Different fruit maturity stages and slimy seedcoat affects seed character and germination of horned melon (Cucumis metuliferus E. Mey. Ex. Schrad)

Different fruit maturity stages and slimy seedcoat affects seed character and germination of horned melon (Cucumis metuliferus E. Mey. Ex. Schrad) | 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 Different fruit maturity stages and slimy seedcoat affects seed character and germination of horned melon (Cucumis metuliferus E. Mey. Ex. Schrad) Nelson Mlambo, Marveline Chifamba, Thembilihle Mhlalahayazi, Bridget Mwabvu, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6726974/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Feb, 2026 Read the published version in Scientific Reports → Version 1 posted 13 You are reading this latest preprint version Abstract In the past decade, there has been a significant rise in the consumption of wild collected horned melon ( Cucumis metuliferus ). Commercial production of the crop is growing, yet little information is available on its agronomy. Seed germination experiments were carried out at Midlands State University, to establish the effect of seed maturity at harvest, and the slimy seedcoat on germination of horned melon seed. Seed was manually extracted from fruit harvested at the mature green fruit (MG), colour break stage (CB) and fully ripe (FR) stage. Three replicates of fifteen seeds from each colour group were placed in petri dishes lined with cotton wool, wetted with distilled water and placed in an incubator at 25 ºC. The petri dishes were arranged in a completely randomised design. Seeds from the fully ripe stage had the highest germination percentage (P < 0.05), with germination occurring in the shortest period. This was followed by the colour break (CB) stage. No germination was observed on seed harvested from mature green fruit. In the second experiment, seed harvested from the CB and FR stages were used, with one set of the seed having the slimy seedcoat removed and the second set having the slimy seedcoat intact. Germination was evaluated under laboratory incubation and greenhouse experiments. Removal of the slimy seedcoat improved seed germination in both the laboratory (P < 0.001) and greenhouse pot (P = 0.021) experiments. Significant germination improvement occurred when slimy seedcoat was removed. Biological sciences/Ecology Biological sciences/Plant sciences Wild fruits horned melon kiwano dormancy germination percentage Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Wild fruits, such as horned melon are an integral part of food and nutrition security for communities living closer to forest ecosystems. They contribute to livelihood through the provision of food and nutraceuticals (Sunderland et al. 2013 , Omotayo and Aremu 2020 ). However, very few attempts have been made to augment the forest supply of these wild fruits through domestication and production in home gardens and farmers’ fields (Chacha et al. 2022 , Kunene et al. 2020 ). The horned melon, Cucumis metuliferus , also known as kiwano is an indigenous plant of Africa. It is now cultivated in other parts of the world, albeit as a minor crop. Commercial production is evident in countries like New Zealand, the United States, Kenya, France, Australia, and Israel (Šeregelj et al. 2022). Although Africa is the continent of origin of the horned melon, only a few countries: Sierra Leone and Kenya have started growing the crop commercially (Usman et al. 2015 ). In most countries, including Zimbabwe, the horned melon consumed is collected from the wild, with a few being grown as intercrop in farmers’ fields. The horned melon fruit comes in two forms; the bitter and sweet tasting melon. The sweet tasting melons are consumed as food while the bitter types are not often consumed by humans. The horned melon has various culinary uses, including as a constituent in salads, cocktails, and drinks. It is rich in essential nutrients such as carbohydrates, calcium, iron, and proteins (Usman et al. 2014 , 2015 ). Horned melons are either consumed raw or cooked as a dessert or snacks or processed into juice (Lim 2012; Usman et al. 2014 ). In some communities, horned melon leaves are cooked and eaten as leafy vegetables. Reviews by Usman et al ( 2015 ) and Rani et al. ( 2019 ) identified several medicinal properties of horned melon including culinary, haematological, analgesic, anti-ulcer as well as antiviral properties. The fruit has been reported to have curative effects on various human and livestock diseases, including peptic ulcers, HIV-related infections, hepatitis, malaria as well as diabetes (Amagon et al. 2012 ; Usman et al. 2012; 2014 ). The horned melon fruit has remarkable storability. This attribute makes it a suitable crop for rural communities where post-harvest facilities limit the storage of fleshy produce. Despite the numerous advantages of the horned melon, the crop has not received adequate research attention (Usman et al. 2015 ). For decades, the horned melon has been neglected in its continent of origin, Africa. Few attempts have been made to domesticate or improve it. Currently, there is little research or literature on the production of horned melon in Africa. The introduction of underutilized and orphaned crops like horned melon into mainstream cultivation requires extensive breeding, seed improvement as well as agronomic studies (Adelabu and Franke 2023 ). The understanding of seed biology and germination characteristics is one of the first important steps in commercial production. Currently, there is no commercial seed production for the horned melon, nor are there standard harvesting protocols recommended for seed harvesting. Where attempts have been made to plant it in farmers’ fields, seed is collected from the fruit during consumption. Because melon consumption is done at different ripening stages, seed collection is mostly done when the farmers are eating, regardless of the stage of fruit ripening. No studies have been done yet to show the influence of seed maturity at harvest on germination. The current seed harvesting practice by farmers involves squeezing the seeds out of the fruit and drying them on walls or surfaces. As the seed comes out of the melon upon squeezing, it slides with the slimy seedcoat intact, which dries alongside the seed. After drying the seed is collected and stored ready for planting. As a result, the seed is planted with the slimy mucilaginous covering intact. No studies have been done to show the effect of this mucilage on the germination of horned melons. The current study therefore aimed to establish, first the effect of the seed harvesting stage, and secondly, the effect of slimy seedcoat removal on germination in the laboratory and the soil. Materials and methods Study site. The trials were carried out in 2016 and 2017, in the Horticulture Laboratory and greenhouse at Midlands State University, Zimbabwe (19 o 45 ’ S, 29 o 84 ’ E). Midlands State University is located 10 km southeast of Gweru Central Business District, at an elevation of 1428 m above sea level (Fig. 1 ). The area receives an average annual rainfall of 674 mm, with an annual average mean temperature of 18 o C. Soils at the site are sandy loams belonging to the fersialitic group with kaolinite clay minerals being dominant (Nyamapfene 1991 ). 2.2 Fruit sample sourcing and maturity The fruit used in the study were collected from a supplier at Kudzanayi market, Gweru. A prior supply arrangement was made with supplier from Ngamo communal farming communities (-19.435621; 29.581916), located 35 km outside Gweru town. Fruits were grouped according to three maturity stages, determined by colour (Fig. 2 ). The three colour groups were described as mature green (MG), characterised by fully grown fruit, green in colour with parallel whitish lines running along the length of the fruit and green sharp pointed horns (Fig. 2 ). At the green stage, the petiole holding the fruit is still green. The second maturity stage used in the study is the break stage (CB). Fruit at CB stage is fully developed in size with ground colour starting to turn yellow. The tips of the horns are showing signs of hardening and drying up. The third stage was the fully mature fruit with a fully developed yellow ground colour (FR). The tips of the horns break off and in more advanced maturity stages (when the fruit is completely yellow); the skin of the fruit can peel easily from the fruit. To confirm differences in the three colour groups, physicochemical attributes such as titratable acidity and total soluble solids content of the colour group were determined. Figure 3 Schematic presentation of fruit collection, physicochemical determination, seed characterization, laboratory germination studies and greenhouse pot experiment. A) Mature green stage, (MG) colour break stage, (CB) fully mature stage (FR). Seed from the mature green (MG) stage was not used in experiments 2 and 3 because of zero germination in experiment 1. (Source: Authors’ creation) 2.3 Sample experimentation, testing, and scoring 2.3.1 Determination of fruit physicochemical characters Fruit weight, fruit width and length were measured on each fruit before destructive sampling for soluble solids measurement and seed extraction. Thereafter, fruits were dissected into two halves using a knife. Succulent seeds were squeezed out using hands, and were placed on petri dishes and allowed to dry in the sun for seven days before being stored for three months (Fig. 4 ). Thereafter, germination tests were carried out. The soluble solids composition of individual fruit was measured using a handheld refractometer (RHB-18/ATC, Emulab (Pty), Ltd). 