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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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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