Evaluation of Drought Tolerance in Emmer Based Wheat Double Haploid Lines Using Surrogate Traits and Stress Tolerance Indices

Wheat is one of the major cereals and staple food cultivated worldwide, affected by severe environmental and climate changes. Global warming has led to significant variations in wheat production, accounting for losses up to 6.4% for each 1°C rise in temperature. Recurrent droughts in cultivable areas are anticipated to increase the risk of wheat yield loss by almost 12% by the end of the 21stcentury. The present study was undertaken to identify component traits contributing to drought tolerance and to evaluate wheat doubled haploid (DH) lines for drought tolerance using various stress tolerance indices. Fifty-three wheat DH lines and 11 check varieties were evaluated for grain yield, agronomic, physiological traits and drought tolerance indices under rainfed and restricted irrigation conditions in the 2019-20 cropping season. The results of ANOVA revealed that various yield contributing, agronomic and physiological traits showed highly significant genotypic variation. A significant positive correlation was observed between grain yield under rainfed (Ys) and restricted irrigation (Yp) conditions and geometric mean productivity (GMP), mean productivity (MP), harmonic mean (HM), stress tolerance index (STI) and yield index (YI). Principal component analysis (PCA) showed a significant positive correlation between stress susceptibility index (SSI) and tolerance (TOL). Based on PCA and cluster analysis, the test entries like DH 989 and DH 554, along with check cultivars NI 5439, NIAW 1415, DPW 621-50, were more stable in a rainfed environment while DH 807, DH 430, DH 435, DH 417 and DH 431 were highly adapted to restricted irrigation conditions.DH 66, DH 227,DH 931, DH 62, DH 942 DH 875, DH 134 and DH 179 were identified as susceptible genotypes. Cluster analysis also classified the genotypes into four groups, i.e., resistant, susceptible, tolerant and moderately tolerant to drought conditions. As per our study, few genotypes susceptible to drought exhibited yield reduction while the tolerant genotypes were stable, suggesting their genetic variability and utilization in a breeding program.