challenges in the improvement of the shea ( Vitellaria paradoxa ) resource and its management vol 24. World Agroforestry Centre (ICRAF), Nairobi Chandrasekaran M (2020) A Meta-Analytical Approach on Arbuscular Mycorrhizal Fungi Inoculation Efficiency on Plant Growth and Nutrient Uptake Agriculture 10:370 Etesami H, Jeong BR, Glick BR (2021) Contribution of Arbuscular Mycorrhizal Fungi, Phosphate–Solubilizing Bacteria, and Silicon to P Uptake by Plant Frontiers in Plant Science Volume 12 - 2021 doi:10.3389/fpls.2021.699618 Haro H, Sanon KB, Le Roux C, Duponnois R, Traoré AS (2017) Improvement of cowpea productivity by rhizobial and mycorrhizal inoculation in Burkina Faso Symbiosis 74:107-120 doi:10.1007/s13199-017-0478-3 Hartmann HT, Kester DE, Davies FT, Geneve RL (2011) Plant Propagation: Principles and Practices. Prentice Hall, Hoffmann WA, Poorter H (2002) Avoiding bias in calculations of relative growth rate Annals of botany 90:37-42 doi:10.1093/aob/mcf140 Phillips JM, Hayman DS (1970) Improved procedures for clearing roots and staining parasitic and vesicular-arbuscular mycorrhizal fungi for rapid assessment of infection Transactions of the British Mycological Society 55:158-161 Ræbild A, Hansen UB, Kambou S (2012) Regeneration of Vitellaria paradoxa and Parkia biglobosa in a parkland in Southern Burkina Faso Agroforestry Systems 85:443-453 doi:10.1007/s10457-011-9397-0 Smith SE, Read DJ (2008) Mycorrhizal symbiosis. vol ISBN 978-0-12-652840-4. Third edition. Academic press, London Trouvelot A, Kough JL, Gianinazzi-Pearson V, Gianinazzi S (1986) Mesure du taux de mycorhization VA d’un système radiculaire. Recherche de méthodes d’estimation ayant une signification fonctionnelle Mycorrhizae : physiology and genetics:217-221 Wu Y, Chen C, Wang G (2024) Inoculation with arbuscular mycorrhizal fungi improves plant biomass and nitrogen and phosphorus nutrients: a meta-analysis BMC plant biology 24:960 doi:10.1186/s12870-024-05638-9 Yao SDM, Diarrassouba N, Alui KA, et al. (2020) Effect of the grafting method on the recovery and growth of juvenile shea plants grafted in nursery East African Scholars Journal of Agriculture and Life Sciences 3:406-414 doi:10.36349/easjals.2020.v03i12.005 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9199452","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":619714283,"identity":"91212882-a93c-494d-a65a-18ca1aafc388","order_by":0,"name":"Abdel Aziz Ben Yaya ZOUNGRANA","email":"","orcid":"","institution":"Institut de l'Environnement et de Recherches Agricoles (INERA)","correspondingAuthor":false,"prefix":"","firstName":"Abdel","middleName":"Aziz Ben Yaya","lastName":"ZOUNGRANA","suffix":""},{"id":619714286,"identity":"1c3e1c23-e181-4f04-95c2-2804d1c0b70b","order_by":1,"name":"Hadou HARO","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyklEQVRIiWNgGAWjYBACAyBmBiP2BhAJponVwnMAogVIE6tFIoFILebsZx8+LqixljO4+cbwc0GFDQOPNAE9lj3pxsYzjqUbG9zOMZaecSaNgYcvgYDDDqSxSfOwHU7ccDvHQJq37TCDPQ8hv5x/BtTyD6jl5hnj3yAtPAS13ADaAlSZuOEGj5k0kVqeMRvz9qUbS55JK7PmOZPGQ1jL+TTGxzzfrOX4jh/efJunwkaOoBYkwAGKIwYSNABTygNSVI+CUTAKRsEIAgB20jtRXuYdkQAAAABJRU5ErkJggg==","orcid":"","institution":"Institut de l'Environnement et de Recherches Agricoles (INERA)","correspondingAuthor":true,"prefix":"","firstName":"Hadou","middleName":"","lastName":"HARO","suffix":""},{"id":619714287,"identity":"d14781b8-580d-40ad-840a-5ff0bdd23928","order_by":2,"name":"Madina Alima Tapsoba","email":"","orcid":"","institution":"Institut de l'Environnement et de Recherches Agricoles (INERA)","correspondingAuthor":false,"prefix":"","firstName":"Madina","middleName":"Alima","lastName":"Tapsoba","suffix":""},{"id":619714290,"identity":"3b2966c9-c1ae-4ba1-ab25-e7bc13cfad99","order_by":3,"name":"Mahamadi Dianda","email":"","orcid":"","institution":"Institut de l'Environnement et de Recherches Agricoles (INERA)","correspondingAuthor":false,"prefix":"","firstName":"Mahamadi","middleName":"","lastName":"Dianda","suffix":""}],"badges":[],"createdAt":"2026-03-23 10:53:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9199452/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9199452/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106616058,"identity":"b2519527-9a43-4488-9402-eb6c970c495a","added_by":"auto","created_at":"2026-04-10 13:12:26","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":35644,"visible":true,"origin":"","legend":"\u003cp\u003eGraft success rate (%) of \u003cem\u003eVitellaria paradoxa\u003c/em\u003e seedlings inoculated with indigenous AMF inocula and uninoculated control at 90 days after grafting\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9199452/v1/60374d2108cf1d1ffa04dc52.png"},{"id":106616206,"identity":"f4989610-5823-4799-bb59-1b8b3737eeb6","added_by":"auto","created_at":"2026-04-10 13:12:57","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":53714,"visible":true,"origin":"","legend":"\u003cp\u003ePredicted probability of graft success as a function of collar diameter at grafting based on a binary logistic regression model. Points represent individual grafted plants (\u003cem\u003en\u003c/em\u003e = 112)\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9199452/v1/00d57d2bfd7111365081d80c.png"},{"id":106616220,"identity":"7cc1cfca-d63f-4a9a-b5d6-21f91e066a34","added_by":"auto","created_at":"2026-04-10 13:13:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1040600,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9199452/v1/34c66b9a-f8de-4585-9927-ea7df66644ef.