Study of variability of bread wheat lines based on drought resistance indices

Abstract

Current research was conducted to evaluate drought tolerance potential in wheat lines based on Augmented Design with four checks (Bahar, Cross Alborz, Sardari and DN-11 cultivars). Drought tolerance and susceptibility indices for yield and its principal components were calculated in two irrigation and drought stress conditions. Result of correlation coefficients analysis revealed that there was a positive and significant correlation between yield in stress and non-stress environments (0.403). Indices GMP, HAM, MP, YI and YSI showed higher correlation with Ys and were known as suitable indices for survey of drought resistance and achieve high yield in both environments. The triplot diagram based on STI showed that genotypes No. 11, 34, 22, 13, 24, 25, 16, 17, 15 and 8 had high yield and situate in the region according to Fernandez's model that were high yield in the stress and nonstress conditions. The first two components explained about 99.53% of the total variations. In this study, 61.70% of total variability determined by the first component that had high and positive correlation with GMP, MP, DRI, HAM, STI, YSI, YI and yield in both stress and non-stress conditions. So the first component can be nominated as yield potential and drought tolerance component. Second component determined 37.82% of total variability and showed negative correlation with YI, YSI, DRI and Ys and positive correlation with SSI, TOL, MP, GMP, STI, HAM and Yp. This component can be nominated as stress susceptibility component. Relationship between indices showed the indices GMP and STI are high correlated with Yp. Based on biplot analysis, genotypes that are located in the midsection and near the center showed almost same yield in both conditions. The MP, YI, DRI and YSI Indices were highly correlated with Ys. Then based on these indicators genotypes can be selected via high yield in stress conditions. The SSI and TOL Indices showed high correlation with other indices. So genotypes that are near these indices seem to be susceptible to stress conditions.