2.3.2 Laboratory germination tests. Seed extracted from the three different fruit maturity groups (MG, CB, and FR) were tested for germination under laboratory conditions. Germination tests were carried out in plastic petri dishes lined with wet cotton wool, in an incubator (Inco Thermal Digital Incubator, United Scientific, South Africa), at 25°C. Briefly, seeds were soaked in water for 48 hours before germination tests were carried out. A total of 15 seeds were placed in a plastic petri dish lined with damp cotton wool. The petri dishes were then placed in the incubator at a temperature of 25˚C. The experiment was laid out as a completely randomised design (CRD) replicated 6 times. Germination was monitored for 12 days, during which period the cotton wool in the petri dishes was continuously wetted using a dropper bottle. Germination was recorded every day after 2 days of incubation up to 12 days. Seeds were considered to have germinated when 1 mm radicle emerged. 2.3.3 Laboratory Experiment 2 A second experiment was carried out to establish the effect of slimy seedcoat removal on the germination of seed from the breaker stage (BS) and the fully ripe (FR) fruit stages. All seeds were soaked in distilled water for 48 hours. One set of seeds was collected with the seed coat intact to simulate direct soil planting. Figure 5 shows the seed encapsulated in the jelly seedcoat. The second half of the seedlot was placed in a small plastic jar, while still immersed in distilled water. The seeds were whisked until all the seed were released from the jell surrounding the seed. Fifteen (15) seeds from each maturity group were placed in the Petri dishes lined with cotton wool, wetted and placed in the incubator. The experiment was arranged as a 2 × 2 factorial experiment in a completely randomised design (CRD), replicated 4 times. Germination was observed from day 6 until day 12. Seeds were considered to have germinated when 1 mm of the radicle had emerged. Table 1 Treatment table for the laboratory and greenhouse pot experiment to test the effect of slimy seedcoat removal on germination of horned melon seed (Authors’ development based on the laboratory experiments and treatments). Treatment Treatment description Treatment 1 Mature green (MG) seed with slimy seedcoat Treatment 2 Mature green (MG) seed without slimy seedcoat Treatment 3 Fully ripe (FR) seed with slimy seedcoat Treatment 4 Fully ripe (FR) seed without slimy seedcoat 2.3.4 Greenhouse germination trials Plastic pots were filled with 10 kg of soil collected from the Midlands State University Campus farm fields and placed in the greenhouse. Fifteen seeds from the two-maturity group were placed in each of the pots according to the treatments in Table 1 . The pots were laid in the greenhouse while arranged in a completely randomised design replicated 3 times. Pots were watered regularly to keep moisture at field capacity. Germination was observed from day 6 until day 12. Seeds were considered to have germinated when the cotyledons were fully emerged from the ground. 2.3.5 Experimental data scoring (Germination percentage, mean germination time and germination index). Germination was defined by the emergence of a 1 mm radicle which was checked starting from 2 days after the seeds have been placed in the incubator at 25 ˚C. The number of seeds that germinated during the course of the experiment was presented as percentages. \(\:\text{G}\text{e}\text{r}\text{m}\text{i}\text{n}\text{a}\text{t}\text{i}\text{o}\text{n}\:\text{p}\text{e}\text{r}\text{c}\text{e}\text{n}\text{t}\text{a}\text{g}\text{e}=\frac{\text{N}\text{i}}{\text{N}}\:\) × 100 Where, N i = number of germinated seed, N = total number of seeds Mean germination time was obtained by looking at the average time period taken by the seeds in each sample to attain their highest germination count (Ranal and Santana 2006). Mean germination time (MGT) = \(\:\frac{\text{n}1\:\times\:\:\text{d}1+\text{n}2\:\times\:\text{d}2+\text{n}3\:\times\:\text{d}3+\dots\:\dots\:\dots\:.}{total\:number\:of\:days}\) MGT = n1 x d1 + n2 x d2 + n3 x d3 + --------/ total number of days Where, n = number of germinated seed, d = number of days Germination rate/ index (GI): GI= \(\:{\sum\:}_{i=1}^{N}\frac{Si}{Di}\) Where, Si = number of germination seeds in each numeration, Di = number of days till nth numeration, n = number of numeration times. 2.4 Data analysis Data collected was subjected to Analysis of Variance (ANOVA) using GenStat Discovery Edition 14. Treatment means were separated using Least the Least Significance Difference test (LSD), at a 5% level of significance. Results 3.1 Physicochemical attributes of fruits The average weight of fruit did not differ significantly due to stages of maturity. The fruit ranged from 138.2 g to 245.1 g, with an average weight of 189.25 g (Table 2). The fruit had an average length of 15.4±0.3 cm and a diameter of 17.9±0.4 cm. The total soluble solids (TSS) content ( 0 Brix) of the horned melon varied with the maturity stage at harvesting (Table 2). The TSS ranged from 1.5% to 6.5%, with fruits from the mature green stage having the least sugar content and the highest being the fully ripe (FR) stage. Table 2 . Physicochemical attributes of horned melon fruits used in the study (Source: Authors’ development based on the analysis of samples) Fruit maturity stage Weight (g) Length (cm) Width (cm) TSS ( 0 Brix) Mature green (MG) 195.2±14.0 15.5±0.2 18.1±0.4 2.0±0.03 Colour Break (FR) 183.8±12.6 15.4±0.2 17.7±0.3 2.94±0.02 Fully ripe (FR) 188.7±29.9 15.34±0.5 17.9±0.4 5.05±0.01 Significance ns ns ns *** The total soluble solids (TSS) increased with the progression of maturity of the fruits. Fruits harvested at the mature green stage had an average of 2.0 0 Brix. The sugar content of fruits harvested at the break stage had an average TSS of 3.0 0 Brix. The highest TSS was observed in the fully ripe fruit (5.1 0 Brix). There are marked differences in the weight of seeds extracted from horned melons from the three maturity stages. Seeds from the fully ripe (FR) fruit had an average weight of 13 g / 1000 seeds. This was followed by seed extracted from colour break (CB) fruit with seed weighing 11.6 g/ 1000 seeds. The seed from the mature green (MG) fruit had the least seed weight, 7.3 g/ 1000 seeds. Seed weight results show progressive filling of seed with ripening as the sugar content increases. 3.2 Effect of seed harvesting stage on the germination of horned melon. Seed germination percentage differed significantly according to the maturity stage (P< 0.05) (Fig. 6) . The mature green stage had no seed that germinated while 13% of the break stage seed germinated by the end of the experiment. The highest germination percentage was recorded on seed extracted from fully ripe (FR) fruit, which had a germination of 56%. 3.3 Effect of fruit harvesting stage on germination rate. The germination percentage of seed from fully mature seed increased from 4% at 3 days to a peak of 56% at 8 days ( Fig. 7 ). Seeds from the fully ripe stage germinated more effectively than those from the CB and MG stages. FB indicated a gradual increase in germination percentage over time, fully ripe seeds increased significantly after about 5 days and levelled off at around 56% by day 8. CB showed a steady slow rate of germination compared to fully ripe which levelled off around 10% by day 10. 3.4 Effect of slimy seed coat removal and seed maturity on the germination of horned melon seed. Results showed no interaction between stages of seed harvesting and slimy seedcoat removal (P = 0.331). Seed harvesting stages did not result in significant differences in the germination of horned melon seed. However, significant improvement in seed germination occurred when the slimy seedcoat was removed (P = 0.001). Seed with intact slimy seedcoat had a germination percentage of 59.2%, which was 27.5% lower than seed with seed coat removed, with 86.7% germination ( Table 3). Table 3 . Effect of slimy seedcoat removal and stage of seed harvesting on germination percentage of horned melon seed in the laboratory experiment (Source: Authors’ development based on the analysis of samples). In the pot experiment, there was no interaction between stages of seed maturity at harvest and slimy seedcoat removal on seed germination (P = 0.284). The seed harvesting stage did not result in significant differences in the germination of horned melon seed. The removal of the slimy seedcoat led to an improvement in seed germination (P = 0.010) ( Table 4 ). Table 4 . Effect of gel removal and stage of seed harvesting on germination percentage of horned melon seed in the pot experiment (Source: Authors’ development based on the analysis of samples) . New and emerging crops are essential in ensuring food security and meeting future food demands (Poltenen-Sainio et al. 2011; Okigbo and Ugwu 2021). Their introduction to mainstream cultivation should, be preceded by comprehensive studies on breeding, agronomy, and crop protection. A reliable seed system needs to be developed for these to supply growers with reliable seeds (Hampton et al. 2013; Adelabu and Franke 2023). The current studies looked at the morpho-physiological characteristics of horned melon seed harvested at three different fruit maturity stages. The study demonstrated that the total soluble solid composition of horned melon pulp increased from the mature green fruit to the fully ripe fruit. The increase in sugar content from the mature green to the break colour was in the order of 47% while the increase from the broken colour to the fully mature was 106%. The fully ripe fruit