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Enhancing growth and graft success of shea (Vitellaria paradoxa C.F. Gaertn) through targeted inoculation with indigenous arbuscular mycorrhizal fungi","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe shea tree (\u003cem\u003eVitellaria paradoxa\u003c/em\u003e C.F. Gaertn.) is a keystone component of West African agroforestry parklands, yet its long-term persistence is threatened by weak recruitment and constraints on regeneration in cultivated landscapes (Aleza et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; R\u0026aelig;bild et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). In Burkina Faso and across the Sudanian zone, regeneration dynamics are shaped by land-use intensity and seasonal seedling mortality, which ultimately limits the renewal of adult tree populations (R\u0026aelig;bild et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo accelerate domestication and dissemination of elite genotypes, vegetative propagation by grafting is widely promoted, but graft success in shea can be variable under nursery conditions (Yao et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In woody species, graft establishment is widely understood to depend on both technical control (method, timing, aftercare) and the physiological status of the rootstock, for which simple morphological traits (e.g., collar diameter) are commonly used as operational proxies (Yao et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). However, in shea, the extent to which rootstock vigor quantitatively predicts graft success under routine nursery conditions remains insufficiently documented.\u003c/p\u003e \u003cp\u003eArbuscular mycorrhizal fungi (AMF) are known to improve plant nutrition and growth, particularly in low-fertility soils where phosphorus availability limits early development (Begum et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Etesami et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Recent syntheses suggest that AMF inoculation generally increases plant biomass and enhances nitrogen and phosphorus acquisition, while also emphasizing strong context dependence linked to inoculum identity and experimental conditions (Chandrasekaran \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Wu et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). This dependence on context is especially relevant for agroforestry species and nursery systems, where local inocula may differ in their ability to colonize hosts and translate symbiosis into practical growth gains.\u003c/p\u003e \u003cp\u003eIn shea propagation, AMF inoculation is therefore expected to influence grafting outcomes mainly \u003cb\u003eindirectly\u003c/b\u003e, by improving rootstock vigor rather than acting directly on graft union formation. Given that graft success is a binary outcome and biological variability is expected, logistic regression provides an appropriate framework to evaluate whether continuous vigor traits (e.g., collar diameter) are positively associated with success probability without implying a deterministic relationship (Hoffmann and Poorter \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2002\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe present study evaluated six indigenous AMF inocula for their effects on mycorrhizal colonization, early growth, and graft success of \u003cem\u003eV. paradoxa\u003c/em\u003e under nursery conditions. Specifically, we tested whether AMF inoculation improves rootstock vigor and whether collar diameter at grafting shows a positive association with graft success.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Plant material and planting\u003c/h2\u003e \u003cp\u003eThe plant material consisted of shea nuts harvested from mature trees in Burkina Faso. In accordance with national regulations, public research institutions have authorized access to plant genetic resources for scientific research purposes. No protected or endangered species were involved in this study. The plant material was identified as \u003cem\u003eVitellaria paradoxa\u003c/em\u003e C.F. Gaertn. based on taxonomic references from the Herbier National du Burkina Faso (HNBU, Institut de l\u0026rsquo;Environnement et de Recherches Agricoles). A voucher specimen is available at HNBU under accession number HNBU00398, collected in Sapon\u0026eacute;, Burkina Faso, and taxonomically verified by HNBU in 2010. The specimen is publicly accessible through the JSTOR Global Plants database.\u003c/p\u003e \u003cp\u003eAfter germination, seedlings were grown individually in 5‑litre plastic pots filled with unsterilized sandy soil. According to analyses from the Bureau National des Sols, the soil contained 90.2% sand, 3.9% clay and 5.9% silt, with 0.33% organic matter, 0.02% total nitrogen, 1.7 ppm available phosphorus, and a pH (H₂O) of 6.4. The soil was air-dried, sieved (2 mm) and homogenized before use. All plants were managed using identical watering practices under nursery conditions.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. AMF inoculation and assessment of root colonization\u003c/h2\u003e \u003cp\u003eSix indigenous arbuscular mycorrhizal fungal (AMF) inocula (M1\u0026ndash;M6) were obtained from the \u0026lsquo;Laboratoire de Microbiologie Foresti\u0026egrave;re\u0026rsquo; of INERA (Burkina Faso). All inocula consisted of mixed AMF communities isolated from the rhizosphere of the following host plant species: \u003cem\u003eVigna unguiculata\u003c/em\u003e (M1 containing \u003cem\u003eScutellospora spp\u003c/em\u003e, \u003cem\u003eGigaspora\u003c/em\u003e spp, and \u003cem\u003eGlomus\u003c/em\u003e spp (Haro \u003cem\u003eet al.\u003c/em\u003e, 2012)), \u003cem\u003eSclerocarya birrea\u003c/em\u003e (M2), \u003cem\u003eVitellaria paradoxa\u003c/em\u003e (M3 - M5), and \u003cem\u003eSenegalia macrostachya\u003c/em\u003e (M6).