Evaluation of Drought Tolerance in Some Wheat Genotypes using Drought Tolerance Indices

In order to determine suitable drought tolerance indices and to identify drought tolerant wheat genotypes, an experiment was conducted at the experimental field of Ardabil Agricultural Research Station in 2010-11 cropping season. Thirty wheat genotypes were evaluated in a randomized complete block design with three replications under stress as well as non-stress conditions. Drought tolerance indices including TOL, SSI, MP, GMP, STI and Harm and variance percent of traits were calculated. Results showed that traits of plant weight, peduncle length, peduncle weight, grain weight per spike, grain yield and one thousand grain weight were diminished significantly under drought stress conditions. According to correlation between drought tolerance indices and grain yield under stress and non-stress conditions, drought indices of MP, GMP, Harm and STI exhibited a high correlation with grain yield under both conditions. These indices were determined as the best indices for selecting genotypes with high yield potential under both stress or non-stress conditions (group a genotypes). Results using MP, GMP, STI and Harm indices revealed that genotypes 3, 5, 9 and 13 as tolerant and 7, 12, 16 and 28 are sensitive to drought conditions. Based on results of SSI and TOL indices genotypes 8, 9, 12, 18, 19 and 30 were tolerant and genotypes 1, 10, 15 and 25 were sensitive to drought stress conditions. Cluster analysis with Ward's method based on drought tolerance indices separated tolerant and sensitive genotypes in five different groups. Based on the results, genotypes 3, 5 and 9 were recognized as suitable for both conditions.