contained 153% more soluble solids compared to the mature green (MG) fruit. Seed weight (1000 seed weight) increased with the stage of ripening, with the least weight observed in mature green fruit. Seed weight in cucumber ( Cucumis sativus L.) increases with late fruit harvest as well as fruit storage duration after harvest (Pathania et al. 2022). This phenomenon could be true of the horned melon fruit, as results indicate a marked increase in seed weight, consequent with ripening. These results suggest that seed filling and embryo development in melons starts immediately before the break stage, progressing through to the fully matured fruit and possibly in storage. The quality of seed is a key component of crop production (Gupta et al. 2021). It determines the germination percentage, vigour and eventual crop stand. Thus, optimising seed harvesting is key to the production of good-quality seeds (Passam et al. 2010). In our study, the highest number of germinated seeds in the lot was extracted from fully mature fruit, followed by seed extracted from fruit harvested at colour break stage. Seed extracted from the mature green fruit showed no signs of germination after 12 days of monitoring. While for most salad lovers, the eating quality could be best at the mature green stage, the seed at this stage is immature, and will not germinate. Overall, the germination percentage for all maturity stages was found to be generally low when compared with seed industry requirements, which set the minimum germination percentage closer to 100% for a seed lot (Hampton et al. 2013). We, therefore, presumed that another factor could be at play in reducing overall germination percentage even for the stages that germinated. Further experiments were thus carried out to ascertain if the presence of the slimy seedcoat around the seed could have prevented many of the seeds from germinating. In the second and third experiments, the influence of slimy seedcoat on horned melon seed germination was assessed in laboratory and greenhouse pot experiments. Removing the seed coating resulted in a significant improvement in seed germination. Seeds whose slimy seedcoat was removed showed higher germination on 6 th day when compared with seeds with the slimy seedcoat intact. Germination progressed to peak on 9 th day with seed extracted from mature yellow fruit peaking at 91% for the coatless seed and 75% germination for the seed with slimy seedcoat intact. Further, the two experiments revealed that germination increased from 59% in the laboratory experiment to 75% in the soil. It was also noted that the speed of germination was faster in the soil than in the petri dishes. Seed lot germination is dependent on the age of the seed, seed pre-treatment, and germination conditions (Thompson et al. 1993). The study showed that, the gel surrounding the horned melon seed provide a second barrier to germination which needs to be broken, for optimum germination to occur. This could be an adaptation measure by the horned melon seed to prevent germination in the wild, when no sufficient rains have been received. The coat stays wrapping the seed and will need soil microbial processes to be broken down. However, the increase in germination in the soil is comparatively small for commercial production. Conclusions The current study aimed to understand horned melon seed maturation for seed harvesting. The study established that the stage of fruit harvesting influenced the germination capability of the seed. The mature green fruit, which is often eaten as salad was shown to produce a seed that is light (measured by 1000 seed weight), was immature and did not germinate. Fruit harvested at the break colour produces a seed that has comparatively better seed weight with improved germination. The best germination was observed in seeds harvested from fully ripe fruit. The study further revealed that; germination is impeded by the presence of a slimy seedcoat surrounding the seed. The seed of a horned melon is enclosed in a slimy seedcoat which prevents early seed germination. Thus, the study recommends seed harvesting from fruit that has matured at least to the colour break stage, and the removal of slimy seedcoat covering during seed processing to ensure optimum germination. To the best of our knowledge, this is one of the few studies (especially in Africa) that reveal the significant effects, benefits, and influence of horned melon and how they could be critical for food security and nutrition. Declarations Funding The research was partly funded by the Innovation Fund of the Midlands State University Research Board. Author contributions Tavagwisa Muziri : Conceptualisation, Methodology, Supervision, Software Nelson Mlambo : Investigation, Writing – original draft preparation Chifamba Marveline : Validation, Software- validation, Thembilihle Mhlahlayazi : Laboratory - validation, Bridget Mwabvu : Writing – reviewing and editing, Investigation -validation, visualisation Ignatious Chagonda : Investigation, Writing – reviewing and editing, Tendayi Madanzi : Writing – reviewing and editing, Marjory RuvimboTakawira : Investigation- laboratory techniques. All authors reviewed the manuscript. Acknowledgements This study benefited from studies done by the following students: Nelson Mlambo, Thembilihle Mhlahlayazi and Marvelline Chifamba, for the partial fulfilment of their BSc Horticulture Degrees. Equipment and facilities to carry out this research were availed by the departments of Horticulture and Agronomy as well as the Department of Agriculture Practice of the Midlands State University. The authors are sincerely grateful for this support. References Adelabu, D. B. & Franke, A. C. Status of underutilized crop production: Its potential for mitigating foof insecurity. Agron. J. 115 , 2174–2193 (2023). Amagon, K. I., Wannang, N. N., Ior, L. & Chris-Otubor, B. O. Flavonids extracted from fruit pulp of Cucumis metuliferus have antiviral properties. J. Pharm. Res. Int. 2 (4), 249–258 (2012). Chacha, J. S. et al. Chapter 7 – Underutilised fruits: Challenges and constraints for domestication, Editor(s): Rajeev Bhat, Future Foods. Academic Press. 133–150. ISBN 9780323910019. (2022). https://doi.org/10.20546/ijcmas.2021.1001.245 Gupta, N. et al. Challenges and opportunities in cucumber seed production. Int. J. Cur Microbiol. Appl. 10 (01), 2135–2144. https://doi.org/10.20546/ijcmas.2021.1001.245 (2021). Hampton, J. G., Boelt, B., Rolston, M. P. & Chstain, T. G. Effects of elevated CO2 and temperature on seed quality. J. Agric. Sci. 151 , 154–162. 10.1017/S0021859612000263 (2013). Kunene, E. N., Nxumalo, K. A., Ngwenya, M. P. & Masarirambi, M. T. Domesticating and commercialization of indigenous fruit and nut tree crops for food security and income generation in the Kingdom of Eswatini. Curr. Appl. Sci. Technol. 39 (16), 37–52 (2020). Mendlinger, S., Benzioni, A., Hyskens, S. & Ventura, M. Fruit development and postharvest physiology of Cucumis metuliferus Mey: a new crop plant. J. Hortic. Sci. 67 (4), 489–493 (2015). Nkosi, N. N., Mostert, T. H. C. V., Dzikiti, S. & Ntuli, N. R. Prioritisation of indigenous tree species with domestication and commercialization potential in KwaZulu Natal, South Africa. Genetic Resour. Crop Evol. 67 , 1567–1575 (2020). Nyamapfene, K. The Soils of Zimbabwe. Nehanda Publishers. Harare. Zimbabwe.pp179. (1991). Okigbo, R. N. & Ugwu, C. S. Neglected crops of Africa. Int. J. Agric. Technol. 17 (6), 2197–2210 (2021). Omotayo, O. A. & Aremu, A. O. Underutilised Africa indigenous fruit trees and food nutrition security: Opportunities, challenges, and prospects. Food Energy Secur. 9 (3), 220. https://doi.org/10.1002/fes3.220 (2020). Passam, H. C., Theodoropoulou, S., Karanissa, T. & Karapanos, I. C. Influence of harvest time and after ripening on the seed quality of eggplanty. Sci. Hortic. 25 (3), 518–520. https://doi.org/10.1016/j.scienta.2010.04007 (2010). Pathania, K., Kaur, N., Kaur, D. & Singh, R. Mobilisation of fruit pulp reserves towards seeds in Cucumber (Cucumis sativas L.) fruit harvested at variable developmental stages. Plant. Physiol. Rep. 27 (2), 268–274 (2022). Pelronen-Saini, P., Rajala, A. & Jauhiainen, L. Hidden viability risks in the use of farm-saved small grain seed. J. Agric. Sci. 149 (6), 713–724. 10.1017/S0021859611000335 (2001). Rani, B. et al. Incredible benefits of exotic Kiwano (Horned melon) for wellness, vigor and vitality. IJBI 1 (2), 56–59. https://doi.org/10.46505/IJBI.2019.1204 (2019). Sunderland, T. et al. Food Security and Nutrition. The Role of Forests. Discussion Paper. SIFOR. Bongor, Indonesia. (2013). Thompson, A. J. & EL-Kassaby, T. M. Interpretation of seed-germination parameters. New. For. 7 , 123–132 (1993). Usman, J. G., Sodipo, O. A., Kwaghe, A. V. & Sandabe, U. K. Uses of Cucumis metuliferus: A review. Cancer Biol. 5 (1), 25–34 (2015). Usman, J. G., Sodipo, O. A. & Sandape, U. K. Phytochemical screening and acute toxicity study of Cucumis metuliferus e. mev, Ex. Naudin fruit extracts in cockrels. Int. J. Phytomed . 6 (2), 243–247 (2014). