Path Analysis and Heritability Estimates of Yield and Yield Components in Vegetable Cowpea as Influenced by Planting Season

摘要

The knowledge of the relationship that exists between yield and its components in vegetable cowpea is necessary for selection of cultivars that will improve productivity. The study was undertaken to understand the direct and indirect effects of yieldrelated traits in vegetable cowpea to pod yield. Seven vegetable cowpea genotypes used for the study were obtained from the International Institute of Tropical Agriculture, 11TA. Ibadan and Nsukka in Enugu State, Nigeria. Data collected on the yield andrelated traits were subjected to analysis of variance in which the season was regarded as a random effect and genotypes as fixed. Correlation coefficients and Path analysis of the traits as well as heritability estimates were conducted. Results showed that twelve out of the fifteen crop attributes measured were significantly different amongst the genotypes. Genotypic coefficient of variation was lower than the phenotypic coefficient of variation for all the traits. Number of seeds/pod, pod length, leafarea and plant height had broad sense heritability estimates greater than 90%. Number of pods/plant showed higher positive direct effect as well as correlation on pod yield than other yield traits (0.972 and 0.936, respectively). Number of pods/m2 and seeds/plant showed negative direct effects o n pod yield (-0.197, -0.01, respectively) even though they had significant positive correlation to pod yield. The indirect effects of the two traits through number of pods/plant were positive (0.46, 0.31, respectively) and high and seemed to be the cause of the significant correlation between the traits and pod yield. In conclusion, selecting vegetable cowpea genotypes high in number of pods/plant that showed high magnitude of positive direct effect on pod yield would sustain high yields. This is most likely as the trait is highly heritable and compliments others.