QUANTITATIVE TRAIT LOCI FOR YIELD AND YIELD-ASSOCIATED TRAITS IN CHICKPEA UNDER DROUGHT STRESS

Abstract

Crop yield is a complex phenomenon, controlled by several genes, each contributing to the overall phenotypic expression; which is affected by environment and genotype x environment interactions. Identifying and mapping quantitative trait loci (QTLs), make tracing these traits during breeding possible and easy. The objective of this study was to identify QTLs associated with chickpea (Cicer arietinum L.) grain yield and its associated traits, under drought stress. The experiment was conducted using 188 F3:5 genotypes from ICCV 05107 x ICCV 94954 crosses. Genotypic data were from 49 polymorphic simple sequence repeat (SSR) markers; while phenotypic data were obtained from a field evaluation designed in a 19 x 10 alpha lattice. The study was replicated thrice on three sites, namely at Koibatek Agricultural Training Centre, Muserech; and at the Kenya Agricultural Research and Livestock Organisation, Marigat. Eight QTLs were mapped on a linkage map spanning a total length of 335.04 cM, with varying phenotypic variation expression (PVE%). These QTLs include, one each for days to maturity, 100-seed weight, and two each for above-ground biomass, harvest index, and grain yield. Five major QTLs having PVE ranging from 10.37 to 32.39%, were identified for days to maturity, 100-seed weight above-ground biomass, harvest index (HI), and grain yield. Four of the eight QTLs were mapped on linkage group 4 (LG4); days to maturity, 2 for above-ground biomass, and grain yield. The QTLs mapped are useful in genomic-assisted breeding for chickpea yield improvement. However, there is a need for marker saturation on LGs and specific genes identified for effective marker-assisted breeding.