Evaluation of Water Deficient Stress Tolerance in some Wheat Cultivars and Their Hybrids using Canonical Discriminant Analysis and Genotype by Trait Biplot

Canonical discriminant analysis (CDA) in combination with cluster analysis and genotype by trait (GT) biplot analysis methods were used to assess 9 wheat cultivars having different degrees of tolerance along with 36 F1 hybrids derived from partial diallel crosses, using stress tolerance indices, in two levels (well watered and cessation of irrigation at pollination stage). Cluster analysis classified genotypes into three clusters and the results used to CDA as classifying variable. The first canonical variable was under the influence of high canonical coefficients for STI, HM, MP, GMP, Yp and Ys. Canonical coefficients for SSI and TOL in the second canonical variable were remarkable. The first canonical variable differentiated genotypes based on yield potential and stress tolerance and the second canonical variable distinguished stress tolerant genotypes from the sensitive ones. The scatter plot of two significant canonical variables characterized three distinct groups and all pairwise Mahalanobis distances among groups were significant. The genotypes in group 1 had high yield in stress and non-stress conditions and the genotypes of group 3 had more stress tolerance and less susceptibility to stress. To identify tolerant and high yielding genotypes in both stress and non- stress conditions, GT biplot analysis based on combination of STI and SSI was used and superior genotypes which simultaneously have higher yield potential and stress tolerance were introduced.