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Citron watermelon characterisation and trait analysis in Kalahari sands

Tembo Lenon — Wed, 01 Jan 2025 00:00:00 GMT

Title: Citron watermelon characterisation and trait analysis in Kalahari sands Authors: Tembo Lenon; Maphosa Mcebisi Abstract: Background: Citron watermelon, a drought-tolerant and nutrient-dense crop requiring low input, holds potential for enhancing food security under climate change conditions. However, it remains under-researched, with low productivity levels. Aim: To agro-morphologically characterise citron watermelon accessions and identify trait relationships relevant for variety development. Setting: The experiment was carried out at a Lupane State University Farm with Kalahari sands in Zimbabwe. Methods: A randomised complete block design field experiment, with three replications, was conducted over two consecutive seasons. Results: The accessions displayed wide diversity in fruit shape, skin colour and seed colour. Fruit yield ranged from 18.5 t/ha to 190.2 t/ha, exhibiting a strong positive correlation with the number of fruits per plant (R = 0.99) and individual fruit weight (R = 0.98). Path analysis confirmed that these traits exerted the highest direct effects on yield. Principal component analysis revealed that the first three components explained 89.85% of the total variation between accessions. Conclusion: The significant variation and trait correlations observed offer opportunities for effective parental selection and early genetic gains in breeding programmes. There is scope to improve yield-determining traits, such as the number of fruits per plant and individual fruit weight, forming a strong basis for initiating a breeding programme for this crop.

Morphological responses of sorghum seedlings to drought, heat, and combined stresses

Ndlovu Elton — Wed, 01 Jan 2025 00:00:00 GMT

Title: Morphological responses of sorghum seedlings to drought, heat, and combined stresses Authors: Ndlovu Elton; Maphosa Mcebisi; Johannes van Staden Abstract: Drought and heat stress are a global concern affecting crop productivity. The current study investigated the daily shoot and root length growth of 48 elite African sorghum genotypes and two commonly grown check varieties in response to heat and drought stresses applied individually and in combination at the early (7-day-old) and late (21-day-old) seedling stages. Genotype, stress, and their interaction significantly affected root and shoot length at both stages. Our findings indicated that the combined stresses suppressed daily shoot length growth at both stages. Drought, heat, and combined stresses equally suppressed daily root length growth during the early seedling growth stage, and drought applied separately showed the highest negative effect on root length at the late seedling stage. In general, the stress treatments showed the utmost negative effects in daily shoot and root length growth at early seedling stage than the late stage. Heat stress induced the highest relative growth reduction of 78% in hypocotyl length followed by combined stresses at 77.6% and 70.8% for drought stress. The average hypocotyl length changes ranged between 0.37 and 2.31 mm per day at early seedling stage. Root length daily growth was reduced by 69.1% under combined stress, 67.6% under heat stress, and 63.3% under drought stress at early seedling stage. Root length changes ranged between 0.35 and 2.96 mm per day at early seedling stage. At late seedling stage, the highest relative daily growth reduction was observed in shoot length (36.6%) under combined stresses while drought stress induced the highest relative daily root length reduction of 10.8%. The average shoot length changes ranged between 5.1 and 8.1 mm per day at late seedling stage while root length changes ranged between 2.7 and 3.5 mm. In reference to the independent genotypic effects, genotype IS13904 displayed the highest performance in hypocotyl and root length growth at the early seedling stage. At the late seedling stage, genotypes IS6994 and NPGRC1478 showed tolerance to at least two of the assessed stress conditions in terms of daily root length growth. Genotypes IS30164, IS30015, and IS9567 showed similar resistance in shoot growth. The overall analysis of both shoot and root daily length growth at both seedling stages revealed the resistance of genotypes NPGRC1478 and IS30164 to drought stress applied separately and combined stressors. The identified sorghum genotypes can be used as potential donors towards tolerance to combined stresses at both seedling stages and are recommended for utilization in hot and dry agroecologies of sub-Saharan Africa due to their potential vigour in early establishment.