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 28 Feb, 2026 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 18 Sep, 2025 Reviews received at journal 17 Sep, 2025 Reviews received at journal 10 Sep, 2025 Reviewers agreed at journal 28 Aug, 2025 Reviewers agreed at journal 27 Aug, 2025 Reviewers agreed at journal 02 Jul, 2025 Reviews received at journal 19 Jun, 2025 Reviewers agreed at journal 19 Jun, 2025 Reviewers invited by journal 18 Jun, 2025 Editor invited by journal 29 May, 2025 Editor assigned by journal 27 May, 2025 Submission checks completed at journal 25 May, 2025 First submitted to journal 22 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6726974","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":474290927,"identity":"8e9d9973-0656-43b1-846c-c3aef004ff14","order_by":0,"name":"Nelson Mlambo","email":"","orcid":"","institution":"Midlands State University","correspondingAuthor":false,"prefix":"","firstName":"Nelson","middleName":"","lastName":"Mlambo","suffix":""},{"id":474290928,"identity":"21536cdc-b8b8-44d0-9862-5d29b97639bb","order_by":1,"name":"Marveline Chifamba","email":"","orcid":"","institution":"Midlands State University","correspondingAuthor":false,"prefix":"","firstName":"Marveline","middleName":"","lastName":"Chifamba","suffix":""},{"id":474290929,"identity":"693650fc-1aec-4e0c-b062-66e84b13b062","order_by":2,"name":"Thembilihle Mhlalahayazi","email":"","orcid":"","institution":"Midlands State University","correspondingAuthor":false,"prefix":"","firstName":"Thembilihle","middleName":"","lastName":"Mhlalahayazi","suffix":""},{"id":474290930,"identity":"ccdfcd0d-8d5c-4361-b63d-50494f4504e5","order_by":3,"name":"Bridget Mwabvu","email":"","orcid":"","institution":"Midlands State University","correspondingAuthor":false,"prefix":"","firstName":"Bridget","middleName":"","lastName":"Mwabvu","suffix":""},{"id":474290931,"identity":"0e2f1d38-ff1d-417c-95a8-6458e1ea0ef5","order_by":4,"name":"Ignatius Chagonda","email":"","orcid":"","institution":"Midlands State University","correspondingAuthor":false,"prefix":"","firstName":"Ignatius","middleName":"","lastName":"Chagonda","suffix":""},{"id":474290932,"identity":"fe4d67cd-6ec5-4b7c-a12c-24f1b0e27da6","order_by":5,"name":"Tendai Madanzi","email":"","orcid":"","institution":"Midlands State University","correspondingAuthor":false,"prefix":"","firstName":"Tendai","middleName":"","lastName":"Madanzi","suffix":""},{"id":474290933,"identity":"70e1e43a-0c6c-4ca5-914a-e152f3607cce","order_by":6,"name":"Marjory Ruvimbo Takawira","email":"","orcid":"","institution":"Midlands State University","correspondingAuthor":false,"prefix":"","firstName":"Marjory","middleName":"Ruvimbo","lastName":"Takawira","suffix":""},{"id":474290934,"identity":"0f2e5877-5cf7-43ea-9ce7-fcb3579a6548","order_by":7,"name":"Tavagwisa Muziri","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAu0lEQVRIiWNgGAWjYLCCBAYJOeJV80C1GJOoBQgSG4jWYi92xvjDwz0W6RtuJD9g+FHDYG9wgJAt0jkGBgnPJHI33EgzYOw5xsBMlJaEhAMSudtuJBgw8DYwsJkRo+UAUEu62Y30D4x/Gxh4iNFi2ADUkmB2I8eAGWiLBGEtt9OKGYBaDPefeVNwWOaYhIE9IS3ss5M3f/xxoE5esj1948M3NTb2kg0EtKAAoPkSpKgfBaNgFIyCUYALAABpFzvMuvEi7wAAAABJRU5ErkJggg==","orcid":"","institution":"Midlands State University","correspondingAuthor":true,"prefix":"","firstName":"Tavagwisa","middleName":"","lastName":"Muziri","suffix":""}],"badges":[],"createdAt":"2025-05-22 17:08:23","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6726974/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6726974/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-026-40932-6","type":"published","date":"2026-02-28T15:59:01+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":85201248,"identity":"2df4c67e-ba75-4868-9759-8c0e294ef7a7","added_by":"auto","created_at":"2025-06-23 10:25:41","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":116494,"visible":true,"origin":"","legend":"\u003cp\u003eStudy location (Source: Authors’ creation)\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6726974/v1/399f121b451ab1e94fbc1713.jpg"},{"id":85201249,"identity":"50cfc8d3-7d2c-4424-8b9d-8ac60f107564","added_by":"auto","created_at":"2025-06-23 10:25:41","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":86982,"visible":true,"origin":"","legend":"\u003cp\u003eThree different stages of maturity of horned melon were collected from the Kudzanayi market, Gweru, Zimbabwe. The three colour groups were mature green (MG-\u003cstrong\u003eA\u003c/strong\u003e), break stage when the yellow colour starts to show (BS - \u003cstrong\u003eB\u003c/strong\u003e) and fully ripe stage (FR -\u003cstrong\u003eC\u003c/strong\u003e). (Source: Authors’ development).\u003c/p\u003e","description":"","filename":"Picture2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6726974/v1/3eef176ce53b233e5008abe2.jpg"},{"id":85201445,"identity":"a4f3202e-8555-443e-bc40-07ba17cea527","added_by":"auto","created_at":"2025-06-23 10:33:41","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":120830,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic presentation of fruit collection, physicochemical determination, seed characterization, laboratory germination studies and greenhouse pot experiment. A) Mature green stage, (MG) colour break stage, (CB) fully mature stage (FR). Seed from the mature green (MG) stage was not used in experiments 2 and 3 because of zero germination in experiment 1. (Source: Authors’ creation)\u003c/p\u003e","description":"","filename":"Picture3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6726974/v1/f3106dd6298087236ed91467.jpg"},{"id":85201255,"identity":"eab646e4-826a-4158-958b-aa82887613ba","added_by":"auto","created_at":"2025-06-23 10:25:41","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":220751,"visible":true,"origin":"","legend":"\u003cp\u003eSeed extracted from the three maturity stages of horned melon and sun-dried in Petri dishes. Seed extracted from the fully mature (FR) stage (A), seed extracted from the break (CB) stage (B) and seed extracted from the mature green (MG) stage (C). (Source: Authors’ development)\u003c/p\u003e","description":"","filename":"Picture4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6726974/v1/a4991551da8019b0ce3264d4.jpg"},{"id":85201252,"identity":"744e6936-8852-4b86-8466-6fe2663d61b8","added_by":"auto","created_at":"2025-06-23 10:25:41","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":122911,"visible":true,"origin":"","legend":"\u003cp\u003eHorned melon seed encapsulated in a seed jell. The seed jell is impermeable to water, protecting the seed from premature germination (Source: Authors’ development from the Lab experiments)\u003c/p\u003e","description":"","filename":"Picture5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6726974/v1/8ca8c5c2346b7f0ba12386d7.jpg"},{"id":85201254,"identity":"f04efe3b-8559-427c-a1b8-5975f4af81cc","added_by":"auto","created_at":"2025-06-23 10:25:41","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":117203,"visible":true,"origin":"","legend":"\u003cp\u003eGermination percentage of horned melon seeds from fruits harvested at different maturity stages. The three maturity stages were the mature green (MG) stage, the colour break (CB) stage and the fully ripe (FR) stage (Source: Authors’ development based on the analysis of samples)\u003c/p\u003e","description":"","filename":"Picture6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6726974/v1/85cc276f394f1262afe40bec.jpg"},{"id":85201258,"identity":"dbbf7855-417c-4832-8ab6-38fdcef200c1","added_by":"auto","created_at":"2025-06-23 10:25:41","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":143088,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of stage of maturity and seed soaking on germination rate over a period of 12 days (Source: Authors’ development based on the analysis of samples).\u003c/p\u003e","description":"","filename":"Picture7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6726974/v1/c6942c21d2d0da570ac71b4e.jpg"},{"id":103765745,"identity":"14776fab-5a5e-4ce1-b5ff-a047e1a4e3d4","added_by":"auto","created_at":"2026-03-02 16:08:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1767585,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6726974/v1/ff3e0345-a264-46e5-aab1-d96dc5a0c0d4.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Different fruit maturity stages and slimy seedcoat affects seed character and germination of horned melon (Cucumis metuliferus E. Mey. Ex. Schrad)","fulltext":[{"header":"Introduction","content":"\u003cp\u003eWild fruits, such as horned melon are an integral part of food and nutrition security for communities living closer to forest ecosystems. They contribute to livelihood through the provision of food and nutraceuticals (Sunderland et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2013\u003c/span\u003e, Omotayo and Aremu \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). However, very few attempts have been made to augment the forest supply of these wild fruits through domestication and production in home gardens and farmers\u0026rsquo; fields (Chacha et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2022\u003c/span\u003e, Kunene et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The horned melon, \u003cem\u003eCucumis metuliferus\u003c/em\u003e, also known as kiwano is an indigenous plant of Africa. It is now cultivated in other parts of the world, albeit as a minor crop. Commercial production is evident in countries like New Zealand, the United States, Kenya, France, Australia, and Israel (Šeregelj et al. 2022). Although Africa is the continent of origin of the horned melon, only a few countries: Sierra Leone and Kenya have started growing the crop commercially (Usman et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). In most countries, including Zimbabwe, the horned melon consumed is collected from the wild, with a few being grown as intercrop in farmers\u0026rsquo; fields.