Generation means analysis in cowpea for flower bud thrips in Mali

Abstract

Transfer of resistance gene in cowpea is under several factors making it difficult. As for cowpea flower bud thrips, two sets of crosses were done from two resistant (TVu 1509 and Sanzisabinli) and one susceptible (M’barawa) parents. The aim of this study was to determine the mode of gene action involve in flowers bud thrips (Megalurothrips sjostedti) resistance control into cowpea. Six generations (P1, P2, F1, F2, BC1P1 and BC1P2) were evaluated using Randomized Complete Block Design under natural infestation at three locations. Data were recorded with parameters such as number of adult thrips, total number of pods per plant and damage scoring. Results revealed the involvement of fixing and non-fixing gene effects into thrips resistance control with additive (n), dominance (h) and additive x dominance (j) as the modes of gene action predominantly controlling flower bud thrips resistance in cowpea. High to moderate broad sense and narrow sense heritability were recorded with most of the traits while low narrow sense of heritability (0.22) was scored with parameter number of peduncles per plant. Polygenic resistance was involved to control thrips resistance among segregating and nonsegregating populations that suggest ways to enhance cowpea landrace resistance to flower bud thrips attacks through classical breeding.