\u003c/p\u003e \u003cp\u003eOne month after seedling emergence, plants were inoculated with 10 g of AMF inoculum placed directly in contact with the root system. Each inoculum consisted of a mixture of soil, spores, hyphae and colonized root fragments. Inoculum density was not standardized in terms of spore number. Root samples were collected from each individual plant at 9 and 16 months after inoculation. Roots were cleared and stained following the method of Phillips and Hayman (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1970\u003c/span\u003e). Mycorrhizal frequency and intensity were quantified according to the method of Trouvelot et al. (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1986\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Treatments and experimental design\u003c/h2\u003e \u003cp\u003eA completely randomized design was used in the nursery to evaluate the effects of AMF inoculation on seedling growth and mycorrhizal colonization. Seven treatments were tested (six AMF inocula and one uninoculated control) with 20 individual plants per treatment. Each pot containing one plant represented an experimental unit. The uninoculated control plants (T0) received no inoculum. However, because the experiment was conducted in non-sterilized soil, control plants harbored a background AMF community. Treatment effects should therefore be interpreted as the outcome of targeted enrichment with indigenous AMF consortia rather than a strict comparison between mycorrhizal and non-mycorrhizal plants.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Growth measurement\u003c/h2\u003e \u003cp\u003ePlant height and collar diameter were measured at the time of inoculation and nine months after inoculation. Height was measured from the soil surface to the apical bud, and collar diameter was measured at the root\u0026ndash;shoot junction using a digital caliper.\u003c/p\u003e \u003cp\u003eRelative growth rates in height (RGRh) and collar diameter (RGRdc) were calculated following Hoffmann and Poorter (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2002\u003c/span\u003e):\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:RGR=\\frac{\\text{l}\\text{n}\\left({X}_{2}\\right)-\\text{l}\\text{n}\\left({X}_{1}\\right)}{{T}_{2}-{T}_{1}}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ewhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{X}_{1}\\)\u003c/span\u003e\u003c/span\u003eand \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{X}_{2}\\)\u003c/span\u003e\u003c/span\u003erepresent the initial and final values of the measured parameter, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{T}_{1}\\)\u003c/span\u003e\u003c/span\u003eand \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{T}_{2}\\)\u003c/span\u003e\u003c/span\u003ethe corresponding times.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Grafting procedure and assessment\u003c/h2\u003e \u003cp\u003eAfter evaluating growth, the plants were then used to assess grafting success. The plants were arranged in a completely randomised block design comprising four blocks, each containing four plants for each treatment, i.e. 16 grafted plants per treatment.\u003c/p\u003e \u003cp\u003eTerminal cleft grafting was performed during the rainy season (August). Scions were collected from a single selected donor tree to minimize genetic variability. Scions of similar diameter were used. Rootstock collar diameter at grafting ranged from 4.8 to 10.0 mm. All grafts were performed by the same operator using identical techniques, including scion preparation, ligation, application of grafting wax, shading and humidity management. Graft success was assessed based on scion survival 90 days after grafting. Bud burst at 30 days was recorded as an intermediate indicator.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.9. Statistical analyses\u003c/h2\u003e \u003cp\u003eGrowth and mycorrhizal colonization data were analyzed using XLSTAT 2020. Normality of residuals and homogeneity of variances were assessed using the Shapiro\u0026ndash;Wilk and Levene tests, respectively. When parametric assumptions were met, one‑way analysis of variance (ANOVA) was performed, followed by Newman-Keuls test for multiple comparisons at α\u0026thinsp;=\u0026thinsp;0.05. When assumptions were not met, the non‑parametric Kruskal\u0026ndash;Wallis test was applied, followed by the Conover\u0026ndash;Iman post‑hoc test.\u003c/p\u003e \u003cp\u003eGraft success (survival at 90 days) was analyzed using binary logistic regression in SPSS version 27. Graft success (0\u0026thinsp;=\u0026thinsp;failure, 1\u0026thinsp;=\u0026thinsp;success) was used as the dependent variable, collar diameter at grafting as a continuous covariate, and block as a fixed factor. Odds ratios (Exp(B)) and their 95% confidence intervals were calculated. Model fit was assessed using the Hosmer\u0026ndash;Lemeshow goodness-of-fit test. Statistical significance was evaluated at α\u0026thinsp;=\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Mycorrhizal root colonization\u003c/h2\u003e \u003cp\u003eMycorrhizal colonization of \u003cem\u003eVitellaria paradoxa\u003c/em\u003e roots differed significantly among inoculation treatments at both 9 and 16 months after inoculation (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\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\u003eMycorrhizal frequency and intensity of \u003cem\u003eVitellaria paradoxa\u003c/em\u003e roots at 9 and 16 months after inoculation with indigenous AMF inocula.