\u003c/p\u003e \u003cp\u003eThe horned melon fruit comes in two forms; the bitter and sweet tasting melon. The sweet tasting melons are consumed as food while the bitter types are not often consumed by humans. The horned melon has various culinary uses, including as a constituent in salads, cocktails, and drinks. It is rich in essential nutrients such as carbohydrates, calcium, iron, and proteins (Usman et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2014\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Horned melons are either consumed raw or cooked as a dessert or snacks or processed into juice (Lim 2012; Usman et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). In some communities, horned melon leaves are cooked and eaten as leafy vegetables. Reviews by Usman et al (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) and Rani et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) identified several medicinal properties of horned melon including culinary, haematological, analgesic, anti-ulcer as well as antiviral properties. The fruit has been reported to have curative effects on various human and livestock diseases, including peptic ulcers, HIV-related infections, hepatitis, malaria as well as diabetes (Amagon et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Usman et al. 2012; \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2014\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe horned melon fruit has remarkable storability. This attribute makes it a suitable crop for rural communities where post-harvest facilities limit the storage of fleshy produce. Despite the numerous advantages of the horned melon, the crop has not received adequate research attention (Usman et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). For decades, the horned melon has been neglected in its continent of origin, Africa. Few attempts have been made to domesticate or improve it. Currently, there is little research or literature on the production of horned melon in Africa.\u003c/p\u003e \u003cp\u003eThe introduction of underutilized and orphaned crops like horned melon into mainstream cultivation requires extensive breeding, seed improvement as well as agronomic studies (Adelabu and Franke \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). The understanding of seed biology and germination characteristics is one of the first important steps in commercial production. Currently, there is no commercial seed production for the horned melon, nor are there standard harvesting protocols recommended for seed harvesting. Where attempts have been made to plant it in farmers\u0026rsquo; fields, seed is collected from the fruit during consumption. Because melon consumption is done at different ripening stages, seed collection is mostly done when the farmers are eating, regardless of the stage of fruit ripening. No studies have been done yet to show the influence of seed maturity at harvest on germination.\u003c/p\u003e \u003cp\u003eThe current seed harvesting practice by farmers involves squeezing the seeds out of the fruit and drying them on walls or surfaces. As the seed comes out of the melon upon squeezing, it slides with the slimy seedcoat intact, which dries alongside the seed. After drying the seed is collected and stored ready for planting. As a result, the seed is planted with the slimy mucilaginous covering intact. No studies have been done to show the effect of this mucilage on the germination of horned melons. The current study therefore aimed to establish, first the effect of the seed harvesting stage, and secondly, the effect of slimy seedcoat removal on germination in the laboratory and the soil.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eStudy site.\u003c/b\u003e \u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eThe trials were carried out in 2016 and 2017, in the Horticulture Laboratory and greenhouse at Midlands State University, Zimbabwe (19\u003csup\u003eo\u003c/sup\u003e 45\u003csup\u003e\u0026rsquo;\u003c/sup\u003e S, 29\u003csup\u003eo\u003c/sup\u003e 84\u003csup\u003e\u0026rsquo;\u003c/sup\u003e E). Midlands State University is located 10 km southeast of Gweru Central Business District, at an elevation of 1428 m above sea level (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The area receives an average annual rainfall of 674 mm, with an annual average mean temperature of 18 \u003csup\u003eo\u003c/sup\u003eC. Soils at the site are sandy loams belonging to the fersialitic group with kaolinite clay minerals being dominant (Nyamapfene \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1991\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Fruit sample sourcing and maturity\u003c/h2\u003e \u003cp\u003eThe fruit used in the study were collected from a supplier at Kudzanayi market, Gweru. A prior supply arrangement was made with supplier from Ngamo communal farming communities (-19.435621; 29.581916), located 35 km outside Gweru town. Fruits were grouped according to three maturity stages, determined by colour (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The three colour groups were described as mature green (MG), characterised by fully grown fruit, green in colour with parallel whitish lines running along the length of the fruit and green sharp pointed horns (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). At the green stage, the petiole holding the fruit is still green. The second maturity stage used in the study is the break stage (CB). Fruit at CB stage is fully developed in size with ground colour starting to turn yellow. The tips of the horns are showing signs of hardening and drying up. The third stage was the fully mature fruit with a fully developed yellow ground colour (FR). The tips of the horns break off and in more advanced maturity stages (when the fruit is completely yellow); the skin of the fruit can peel easily from the fruit. To confirm differences in the three colour groups, physicochemical attributes such as titratable acidity and total soluble solids content of the colour group were determined.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e Schematic presentation of fruit collection, physicochemical determination, seed characterization, laboratory germination studies and greenhouse pot experiment. A) Mature green stage, (MG) colour break stage, (CB) fully mature stage (FR). Seed from the mature green (MG) stage was not used in experiments 2 and 3 because of zero germination in experiment 1. (Source: Authors\u0026rsquo; creation)\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e2.3 Sample experimentation, testing, and scoring\u003c/h3\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3.1 Determination of fruit physicochemical characters\u003c/h2\u003e \u003cp\u003eFruit weight, fruit width and length were measured on each fruit before destructive sampling for soluble solids measurement and seed extraction. Thereafter, fruits were dissected into two halves using a knife. Succulent seeds were squeezed out using hands, and were placed on petri dishes and allowed to dry in the sun for seven days before being stored for three months (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Thereafter, germination tests were carried out. The soluble solids composition of individual fruit was measured using a handheld refractometer (RHB-18/ATC, Emulab (Pty), Ltd).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003e2.3.2 Laboratory germination tests.\u003c/em\u003e \u003c/p\u003e \u003cp\u003eSeed extracted from the three different fruit maturity groups (MG, CB, and FR) were tested for germination under laboratory conditions. Germination tests were carried out in plastic petri dishes lined with wet cotton wool, in an incubator (Inco Thermal Digital Incubator, United Scientific, South Africa), at 25\u0026deg;C. Briefly, seeds were soaked in water for 48 hours before germination tests were carried out. A total of 15 seeds were placed in a plastic petri dish lined with damp cotton wool. The petri dishes were then placed in the incubator at a temperature of 25˚C. The experiment was laid out as a completely randomised design (CRD) replicated 6 times. Germination was monitored for 12 days, during which period the cotton wool in the petri dishes was continuously wetted using a dropper bottle. Germination was recorded every day after 2 days of incubation up to 12 days. Seeds were considered to have germinated when 1 mm radicle emerged.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e2.3.3 Laboratory Experiment 2\u003c/h3\u003e\n\u003cp\u003eA second experiment was carried out to establish the effect of slimy seedcoat removal on the germination of seed from the breaker stage (BS) and the fully ripe (FR) fruit stages. All seeds were soaked in distilled water for 48 hours. One set of seeds was collected with the seed coat intact to simulate direct soil planting. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the seed encapsulated in the jelly seedcoat. The second half of the seedlot was placed in a small plastic jar, while still immersed in distilled water. The seeds were whisked until all the seed were released from the jell surrounding the seed. Fifteen (15) seeds from each maturity group were placed in the Petri dishes lined with cotton wool, wetted and placed in the incubator. The experiment was arranged as a 2 \u0026times; 2 factorial experiment in a completely randomised design (CRD), replicated 4 times. Germination was observed from day 6 until day 12. Seeds were considered to have germinated when 1 mm of the radicle had emerged.\u003c/p\u003e \u003cp\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\u003eTreatment table for the laboratory and greenhouse pot experiment to test the effect of slimy seedcoat removal on germination of horned melon seed (Authors\u0026rsquo; development based on the laboratory experiments and treatments).