Diversity Of Physical Grain Quality Traits In Tropical Sorghum Genotypes

Maphosa Lindani — Sun, 01 Sep 2024 00:00:00 GMT

Title: Diversity Of Physical Grain Quality Traits In Tropical Sorghum Genotypes Authors: Maphosa Lindani; Maphosa Mcebisi; Ndlovu Elton Abstract: The current study envisioned to assess the physical traits of sorghum grain for selected sorghum genotypes. Seed for the genotypes was sourced from the Lupane State University Gene Bank and grown during the 2022/23 agricultural season at Lupane State University Farm experimental plots. At maturity, laboratory tests on kernel/grain hardness, 100 kernel weight, bulk density, kernel diameter, colour and determination of presence of tannins through qualitative tests were done for all the 24 sorghum genotypes. Results from analysis of variance demonstrated highly significant differences (P<0.001) on kernel weight, kernel diameter, kernel hardness and grain hardness showing a great diversity of physical traits among all the 22 genotypes and 2 commercial varieties of sorghum. Mean 100 kernel weight was 2.59g, kernel diameter was 3.49mm, bulk density was 1.23g/cm3 and kernel hardness was 28.9%. Visual assessment was done on grain colour and seed was classified under red, cream, white and brown sorghums, and mixed colours. A chi-square test found a significant relationship between grain colour and presence of tannins. Genotypes NPGRC3124, IS9405 showed moderate levels of tannins while IS13996, IS29925, NPGRC1699, NPGRC1156 and NPGRC1478 had high levels. A highly significant strong positive correlation was shown for sorghum genotype between kernel diameter and kernel weight (r=0.81 at p≤0.05). Highly significant positive correlation was also observed between bulk density and kernel weight (r=0.4173 at p≤0.001). Kernel hardness has a strong positive correlation with bulk density (r=0.6242). Quantification of tannins is recommended to prevent negative effects on human and livestock health.

Genetic analysis of yield related traits in landrace × commercial watermelon hybrids

T. Nyurura — Sat, 01 Jan 2022 00:00:00 GMT

Title: Genetic analysis of yield related traits in landrace × commercial watermelon hybrids Authors: T. Nyurura; Maphosa Mcebisi Abstract: Watermelon [Citrullus lanatus var lanatus L.] is a major xerophytic crop originating in Africa especially grown in subtropical and tropical parts of the world. However, few adapted varieties are available to promote greater yield and make watermelon a viable commercial crop of choice. Path analysis and combining ability was carried out for yield related traits among three popular local landraces; Landrace1, Landrace 2 and Landrace 3 collected in Zimbabwe and three commercial watermelon varieties ‘Congo’, ‘Charleston Grey’ and ‘Crimson Sweet’ in plots arranged in an RCBD replicated 3 times. A complete diallel mating design was used to generate 36 F1 genotypes which together with the parents were evaluated for several quantitate traits. Data on correlations, path analysis, GCA and SCA between fruit yield and other traits were computed using Microsoft Excel and GenStat 17. Individual fruit weight (FIW) and the number of fruits per plant (NF) were found to be significantly linked with final fruit yield. Significant positive correlations were also observed on NF and number of female flowers (NFF), number of vines (NV), and FIW and these traits could be recommended as reliable selection indicators for creating high yielding watermelon genotypes. Path analysis showed that FIW and NF were the most important contributors to watermelon yield. GCA and SCA effects were significant and positive for yield which indicates that the traits are controlled by both additive and non-additive genes. ‘Crimson Sweet’ and ‘Landrace 1’ were the best pollen sources whereas ‘Landrace 1’ and ‘Landrace 2’ were the highest yielders when used as female parents. Overall, results from this study identified usable yield related proxies and need to incorporate local landraces germplasm in watermelon improvement.