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTreatment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e9 months after inoculation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e16 months after inoculation\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMycorrhizal frequency (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMycorrhizal intensity (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMycorrhizal frequency (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMycorrhizal intensity (%)\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\u003eM1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e72\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e35\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e86\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e51\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e76\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e62\u0026thinsp;\u0026plusmn;\u0026thinsp;8\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e76\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e32\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e83\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e53\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e16\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM6\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e87\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e36\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e65\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e36\u0026thinsp;\u0026plusmn;\u0026thinsp;11\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eT0\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e76\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e35\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e\u003cem\u003eIn the same column, values sharing the same letter are not significantly different at the 5% significance level according to the Newman-Keuls test (column 1) and the Conover-Iman test (columns 2\u0026ndash;4).\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAt 9 months, mycorrhizal frequency ranged from 28% in M1 to 87% in M6. Inocula M6 and M5 exhibited the highest colonization frequencies, which were significantly greater than those observed in M1, M2 and M3 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Mycorrhizal intensity at this stage remained relatively low overall, varying from 4% in M1 to 36% in M6, with M5 also showing comparatively high intensity values.\u003c/p\u003e \u003cp\u003eAt 16 months, colonization frequency increased markedly in most treatments. Inoculum M3 reached the highest frequency (95%), followed by M2 (86%) and M1 (72%). Mycorrhizal intensity also increased substantially over time, with M3 exhibiting the highest intensity (76%), significantly exceeding all other treatments (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). M2 showed intermediate intensity (51%), whereas M1, M4, M6 and the uninoculated control displayed moderate values ranging from 32% to 36%. In contrast, M5 showed a decline in colonization intensity at 16 months.\u003c/p\u003e \u003cp\u003eOverall, there were consistent differences in symbiotic establishment and persistence among indigenous AMF inocula, with M3 and M2 showing the most sustained colonization over time.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Seedling growth 9 months after inoculation\u003c/h2\u003e \u003cp\u003eInitial plant height and collar diameter measured at the time of inoculation did not differ significantly among treatments (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05), indicating homogeneous starting conditions (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Nine months after inoculation, significant differences in plant height were observed among treatments (p\u0026thinsp;=\u0026thinsp;0.001). Seedlings inoculated with M1 attained the greatest mean height (16.6 cm), followed by M3 (15.7 cm), both significantly taller than seedlings inoculated with M4 and the uninoculated control. Intermediate heights were recorded for M2, M5 and M6.\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\u003eHeight, collar diameter and relative growth rates of \u003cem\u003eVitellaria paradoxa\u003c/em\u003e seedlings at inoculation and 9 months after inoculation.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTreatments\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eAt the time of inoculation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eNine months after inoculation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHeight 1\u003c/p\u003e \u003cp\u003e(cm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDiameter 1\u003c/p\u003e \u003cp\u003e(mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHeight 2\u003c/p\u003e \u003cp\u003e(cm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eDiameter 2\u003c/p\u003e \u003cp\u003e(mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRGRh (month\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) (X1000)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eRGRdc (month\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) (X1000)\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\u003eM1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e92\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e62\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003csup\u003eabc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e88\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e70\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e90\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e72\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e57\u0026thinsp;\u0026plusmn;\u0026thinsp;4\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003csup\u003eabc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003csup\u003eabc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e90\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eM6\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e110\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e70\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eT0\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e80\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e65\u0026thinsp;\u0026plusmn;\u0026thinsp;5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ep-value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003e\u003cem\u003eFor