Estimating the inheritance of drought-tolerance and yield-associated traits of groundnut (arachis hypogaea l.) Using generation mean and variance analysis of parental, f1 and the segregating populations (backcrosses and f2)

Abstract

Groundnut (Arachis hypogaea L.) is a vital legume crop globally, particularly in semi-arid regions where drought stress significantly hampers yield and productivity. The inheritance of drought tolerance and yield-associated traits remains a key challenge in groundnut breeding programs. This study aims to estimate the genetic basis of drought tolerance and yield-associated traits using generation mean and variance analysis of parental, F1, and segregating populations (F2 and backcrosses). The study was conducted at the Department of Ecological Agriculture, School of Agriculture, Bolgatanga Technical University, Ghana. Hybridization activities were carried out in a screen house starting on August 2, 2022, to develop bi-parental crosses. Field evaluations of parental lines (P1 and P2), F1, F2, and backcross generations (BC1.1 and BC1.2) were conducted between January and November 2023 under two water regimes: well-watered (WW) and water-stressed (WS) conditions. The experimental design was a randomized complete block design (RCBD) with four replications. The genetic material included the drought-tolerant landrace Chinese (M) and three other landraces, Sinkara (M), Ndogba (F), and Chaco-pag (F), selected for their high pod, seed, and biomass yields, as well as their farmer-preferred traits. Analysis of variance revealed significant differences among generations for traits such as days to flowering, plant height, pod weight, seed weight, and biomass yield. Estimates of narrow-sense heritability (h2n) ranged from 0.07 (harvest index) to 0.96 (dry biomass), while broad-sense heritability (H2b) values were consistently high (>0.65), indicating strong genetic influence on these traits. Generation mean analysis suggested the predominance of additive gene action for most traits, though dominance and epistatic interactions were also significant for specific traits.