Analysis of Drought Susceptibility Index in Indian Mustard [Brassica juncea (L.) Czern and Coss]

Abstract

Background: Climatic variations such as drought have high level of impingement on the yield of rain-fed crops like mustard. A drought is an extended period of months or years when region notes a deficiency in its water availability. Water stress causes heavy yield losses in Indian mustard (17-94%). Low water availability during stem elongation, flowering and pod development causes reduction of pods per plant leading to reduction in grain yield. Very meagre efforts have been made towards improving drought tolerance of this crop. Hence there is an urgent need for, development of water use efficient genotypes. Drought Susceptibility Index (DSI) is a measure of drought, based on loss of yield under drought conditions in comparison to the yield under normal conditions. It expresses the separate effects of yield potential and drought susceptibility on yields under drought. In these terms, lower DSI is considered synonymous with higher drought tolerance. In view of above facts, present study is aimed at investigating the effects of drought on yield attributing traits with, the objective of identifying Indian mustard genotypes and their hybrids which can withstand water stress with minimum loss in yield. Methods: Nine Indian mustard genotypes and their F1s were evaluated under irrigated and rainfed conditions to study the effect of drought by calculating DSI, on yield and yield traits and to characterize their relative tolerance against drought at the Agriculture Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during Rabi 2017-18 season. Observations were made for different yield and yield related traits. Result: Genotype RB-50 was found as tolerant for seed yield per plant with DSI 0.38 while hybrids RB-50×RH-749 and RB-50×Giriraj were exhibiting tolerant DSI values for siliqua per plant, 1000 seed weight, seed yield per plant and oil content. These parents and F1s would serve as useful donors and hybrids respectively, in mustard breeding programmes for improving drought tolerance.