the same column (height, collar diameter, relative height growth rate, or relative collar diameter growth rate), values sharing at least one identical letter are not significantly different according to the Conover\u0026ndash;Iman test at the 5% significance level.\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eRGRh: relative growth rate in height. RGRcd: relative growth rate in collar diameter.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eCollar diameter at 9 months also differed significantly among treatments (p\u0026thinsp;=\u0026thinsp;0.002). The largest diameters were observed in seedlings inoculated with M1 (5.9 mm) and M3 (5.5 mm), whereas M4 and M6 exhibited the smallest values. Uninoculated control plants showed intermediate collar diameters.\u003c/p\u003e \u003cp\u003eRelative growth rates in height (RGRh) and collar diameter (RGRdc) did not differ significantly among treatments (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05), indicating that treatment effects were primarily expressed through cumulative growth rather than differences in relative growth dynamics.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Graft success rate\u003c/h2\u003e \u003cp\u003eGraft success at 90 days after grafting differed significantly among inoculation treatments (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Inoculation with AMF inoculum M3 resulted in the highest graft success rate (96%), representing a three-fold increase compared to the uninoculated control (32%).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIntermediate success rates were observed for M1, M2, M4 and M5, ranging from 58% to 87%, corresponding to increases of 81\u0026ndash;172% relative to the control. Inoculum M6 showed a moderate improvement compared to the control but remained lower than the best-performing treatments.\u003c/p\u003e \u003cp\u003eThese results demonstrate that AMF inoculation substantially enhanced graft success, with pronounced differences among inocula.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Relationship between collar diameter and graft success\u003c/h2\u003e \u003cp\u003eBinary logistic regression analysis was performed to assess the effect of collar diameter at grafting on graft success at 90 days, while controlling for block effects (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The model showed an adequate fit to the data, as indicated by the Hosmer\u0026ndash;Lemeshow goodness-of-fit test (χ\u0026sup2; = 11.11, df\u0026thinsp;=\u0026thinsp;8, p\u0026thinsp;=\u0026thinsp;0.196), suggesting no significant deviation between observed and predicted values.\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\u003eBinary logistic regression analysis of graft success as a function of collar diameter\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOdds ratio (Exp(B))\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCollar diameter (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.324\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.191\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.95\u0026ndash;2.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.091\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 \u003c/p\u003e \u003cp\u003eCollar diameter showed a positive association with graft success (B\u0026thinsp;=\u0026thinsp;0.324, SE\u0026thinsp;=\u0026thinsp;0.191), corresponding to an odds ratio of 1.38 (95% CI: 0.95\u0026ndash;2.01; p\u0026thinsp;=\u0026thinsp;0.091).\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e4.1. Differential establishment of indigenous AMF inocula\u003c/h2\u003e \u003cp\u003eThe observed differences in mycorrhizal frequency and intensity among inoculation treatments suggest that indigenous AMF inocula vary substantially in their capacity to establish and persist in \u003cem\u003eVitellaria paradoxa\u003c/em\u003e root systems. Such variability is consistent with previous work showing that AMF effectiveness depends strongly on host\u0026ndash;fungus compatibility and environmental context (Begum et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Haro et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). In particular, inoculum M3 exhibited high colonization frequency and intensity at 16 months, suggesting sustained symbiotic establishment rather than transient infection.\u003c/p\u003e \u003cp\u003eSustained colonization is especially relevant for woody perennials, where functional benefits of mycorrhization often accumulate over time and contribute to long-term improvements in nutrient acquisition and plant vigor (Smith and Read \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Wu et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Although colonization intensity alone does not guarantee functional benefits, the strong establishment observed for M3 provides a plausible biological basis for its superior performance in subsequent growth and grafting stages.