Using Drought Tolerance Indices in Evaluation of Some Wheat, Triticale and Tritipyrum Genotypes

To evaluate drought tolerance in bread wheat, tritipyrum and triticale genotypes, 27 different genotypes were grown as a randomized complete block design under two irrigation regimes (control and drought) in two locations (Isfahan and Shiraz) during two growing seasons (2016 and 2017). Based on grain yield, several indices including stress tolerance index (STI), tolerance index (TOL), susceptibility index (SSI), mean productivity index (MP), geometric mean productivity index (GMP), drought sensitivity index (SDI), drought index (RDI), stress susceptibility percentage index (SSPI), Harmonic mean index (HARM) and Yield stability index (YSI) were calculated. According to the results of genotypes ranking in Isfahan region, triticale lines had the highest values of MP, GMP and STI indices over two years of study. In Shiraz region, triticale lines (4115 and 4116) had the highest values for drought tolerance indices. According to SSI and TOL indices, (triticale) and wheat genotypes (Bam, Omid and Alvand) were evaluated as drought tolerant genotypes in Isfahan region and Alvand and KaCr4 genotypes in Shiraz region in two years of evaluation. According to the correlation analyses, MP, GMP, HARM and STI indices had a positive and high correlation with grain yield in both stress and non-stress environments in both Isfahan and Shiraz regions. Superior-tolerant genotypes can be used in breeding programs to increase drought tolerance in future.