Genetic variability, response to selection for agro-physiological traits, and traits-enhanced drought tolerance in durum wheat

Abstract

This study was undertaken to estimate the genetic variability and response to selection for twenty-four agro-physiological traits of nineteen durum wheat genotypes under drought and irrigated conditions during two cropping seasons (2017–18 and 2018–19). Large phenotypic and genotypic variations (PCV, GCV) for agronomic (3148.3, 1829.3) followed by morphological (253.3, 232.5), physiological (18.2, 17.6) and phenological (14.2, 12.6) traits were observed. The high heritability (h²) coupled with high percent of genetic advance as percent of mean (GAM%) was expressed highest in physiological traits (i.e., chlorophyll fluorescence (h² = 0.70, GMA% = 250.1) and normalized difference vegetation index (h² = 0.71, GMA% = 193.8)), followed by morphological traits (i.e., peduncle extrusion (0.90, 186.9), peduncle length (0.95, 109.2), flag-leaf length (0.85, 108.4)), agronomic traits (i.e, harvest index (0.59, 230.1), 1000-kernel weight (0.83, 42.7)) and phenological traits (i.e., days to 50% booting (0.91, 7.6) and heading (0.93, 6.9)). Based on the results, superior genotypes (URRACA, Saji and Icasyr1/3/Gcn//Stj/Mrb3) with high yielding performance, good trait profiles and high drought tolerance were identified. The findings of this research demonstrated the existence of high response to selection for agro-physiological traits in durum wheat under drought conditions, which represents potential in hybridization schemes of wisely chosen parents for creating genetically improved drought tolerant varieties.