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTreatment description\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatment 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMature green (MG) seed with slimy seedcoat\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatment 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMature green (MG) seed without slimy seedcoat\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatment 3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFully ripe (FR) seed with slimy seedcoat\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatment 4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFully ripe (FR) seed without slimy seedcoat\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003e2.3.4 Greenhouse germination trials\u003c/h3\u003e\n\u003cp\u003ePlastic pots were filled with 10 kg of soil collected from the Midlands State University Campus farm fields and placed in the greenhouse. Fifteen seeds from the two-maturity group were placed in each of the pots according to the treatments in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The pots were laid in the greenhouse while arranged in a completely randomised design replicated 3 times. Pots were watered regularly to keep moisture at field capacity. Germination was observed from day 6 until day 12. Seeds were considered to have germinated when the cotyledons were fully emerged from the ground.\u003c/p\u003e \u003cp\u003e \u003cem\u003e2.3.5 Experimental data scoring (Germination percentage, mean germination time and germination index).\u003c/em\u003e \u003c/p\u003e \u003cp\u003eGermination was defined by the emergence of a 1 mm radicle which was checked starting from 2 days after the seeds have been placed in the incubator at 25 ˚C. The number of seeds that germinated during the course of the experiment was presented as percentages.\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:\\text{G}\\text{e}\\text{r}\\text{m}\\text{i}\\text{n}\\text{a}\\text{t}\\text{i}\\text{o}\\text{n}\\:\\text{p}\\text{e}\\text{r}\\text{c}\\text{e}\\text{n}\\text{t}\\text{a}\\text{g}\\text{e}=\\frac{\\text{N}\\text{i}}{\\text{N}}\\:\\)\u003c/span\u003e \u003c/span\u003e\u0026times; 100\u003c/p\u003e \u003cp\u003eWhere, N\u003cem\u003ei\u003c/em\u003e\u0026thinsp;=\u0026thinsp;number of germinated seed, N\u0026thinsp;=\u0026thinsp;total number of seeds\u003c/p\u003e \u003cp\u003eMean germination time was obtained by looking at the average time period taken by the seeds in each sample to attain their highest germination count (Ranal and Santana 2006).\u003c/p\u003e \u003cp\u003eMean germination time (MGT) = \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\frac{\\text{n}1\\:\\times\\:\\:\\text{d}1+\\text{n}2\\:\\times\\:\\text{d}2+\\text{n}3\\:\\times\\:\\text{d}3+\\dots\\:\\dots\\:\\dots\\:.}{total\\:number\\:of\\:days}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003cp\u003eMGT\u0026thinsp;=\u0026thinsp;n1 x d1\u0026thinsp;+\u0026thinsp;n2 x d2\u0026thinsp;+\u0026thinsp;n3 x d3 + --------/ total number of days\u003c/p\u003e \u003cp\u003eWhere, n\u0026thinsp;=\u0026thinsp;number of germinated seed, d\u0026thinsp;=\u0026thinsp;number of days\u003c/p\u003e \u003cp\u003eGermination rate/ index (GI):\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eGI= \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\sum\\:}_{i=1}^{N}\\frac{Si}{Di}\\)\u003c/span\u003e\u003c/span\u003e\u003c/h2\u003e \u003cp\u003eWhere, Si\u0026thinsp;=\u0026thinsp;number of germination seeds in each numeration, Di\u0026thinsp;=\u0026thinsp;number of days till nth numeration, n\u0026thinsp;=\u0026thinsp;number of numeration times.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e2.4 Data analysis\u003c/h3\u003e\n\u003cp\u003eData collected was subjected to Analysis of Variance (ANOVA) using GenStat Discovery Edition 14. Treatment means were separated using Least the Least Significance Difference test (LSD), at a 5% level of significance.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e3.1 Physicochemical attributes of fruits\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe average weight of fruit did not differ significantly due to stages of maturity. The fruit ranged from 138.2 g to 245.1 g, with an average weight of 189.25 g (Table 2). \u0026nbsp;The fruit had an average length of 15.4\u0026plusmn;0.3 cm and a diameter of 17.9\u0026plusmn;0.4 cm. \u0026nbsp;The total soluble solids (TSS) content (\u003csup\u003e0\u003c/sup\u003eBrix) of the horned melon varied with the maturity stage at harvesting (Table 2). The TSS ranged from 1.5% to 6.5%, with fruits from the mature green stage having the least sugar content and the highest being the fully ripe (FR) stage.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eTable 2\u003c/em\u003e. Physicochemical attributes of horned melon fruits used in the study (Source: Authors\u0026rsquo; development based on the analysis of samples)\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"600\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.1667%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFruit maturity stage\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.8333%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWeight (g)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLength (cm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWidth (cm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTSS (\u003csup\u003e0\u003c/sup\u003eBrix)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.1667%;\"\u003e\n \u003cp\u003eMature green (MG)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.8333%;\"\u003e\n \u003cp\u003e195.2\u0026plusmn;14.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e15.5\u0026plusmn;0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e18.1\u0026plusmn;0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e2.0\u0026plusmn;0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.1667%;\"\u003e\n \u003cp\u003eColour Break (FR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.8333%;\"\u003e\n \u003cp\u003e183.8\u0026plusmn;12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e15.4\u0026plusmn;0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e17.7\u0026plusmn;0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e2.94\u0026plusmn;0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.1667%;\"\u003e\n \u003cp\u003eFully ripe (FR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.8333%;\"\u003e\n \u003cp\u003e188.7\u0026plusmn;29.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e15.34\u0026plusmn;0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e17.9\u0026plusmn;0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e5.05\u0026plusmn;0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.1667%;\"\u003e\n \u003cp\u003eSignificance\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 14.8333%;\"\u003e\n \u003cp\u003ens\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003ens\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003ens\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20%;\"\u003e\n \u003cp\u003e***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe total soluble solids (TSS) increased with the progression of maturity of the fruits. \u0026nbsp;Fruits harvested at the mature green stage had an average of 2.0 \u003csup\u003e0\u003c/sup\u003e Brix. \u0026nbsp;The sugar content of fruits harvested at the break stage had an average TSS of 3.0 \u003csup\u003e0\u003c/sup\u003e Brix. The highest TSS was observed in the fully ripe fruit (5.1 \u003csup\u003e0\u003c/sup\u003e Brix). There are marked differences in the weight of seeds extracted from horned melons from the three maturity stages. Seeds from the fully ripe (FR) fruit had an average weight of 13 g / 1000 seeds. This was followed by seed extracted from colour break (CB) fruit with seed weighing 11.6 g/ 1000 seeds. The seed from the mature green (MG) fruit had the least seed weight, 7.3 g/ 1000 seeds. Seed weight results show progressive filling of seed with ripening as the sugar content increases.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2 Effect of seed harvesting stage on the germination of horned melon.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSeed germination percentage differed significantly according to the maturity stage (P\u0026lt; 0.05) \u003cem\u003e(Fig. 6)\u003c/em\u003e. The mature green stage had no seed that germinated while 13% of the break stage seed germinated by the end of the experiment. The highest germination percentage was recorded on seed extracted from fully ripe (FR) fruit, which had a germination of 56%.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3 Effect of fruit harvesting stage on germination rate.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe germination percentage of seed from fully mature seed increased from 4% at 3 days to a peak of 56% at 8 days (\u003cem\u003eFig. 7\u003c/em\u003e). Seeds from the fully ripe stage germinated more effectively than those from the CB and MG stages. FB indicated a gradual increase in germination percentage over time, fully ripe seeds increased significantly after about 5 days and levelled off at around 56% by day 8. CB showed a steady slow rate of germination compared to fully ripe which levelled off around 10% by day 10.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Effect of slimy seed coat removal and seed maturity on the germination of horned melon seed.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResults showed no interaction between stages of seed harvesting and slimy seedcoat removal (P = 0.331). Seed harvesting stages did not result in significant differences in the germination of horned melon seed. However, significant improvement in seed germination occurred when the slimy seedcoat was removed (P = 0.001). Seed with intact slimy seedcoat had a germination percentage of 59.2%, which was 27.5% lower than seed with seed coat removed, with 86.7% germination (\u003cem\u003eTable 3).