This study estimated the genetic variability and gene action of several traits in the F4 and F5 rice populations to determine a trait for selection program. The trait of date to flowering and date to harvesting had narrow genetic variability, whereas trait productive tillers, number of fertile grain, and total grains had moderate to wide genetic variability. Genetic variability in trait number of fertile grain and total grains showed decreased in F5 generation compare to the F4 generation, whereas trait productive tillers, date to flowering, and date to harvesting showed an increase. Additive gene action with duplicate and complementary epistasis was found in all traits, except for trait productive tillers only showed additive gene action with duplicate epistasis. Kurtosis less than 3 was found in all traits which indicate many genes control the traits. The number of fertile grain trait showed wide genetic variability which decreased in F5 generation compare to the F4 generation, and there is an additive gene action with duplicate epistasis. It indicates selection will be effective with the trait of number of fertile grain.
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Field evaluation of 33 Bambara groundnut lines were carried out to estimate genetic variability, heritability and genetic advance. One-way analysis of variance (ANOVA) result showed significant differences for 14 of the 17 agronomic traits studied. The results on the variance components revealed that phenotypic variance had values (vigour index 2.30, pod length 10.09, seed length 1.64) that were slightly higher than the respective genotypic variance (vigour index 1.68, pod length 9.88, seed length 0.26). Similarly, the values (number of branches 41.91, number of nodes 68.72, internode length 59.02) of phenotypic coefficient of variation (PCV) were slightly higher than the corresponding genotypic coefficient of variation (GCV) (number of branches 40.11, number of nodes 66.98, internode length 57.31), suggesting a substantial genetic variability that can serve as a base for Bambara groundnut improvement. High estimates of heritability were observed for most characters like number of branches (95.70%), number of nodes (97.46%), internode length (97.10%), pod length (97.91%), and seed length (93.79%). Likewise, genetic advance values for most traits were high, pod length (201), number of nodes (200), internode length (200), number of branches (197) and seed yield (195), implying that improvement of seed yield in Bambara groundnut can be achieved through direct selection.
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Chinese jujube (
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Climate change has imposed greater challenge on cowpea production in the savannah ecology of West Africa sub-region in the recent time, however, development of varieties that combined resilience (stability) and precocity with high seed yield would be a sustainable approach to mitigate this problem. To this end, nine advanced breeding lines were evaluated along with two commercial varieties across three locations in guinea savannah ecology, using a randomized complete block design of three replications. Results obtained for seed yield and yield components indicate that the eleven cowpeas exhibited substantial variability for all plant traits studied and implications discussed. Additive Main Effect and Multiplicative Interaction (AMMI) analysis however revealed that the variations recorded were substantially attributable to genotypic component (70–80%) and less of environment (0.7–7.0%), a measure of phenotypic stability of these cowpea lines. However, seed yield and yield components vary significantly across the three locations, which further emphasize the important role of soil and climatic variables to cowpea production. In this study, two varieties (IT07K-299-6 and IT11K-61-82) consistently combined high seed yield (> 2 tons/ha) with precocity across the three locations, and could be multiplied for distribution to farmers as short-term intervention for yield increase. Reduced seed viability of these varieties reflects seed storage challenge in cowpea farming. In addition to significant contributions of some yield components to seed yield, there was evidence of strong association between precocity and high yield, and its implication for cowpea improvement discussed.
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Understanding the interrelationships between agronomic and water status characters helps development of drought tolerant cultivars. In the present study, 34 wheat genotypes were used to investigate joint variability of water status characters and yield related traits under normal irrigation regimes and drought stress in 2014–2015 growing season. The results indicated that selection of genotypes based on loadings in factors number 1, 3 and 4 would be of beneficial in terms of increasing grain yield related traits under drought stress conditions. In canonical correlation analysis (CCA), the first (U1, V1) and second (U2, V2) pairs canonical variables (CV) explained 75% and 67% of the total joint variability of agronomic and physiological traits under drought stress conditions, respectively. The first (V1) physiological CV that had positive correlation with water saturated deficit (WSD,
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An experiment was conducted to evaluate genetic variation among twenty-one fluted pumpkin genotypes for seedling traits. The seeds of the fluted pumpkin were germinated in nursery bags filled with saw dust at the Federal University of Agriculture, Abeokuta and the Federal University of Technology, Akure, Nigeria between July and August, 2013. The experiment was laid out in completely randomized design with three replications. Characters evaluated were emergence percentage (E%), emergence index, emergence index rate, vine length (cm), leaf area (cm2), number of leaves, shoot dry weight (g), and seedling vigour index (SVI). Significant (
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Poor seed yield remains a great challenge for cowpea production in sub-Sahara Africa and continuous evaluation of available genetic resource to develop high and stable yielding varieties is the panacea to this regional food security conundrum. In this study, 21 cowpea breeding lines were evaluated for phenotypic analysis of seed yield components for two years in a randomized complete block design of 3 replications. All the yield components exhibited significant genotypic variation, while flowering, pod maturity and seed yield traits recorded significant variation for years and its interactions. These cowpeas, which are predominantly early-medium maturing biotypes, exhibited relative phenotypic stability for the yield components across years (seasons) except seed yield, being a final product of complex physiological process. Relationships between flowering/pod maturity and seed size were positive and significant. By contrast, pods/plant, seeds/plant and total seed yield recorded negative correlations with pod maturity. However, seeds/plant and pods/plant are the most contributory components to seed-yield with correlation coefficients of
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Indian spinach (
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