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Effects of AMF inoculation on early seedling growth\u003c/h2\u003e \u003cp\u003eAMF inoculation enhanced early seedling growth under a low-fertility sandy substrate, particularly by increasing collar diameter. This response is consistent with the well-documented role of AMF in improving phosphorus uptake and overall nutrient status under nutrient-limited conditions (Smith and Read \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Wu et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Recent meta-analyses have shown that AMF inoculation generally increases plant biomass and nutrient acquisition, although effect sizes vary depending on inoculum identity and experimental conditions (Wu et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe absence of significant differences in relative growth rates suggests that inoculation effects were expressed primarily through cumulative growth rather than changes in instantaneous growth dynamics. From a nursery perspective, increased collar diameter is particularly relevant, as it reflects improved structural development and potential physiological capacity of the rootstock.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e4.3. AMF inoculation and graft success\u003c/h2\u003e \u003cp\u003eA major outcome of this study is the substantial increase in graft success observed in AMF-inoculated plants, with inoculum M3 achieving markedly higher success rates than uninoculated controls. This finding supports the hypothesis that improving rootstock vigor through biological inoculation can enhance graft establishment in shea, a species known for variable grafting success under nursery conditions (Yao et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eLogistic regression analysis revealed a positive association between collar diameter at grafting and graft success probability. Each 1 mm increase in collar diameter increased the odds of graft success by approximately 38%, although this effect was marginally significant (p\u0026thinsp;=\u0026thinsp;0.091) and the 95% confidence interval slightly overlapped unity. The relationship between collar diameter and graft success should be interpreted as probabilistic rather than deterministic. Collar diameter represents an operational proxy of rootstock vigor, integrating multiple underlying physiological attributes, but does not constitute a direct mechanistic driver of graft union formation. The marginal statistical significance observed in the logistic model suggests that additional, unmeasured factors such as carbohydrate reserves, cambial activity, hormonal balance, or post-grafting microenvironmental conditions likely interact with rootstock size to determine grafting outcomes. This result indicates a biologically meaningful trend, while also highlighting that collar diameter alone does not fully explain grafting outcomes.\u003c/p\u003e \u003cp\u003eSuch a pattern is consistent with grafting physiology, where rootstock vigor, cambial activity and carbohydrate availability contribute to callus formation and vascular reconnection, but interact with additional technical and environmental factors (Hartmann et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The absence of a significant block effect further suggests that grafting conditions were homogeneous and that the observed trend reflects intrinsic plant characteristics rather than experimental artefacts.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e4.4. Collar diameter as a practical, but not exclusive, predictor of graft success\u003c/h2\u003e \u003cp\u003eThe positive trend linking collar diameter to graft success supports the use of this trait as a practical indicator of rootstock quality in nursery operations. Larger collar diameter likely reflects better-developed vascular tissues and greater physiological capacity to support graft union formation (Hartmann et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). However, the marginal statistical significance observed here indicates that collar diameter should be viewed as a contributory factor, rather than a sole determinant of graft success.\u003c/p\u003e \u003cp\u003eThis nuanced interpretation is important for operational recommendations: selecting vigorous rootstocks based on collar diameter can improve grafting efficiency, but optimal outcomes will also depend on grafting technique, scion quality and post-grafting management (Yao et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e4.5. Implications for shea propagation and restoration strategies\u003c/h2\u003e \u003cp\u003eTaken together, the results suggest that targeted inoculation with high-performing indigenous AMF inocula can improve both rootstock vigor and grafting outcomes in \u003cem\u003eVitellaria paradoxa\u003c/em\u003e. While the relationship between collar diameter and graft success is not strictly deterministic, the observed positive trend supports integrating AMF inoculation with morphological selection criteria to enhance nursery efficiency.\u003c/p\u003e \u003cp\u003eGiven the slow juvenile growth of shea and the need to accelerate parkland restoration, such combined strategies could reduce propagation time and losses, provided that benefits persist after field transplantation. Field-level validation across contrasting edaphoclimatic conditions remains a critical next step (Boffa \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e4.6. Limitations and perspectives\u003c/h2\u003e \u003cp\u003eTwo main limitations should be acknowledged. First, the inocula consisted of mixed AMF communities without standardized spore density or taxonomic characterization, limiting mechanistic attribution to specific fungal taxa. Because the study was conducted in non-sterilized soil, the uninoculated control plants were colonized by a background AMF community. Consequently, the observed effects reflect functional differences among indigenous AMF consortia rather than a binary comparison between mycorrhizal and non-mycorrhizal conditions. Second, although collar diameter showed a positive association with graft success, the non-statistical significance indicates that additional physiological or environmental variables likely contribute to grafting outcomes.