\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eTable 3\u003c/em\u003e. Effect of slimy seedcoat removal and stage of seed harvesting on germination percentage of horned melon seed in the laboratory experiment (Source: Authors\u0026rsquo; development based on the analysis of samples).\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/69519_bce2c0439cd956a6/69519_custom_files/img175067412331.png\"\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eIn the pot experiment, there was no interaction between stages of seed maturity at harvest and slimy seedcoat removal on seed germination (P = 0.284). The seed harvesting stage did not result in significant differences in the germination of horned melon seed. The removal of the slimy seedcoat led to an improvement in seed germination (P = 0.010) (\u003cem\u003eTable 4\u003c/em\u003e).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eTable 4\u003c/em\u003e. Effect of gel removal and stage of seed harvesting on germination percentage of horned melon seed in the pot experiment (Source: Authors\u0026rsquo; development based on the analysis of samples)\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/69519_bce2c0439cd956a6/69519_custom_files/img1750674123.png\"\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eNew and emerging crops are essential in ensuring food security and meeting future food demands (Poltenen-Sainio et al. 2011; Okigbo and Ugwu 2021). Their introduction to mainstream cultivation should, be preceded by comprehensive studies on breeding, agronomy, and crop protection. A reliable seed system needs to be developed for these to supply growers with reliable seeds (Hampton et al. 2013; Adelabu and Franke 2023). The current studies looked at the morpho-physiological characteristics of horned melon seed harvested at three different fruit maturity stages. The study demonstrated that the total soluble solid composition of horned melon pulp increased from the mature green fruit to the fully ripe fruit. \u0026nbsp;The increase in sugar content from the mature green to the break colour was in the order of 47% while the increase from the broken colour to the fully mature was 106%. The fully ripe fruit contained 153% more soluble solids compared to the mature green (MG) fruit. Seed weight (1000 seed weight) increased with the\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003estage of ripening, with the least weight observed in mature green fruit. Seed weight in cucumber (\u003cem\u003eCucumis\u003c/em\u003e \u003cem\u003esativus\u003c/em\u003e L.) increases with late fruit harvest as well as fruit storage duration after harvest (Pathania et al. 2022). This phenomenon could be true of the horned melon fruit, as results indicate a marked increase in seed weight, consequent with ripening. These results suggest that seed filling and embryo development in melons starts immediately before the break stage, progressing through to the fully matured fruit and possibly in storage.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe quality of seed is a key component of crop production (Gupta et al. 2021). It determines the germination percentage, vigour and eventual crop stand. Thus, optimising seed harvesting is key to the production of good-quality seeds (Passam et al. 2010). In our study, the highest number of germinated seeds in the lot was extracted from fully mature fruit, followed by seed extracted from fruit harvested at colour break stage. Seed extracted from the mature green fruit showed no signs of germination after 12 days of monitoring. While for most salad lovers, the eating quality could be best at the mature green stage, the seed at this stage is immature, and will not germinate. Overall, the germination percentage for all maturity stages was found to be generally low when compared with seed industry requirements, which set the minimum germination percentage closer to 100% for a seed lot (Hampton et al. 2013). We, therefore, presumed that another factor could be at play in reducing overall germination percentage even for the stages that germinated. Further experiments were thus carried out to ascertain if the presence of the slimy seedcoat around the seed could have prevented many of the seeds from germinating.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn the second and third experiments, the influence of slimy seedcoat on horned melon seed germination was assessed in laboratory and greenhouse pot experiments. Removing the seed coating resulted in a significant improvement in seed germination. Seeds whose slimy seedcoat was removed showed higher germination on 6\u003csup\u003eth\u003c/sup\u003e day when compared with seeds with the slimy seedcoat intact. Germination progressed to peak on 9\u003csup\u003eth\u003c/sup\u003e day with seed extracted from mature yellow fruit peaking at 91% for the coatless seed and 75% germination for the seed with slimy seedcoat intact. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFurther, the two experiments revealed that germination increased from 59% in the laboratory experiment to 75% in the soil. It was also noted that the speed of germination was faster in the soil than in the petri dishes. Seed lot germination is dependent on the age of the seed, seed pre-treatment, and germination conditions (Thompson et al. 1993). The study showed that, the gel surrounding the horned melon seed provide a second barrier to germination which needs to be broken, for optimum germination to occur. This could be an adaptation measure by the horned melon seed to prevent germination in the wild, when no sufficient rains have been received. The coat stays wrapping the seed and will need soil microbial processes to be broken down. However, the increase in germination in the soil is comparatively small for commercial production.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe current study aimed to understand horned melon seed maturation for seed harvesting. The study established that the stage of fruit harvesting influenced the germination capability of the seed. The mature green fruit, which is often eaten as salad was shown to produce a seed that is light (measured by 1000 seed weight), was immature and did not germinate. Fruit harvested at the break colour produces a seed that has comparatively better seed weight with improved germination. The best germination was observed in seeds harvested from fully ripe fruit. The study further revealed that; germination is impeded by the presence of a slimy seedcoat surrounding the seed. The seed of a horned melon is enclosed in a slimy seedcoat which prevents early seed germination. Thus, the study recommends seed harvesting from fruit that has matured at least to the colour break stage, and the removal of slimy seedcoat covering during seed processing to ensure optimum germination. To the best of our knowledge, this is one of the few studies (especially in Africa) that reveal the significant effects, benefits, and influence of horned melon and how they could be critical for food security and nutrition.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThe research was partly funded by the Innovation Fund of the Midlands State University Research Board.\u003c/p\u003e\u003ch2\u003eAuthor contributions\u003c/h2\u003e \u003cp\u003e \u003cb\u003eTavagwisa Muziri\u003c/b\u003e: Conceptualisation, Methodology, Supervision, Software \u003cb\u003eNelson Mlambo\u003c/b\u003e: Investigation, Writing \u0026ndash; original draft preparation \u003cb\u003eChifamba Marveline\u003c/b\u003e: Validation, Software- validation, \u003cb\u003eThembilihle Mhlahlayazi\u003c/b\u003e: Laboratory - validation, \u003cb\u003eBridget Mwabvu\u003c/b\u003e: Writing \u0026ndash; reviewing and editing, Investigation -validation, visualisation \u003cb\u003eIgnatious Chagonda\u003c/b\u003e: Investigation, Writing \u0026ndash; reviewing and editing, \u003cb\u003eTendayi Madanzi\u003c/b\u003e: Writing \u0026ndash; reviewing and editing, \u003cb\u003eMarjory RuvimboTakawira\u003c/b\u003e: Investigation- laboratory techniques. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eThis study benefited from studies done by the following students: Nelson Mlambo, Thembilihle Mhlahlayazi and Marvelline Chifamba, for the partial fulfilment of their BSc Horticulture Degrees. Equipment and facilities to carry out this research were availed by the departments of Horticulture and Agronomy as well as the Department of Agriculture Practice of the Midlands State University. The authors are sincerely grateful for this support.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAdelabu, D. B. \u0026amp; Franke, A. C. Status of underutilized crop production: Its potential for mitigating foof insecurity. \u003cem\u003eAgron. J.\u003c/em\u003e \u003cb\u003e115\u003c/b\u003e, 2174\u0026ndash;2193 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmagon, K. I., Wannang, N. N., Ior, L. \u0026amp; Chris-Otubor, B. O. Flavonids extracted from fruit pulp of Cucumis metuliferus have antiviral properties. \u003cem\u003eJ. Pharm. Res. Int.\u003c/em\u003e \u003cb\u003e2\u003c/b\u003e (4), 249\u0026ndash;258 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChacha, J. S. et al. Chapter 7 \u0026ndash; Underutilised fruits: Challenges and constraints for domestication, Editor(s): Rajeev Bhat, Future Foods. Academic Press. 133\u0026ndash;150. ISBN 9780323910019. (2022). