Physiological trait diversity for drought tolerance in Indian mustard (Brassica juncea) and genotypes mapping

Abstract

A set of 18 genotypes of Brassica juncea L. including four released cultivars (checks) were screened for various physiological traits under normal and deficit moisture in cemented blocks with three replications. Maximum SCMR(SPAD chlorophyll reading) with minimum per cent reduction under moisture stress was recorded in DRMRCI 72, 80 and 89 genotypes at 45 and 60 DAS compared to check cultivars. Higher moisture stress index (MSI), relativewater content (RWC), lesser excised leaf water loss and transpiration rate were observed in DRMRCI 80, DRMRCI 89 and DRMRCI 90 genotypes under moisture stress condition. The DRMRCI 66, 72 and 89 genotypes recordedhigher siliquae wall weight, siliquae number on main shoot, seed yield and YSI (yield stability index) under moisture stress compared to check cultivars. Under stress condition, seed yield showed significant and positive correlationwith YSI (r=0.68), number ofsiliquae on main shoot (r=0.72) andRWC (r=0.46). Similarly, YSI showed significant and positive correlation with SCMR (r=0.49 at 45 and r=0.61 at 60 DAS), MSI (r=0.60), RWC (0.78), siliquae wall weight (r=0.77) and number of siliquae on main shoot (r=0.58). Based on SCMR, MSI, RWC, siliqua wall weight and number, genotypes DRMRCI 72, 80, 89 and 90 were identified as drought tolerant and may be used for breeding of drought tolerant varieties of Indian mustard.