\u003c/p\u003e \u003cp\u003eFuture research should combine inoculum characterization, physiological measurements of rootstock status and multi-site field trials to refine predictive models of graft success and optimize AMF-based propagation strategies for shea.\u003c/p\u003e \u003cp\u003eIt should be noted that physiological mechanisms potentially underlying graft success, such as carbohydrate reserves, cambial activity or hormonal status of the rootstock, were not directly measured in this study.\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThis study demonstrates that targeted inoculation of \u003cem\u003eVitellaria paradoxa\u003c/em\u003e seedlings with selected indigenous arbuscular mycorrhizal fungi (AMF) can substantially improve nursery performance and grafting outcomes. Among the inocula tested, M3 consistently showed superior performance, combining sustained mycorrhizal colonization, enhanced seedling growth, and the highest graft success rate under nursery conditions.\u003c/p\u003e \u003cp\u003eAMF inoculation significantly increased collar diameter, a key morphological trait associated with rootstock vigor. Binary logistic regression analysis revealed a positive association between collar diameter at grafting and graft success probability, indicating that more vigorous rootstocks tend to exhibit higher graft establishment rates. However, the marginal statistical significance of this relationship suggests that collar diameter should be considered an important contributory factor rather than a sole or deterministic predictor of graft success.\u003c/p\u003e \u003cp\u003eThe strong improvement in graft success observed in AMF-inoculated plants highlights the practical value of integrating biological inoculation strategies with morphological selection criteria in shea nurseries. Such an approach can enhance propagation efficiency, reduce losses during grafting, and shorten the production cycle of graft-ready seedlings.\u003c/p\u003e \u003cp\u003eOverall, these findings support the use of high-performing indigenous AMF inocula as a low-input, ecologically sound strategy to improve shea propagation and contribute to the restoration and rehabilitation of degraded parkland agroforestry systems. Future research should focus on multi-site field validation, long-term performance of inoculated grafted plants, and optimization of inoculation protocols for large-scale nursery application.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of interest\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eZoungrana Abdel Aziz Ben Yaya conducted the nursery experiment, performed data collection, and contributed to data analysis. Haro Hadou conceived and supervised the study, contributed to experimental design, statistical analyses, and led the writing and revision of the manuscript. Tapsoba Madina Alima participated in experimental implementation, data collection, and preliminary analyses.Dianda Mahamadi contributed to the experimental design, provided technical support for mycorrhizal analyses, and critically reviewed the manuscript.All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThis study was made possible through funding provided by the Government of Burkina Faso via the \u0026ldquo;Fonds National de la Recherche et de l'Innovation pour le Dev\u0026eacute;loppement (FONRID)\u0026rdquo;.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAleza K, Wala K, Bayala J, Villamor GB, Dourma M, Atakpama W, Akpagana K (2015) Population structure and regeneration status of \u003cem\u003eVitellaria Paradoxa\u003c/em\u003e (C. F. Gaertner) under different land management regimes in Atacora department, Benin Agroforestry Systems 89:511-523 doi:10.1007/s10457-015-9787-9\u003c/li\u003e\n\u003cli\u003eBegum N et al. (2019) Role of Arbuscular Mycorrhizal Fungi in Plant Growth Regulation: Implications in Abiotic Stress Tolerance Frontiers in Plant Science Volume 10 - 2019 doi:10.3389/fpls.2019.01068\u003c/li\u003e\n\u003cli\u003eBoffa J-M (2015) Opportunities and challenges in the improvement of the shea (\u003cem\u003eVitellaria paradoxa\u003c/em\u003e) resource and its management vol 24. World Agroforestry Centre (ICRAF), Nairobi\u003c/li\u003e\n\u003cli\u003eChandrasekaran M (2020) A Meta-Analytical Approach on Arbuscular Mycorrhizal Fungi Inoculation Efficiency on Plant Growth and Nutrient Uptake Agriculture 10:370\u003c/li\u003e\n\u003cli\u003eEtesami H, Jeong BR, Glick BR (2021) Contribution of Arbuscular Mycorrhizal Fungi, Phosphate\u0026ndash;Solubilizing Bacteria, and Silicon to P Uptake by Plant Frontiers in Plant Science Volume 12 - 2021 doi:10.3389/fpls.2021.699618\u003c/li\u003e\n\u003cli\u003eHaro H, Sanon KB, Le Roux C, Duponnois R, Traor\u0026eacute; AS (2017) Improvement of cowpea productivity by rhizobial and mycorrhizal inoculation in Burkina Faso Symbiosis 74:107-120 doi:10.1007/s13199-017-0478-3\u003c/li\u003e\n\u003cli\u003eHartmann HT, Kester DE, Davies FT, Geneve RL (2011) Plant Propagation: Principles and Practices. Prentice Hall, \u003c/li\u003e\n\u003cli\u003eHoffmann WA, Poorter H (2002) Avoiding bias in calculations of relative growth rate Annals of botany 90:37-42 doi:10.1093/aob/mcf140\u003c/li\u003e\n\u003cli\u003ePhillips