Evaluation of Drought Tolerance Indices and Their Relationship with Grain Yield of Lentil Lines in Drought-stressed and Irrigated Environments

In order to study genetic diversity of lentil lines, screening drought tolerance three indices and lines, eighteen genotypes were evaluated in a randomized complete block design with 3 replications under both stress and non-stress conditions in the Research Farm of Zabol University in 2009. Based on yields of non-stress (Yp) and stress (Ys) conditions, several quantitative drought tolerance indices, such as mean productivity, geometric mean productivity, harmonic mean, tolerance index, yield index, yield stability index, stress susceptibility index and stress tolerance index were used to evaluate the drought responses of these genotypes. GMP, HM and STI were considered as the best indices for selection of lentil lines under drought stress. Based on these indices values, TN1084 could be considered as superlative line, followed by KC210034. TN2464 was the weakest line in respect to drought tolerance. Principal component analysis revealed that the first PCA explained 66.82% of the total variation and named as the yield potential and drought tolerance dimension. The second PCA explained 32.48% of the total variability and named as a stress-tolerant dimension. Distribution of the genotypes in the PCA biplot space indicated the presence of genetic diversity among the lines for drought stress. TN1084 genotype with high PC1 was more suitable for stress and non-stress conditions. KC210034 genotype with high PC2 was more suitable for non-stress than for stress environment. Biplot based on grain yield of lines under stress and non-stress conditions revealed the results of principal component analysis and showed the possibility of diversifying the legume-predominant farming systems in Sistan. Based on cluster analysis TN1084 and KC210034 group had high yield under stress and non-stress conditions and ranked as the best group. TN2464 group had low yield positional under stress and non-stress conditions and ranked as the worst group. All in all, TN1084 and KC210034, respectively, were best line for stress and non-stress conditions and can be recommended for cultivation and parental material for breeding efforts to develop higher yielding varieties