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.20546/ijcmas.2021.1001.245\u003c/span\u003e\u003cspan address=\"10.20546/ijcmas.2021.1001.245\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGupta, N. et al. Challenges and opportunities in cucumber seed production. \u003cem\u003eInt. J. Cur Microbiol. Appl.\u003c/em\u003e \u003cb\u003e10\u003c/b\u003e (01), 2135\u0026ndash;2144. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.20546/ijcmas.2021.1001.245\u003c/span\u003e\u003cspan address=\"10.20546/ijcmas.2021.1001.245\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHampton, J. G., Boelt, B., Rolston, M. P. \u0026amp; Chstain, T. G. Effects of elevated CO2 and temperature on seed quality. \u003cem\u003eJ. Agric. Sci.\u003c/em\u003e \u003cb\u003e151\u003c/b\u003e, 154\u0026ndash;162. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1017/S0021859612000263\u003c/span\u003e\u003cspan address=\"10.1017/S0021859612000263\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKunene, E. N., Nxumalo, K. A., Ngwenya, M. P. \u0026amp; Masarirambi, M. T. Domesticating and commercialization of indigenous fruit and nut tree crops for food security and income generation in the Kingdom of Eswatini. \u003cem\u003eCurr. Appl. Sci. Technol.\u003c/em\u003e \u003cb\u003e39\u003c/b\u003e (16), 37\u0026ndash;52 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMendlinger, S., Benzioni, A., Hyskens, S. \u0026amp; Ventura, M. Fruit development and postharvest physiology of Cucumis metuliferus Mey: a new crop plant. \u003cem\u003eJ. Hortic. Sci.\u003c/em\u003e \u003cb\u003e67\u003c/b\u003e (4), 489\u0026ndash;493 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNkosi, N. N., Mostert, T. H. C. V., Dzikiti, S. \u0026amp; Ntuli, N. R. Prioritisation of indigenous tree species with domestication and commercialization potential in KwaZulu Natal, South Africa. \u003cem\u003eGenetic Resour. Crop Evol.\u003c/em\u003e \u003cb\u003e67\u003c/b\u003e, 1567\u0026ndash;1575 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNyamapfene, K. The Soils of Zimbabwe. Nehanda Publishers. Harare. Zimbabwe.pp179. (1991).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOkigbo, R. N. \u0026amp; Ugwu, C. S. Neglected crops of Africa. \u003cem\u003eInt. J. Agric. Technol.\u003c/em\u003e \u003cb\u003e17\u003c/b\u003e (6), 2197\u0026ndash;2210 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOmotayo, O. A. \u0026amp; Aremu, A. O. Underutilised Africa indigenous fruit trees and food nutrition security: Opportunities, challenges, and prospects. \u003cem\u003eFood Energy Secur.\u003c/em\u003e \u003cb\u003e9\u003c/b\u003e (3), 220. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/fes3.220\u003c/span\u003e\u003cspan address=\"10.1002/fes3.220\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePassam, H. C., Theodoropoulou, S., Karanissa, T. \u0026amp; Karapanos, I. C. Influence of harvest time and after ripening on the seed quality of eggplanty. \u003cem\u003eSci. Hortic.\u003c/em\u003e \u003cb\u003e25\u003c/b\u003e (3), 518\u0026ndash;520. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.scienta.2010.04007\u003c/span\u003e\u003cspan address=\"10.1016/j.scienta.2010.04007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePathania, K., Kaur, N., Kaur, D. \u0026amp; Singh, R. Mobilisation of fruit pulp reserves towards seeds in Cucumber (Cucumis sativas L.) fruit harvested at variable developmental stages. \u003cem\u003ePlant. Physiol. Rep.\u003c/em\u003e \u003cb\u003e27\u003c/b\u003e (2), 268\u0026ndash;274 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePelronen-Saini, P., Rajala, A. \u0026amp; Jauhiainen, L. Hidden viability risks in the use of farm-saved small grain seed. \u003cem\u003eJ. Agric. Sci.\u003c/em\u003e \u003cb\u003e149\u003c/b\u003e (6), 713\u0026ndash;724. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1017/S0021859611000335\u003c/span\u003e\u003cspan address=\"10.1017/S0021859611000335\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2001).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRani, B. et al. Incredible benefits of exotic Kiwano (Horned melon) for wellness, vigor and vitality. \u003cem\u003eIJBI\u003c/em\u003e \u003cb\u003e1\u003c/b\u003e (2), 56\u0026ndash;59. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.46505/IJBI.2019.1204\u003c/span\u003e\u003cspan address=\"10.46505/IJBI.2019.1204\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSunderland, T. et al. Food Security and Nutrition. The Role of Forests. Discussion Paper. SIFOR. Bongor, Indonesia. (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThompson, A. J. \u0026amp; EL-Kassaby, T. M. Interpretation of seed-germination parameters. \u003cem\u003eNew. For.\u003c/em\u003e \u003cb\u003e7\u003c/b\u003e, 123\u0026ndash;132 (1993).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUsman, J. G., Sodipo, O. A., Kwaghe, A. V. \u0026amp; Sandabe, U. K. Uses of Cucumis metuliferus: A review. \u003cem\u003eCancer Biol.\u003c/em\u003e \u003cb\u003e5\u003c/b\u003e (1), 25\u0026ndash;34 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUsman, J. G., Sodipo, O. A. \u0026amp; Sandape, U. K. Phytochemical screening and acute toxicity study of Cucumis metuliferus e. mev, Ex. Naudin fruit extracts in cockrels. \u003cem\u003eInt. J. Phytomed\u003c/em\u003e. \u003cb\u003e6\u003c/b\u003e (2), 243\u0026ndash;247 (2014).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"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":"Wild fruits, horned melon, kiwano, dormancy, germination percentage","lastPublishedDoi":"10.21203/rs.3.rs-6726974/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6726974/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn the past decade, there has been a significant rise in the consumption of wild collected horned melon (\u003cem\u003eCucumis metuliferus\u003c/em\u003e). Commercial production of the crop is growing, yet little information is available on its agronomy. Seed germination experiments were carried out at Midlands State University, to establish the effect of seed maturity at harvest, and the slimy seedcoat on germination of horned melon seed. Seed was manually extracted from fruit harvested at the mature green fruit (MG), colour break stage (CB) and fully ripe (FR) stage. Three replicates of fifteen seeds from each colour group were placed in petri dishes lined with cotton wool, wetted with distilled water and placed in an incubator at 25 \u0026ordm;C. The petri dishes were arranged in a completely randomised design. Seeds from the fully ripe stage had the highest germination percentage (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05), with germination occurring in the shortest period. This was followed by the colour break (CB) stage. No germination was observed on seed harvested from mature green fruit. In the second experiment, seed harvested from the CB and FR stages were used, with one set of the seed having the slimy seedcoat removed and the second set having the slimy seedcoat intact. Germination was evaluated under laboratory incubation and greenhouse experiments. Removal of the slimy seedcoat improved seed germination in both the laboratory (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and greenhouse pot (P\u0026thinsp;=\u0026thinsp;0.021) experiments. Significant germination improvement occurred when slimy seedcoat was removed.\u003c/p\u003e","manuscriptTitle":"Different fruit maturity stages and slimy seedcoat affects seed character and germination of horned melon (Cucumis metuliferus E. Mey. Ex. Schrad)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-23 10:25:37","doi":"10.21203/rs.3.rs-6726974/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-18T05:45:17+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-17T16:49:26+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-10T13:44:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"17007074739808040148972255777836170775","date":"2025-08-28T08:31:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"134519898600997011552860131261436558251","date":"2025-08-27T12:02:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"241387758639680480382886389235042392416","date":"2025-07-02T12:12:33+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-19T08:37:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"141194351639628084778367105985257157596","date":"2025-06-19T07:48:16+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-19T03:20:40+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-05-30T03:35:51+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-27T16:53:18+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-26T01:23:14+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-05-22T17:05:55+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":"e69d9882-ee94-4ef2-b921-3e4a6790f0f9","owner":[],"postedDate":"June 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":50372934,"name":"Biological sciences/Ecology"},{"id":50372935,"name":"Biological sciences/Plant sciences"}],"tags":[],"updatedAt":"2026-03-02T16:05:46+00:00","versionOfRecord":{"articleIdentity":"rs-6726974","link":"https://doi.org/10.1038/s41598-026-40932-6","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2026-02-28 15:59:01","publishedOnDateReadable":"February 28th, 2026"},"versionCreatedAt":"2025-06-23 10:25:37","video":"","vorDoi":"10.1038/s41598-026-40932-6","vorDoiUrl":"https://doi.org/10.1038/s41598-026-40932-6","workflowStages":[]},"version":"v1","identity":"rs-6726974","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6726974","identity":"rs-6726974","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}