JM, Hayman DS (1970) Improved procedures for clearing roots and staining parasitic and vesicular-arbuscular mycorrhizal fungi for rapid assessment of infection Transactions of the British Mycological Society 55:158-161\u003c/li\u003e\n\u003cli\u003eR\u0026aelig;bild A, Hansen UB, Kambou S (2012) Regeneration of Vitellaria paradoxa and Parkia biglobosa in a parkland in Southern Burkina Faso Agroforestry Systems 85:443-453 doi:10.1007/s10457-011-9397-0\u003c/li\u003e\n\u003cli\u003eSmith SE, Read DJ (2008) Mycorrhizal symbiosis. vol ISBN 978-0-12-652840-4. Third edition. Academic press, London\u003c/li\u003e\n\u003cli\u003eTrouvelot A, Kough JL, Gianinazzi-Pearson V, Gianinazzi S (1986) Mesure du taux de mycorhization VA d\u0026rsquo;un syst\u0026egrave;me radiculaire. Recherche de m\u0026eacute;thodes d\u0026rsquo;estimation ayant une signification fonctionnelle Mycorrhizae : physiology and genetics:217-221\u003c/li\u003e\n\u003cli\u003eWu Y, Chen C, Wang G (2024) Inoculation with arbuscular mycorrhizal fungi improves plant biomass and nitrogen and phosphorus nutrients: a meta-analysis BMC plant biology 24:960 doi:10.1186/s12870-024-05638-9\u003c/li\u003e\n\u003cli\u003eYao SDM, Diarrassouba N, Alui KA, et al. (2020) Effect of the grafting method on the recovery and growth of juvenile shea plants grafted in nursery East African Scholars Journal of Agriculture and Life Sciences 3:406-414 doi:10.36349/easjals.2020.v03i12.005\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Arbuscular mycorrhizal fungi, Vitellaria paradoxa, indigenous inocula, Burkina Faso","lastPublishedDoi":"10.21203/rs.3.rs-9199452/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9199452/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cem\u003eVitellaria paradoxa\u003c/em\u003e is a keystone species of West African agroforestry systems, yet its regeneration is constrained by slow juvenile growth and low grafting success. Arbuscular mycorrhizal fungi (AMF) have the potential to enhance seedling vigor, but their contribution to the production of graftable rootstocks remains poorly documented. This study evaluated the effects of six indigenous AMF inocula on mycorrhizal colonization, early growth, and graft success of \u003cem\u003eV. paradoxa\u003c/em\u003e under nursery conditions.\u003c/p\u003e \u003cp\u003eSeedlings were inoculated with six indigenous AMF inocula or left uninoculated as controls. Mycorrhizal colonization was assessed at 9 and 16 months after inoculation, while growth parameters were measured up to 9 months. The plants were then grafted using the terminal cleft grafting technique, and graft success was evaluated 90 days after grafting. The relationship between grafting success rate and plant growth was analysed using binary logistic regression, including collar diameter as a covariate.\u003c/p\u003e \u003cp\u003eMycorrhizal colonization differed markedly among inocula, with M3 and M2 showing the highest colonization frequency and intensity at 16 months. Inoculation significantly enhanced seedling growth, particularly collar diameter, with M1 and M3 producing the most vigorous rootstocks. Graft success was strongly improved by AMF inoculation, reaching 96% with M3 compared to 32% in uninoculated controls. Logistic modeling revealed a positive association between collar diameter and graft success.\u003c/p\u003e \u003cp\u003eThese results demonstrate that targeted inoculation with indigenous AMF inocula can substantially improve the production of graftable shea rootstocks and enhance graft success. Integrating AMF inoculation for vigorous seedlings offers a promising strategy to accelerate shea parkland restoration.\u003c/p\u003e","manuscriptTitle":"Enhancing growth and graft success of shea (Vitellaria paradoxa C.F. Gaertn) through targeted inoculation with indigenous arbuscular mycorrhizal fungi","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-10 13:10:58","doi":"10.21203/rs.3.rs-9199452/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-23T14:09:21+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-20T13:02:30+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-14T09:50:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"127694128237607565267437981302287009912","date":"2026-04-14T08:25:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"307801697065399758997671636312811575939","date":"2026-04-08T13:52:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"156701385464764431149211391419096256495","date":"2026-04-07T10:01:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"13400664987132477322016172720745488963","date":"2026-04-07T09:08:47+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-05T07:23:02+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-05T07:11:57+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-04-03T23:42:38+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-01T13:26:14+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2026-04-01T11:35:59+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"26f1de67-dcdf-4195-b7b4-67621c70170a","owner":[],"postedDate":"April 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":65948542,"name":"Biological sciences/Ecology"},{"id":65948543,"name":"Earth and environmental sciences/Ecology"},{"id":65948544,"name":"Biological sciences/Microbiology"},{"id":65948545,"name":"Biological sciences/Plant sciences"}],"tags":[],"updatedAt":"2026-05-19T12:38:18+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-10 13:10:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9199452","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9199452","identity":"rs-9199452","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}