Multi-Year Characterisation of Drought Adaptation and Grain Quality in Synthetic Hexaploid Wheat Genotypes

This study was conducted to evaluate yield components, biochemical traits, and drought tolerance in 66 synthetic hexaploid wheat (SHW) genotypes and standard cultivar Karahan. The experiment was conducted over three growing seasons at the Absheron Scientific Research Base of the Institute of Genetic Resources. Genotypes were grown under irrigated and rainfed conditions using a randomised complete block design with three replications. Drought response was assessed from grain yield under irrigated and rainfed conditions using the stress tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), tolerance index (TOL), and stress susceptibility index (SSI). Genotypes combining high MP, GMP, and STI values with favourable stress-response characteristics were considered promising under water-limited conditions. Significant differences were observed among the evaluated genotypes for yield-related and biochemical traits under contrasting water regimes. Among the evaluated synthetic wheat genotypes, genotypes Sb7, Sb8, Sb9, Sb29, Sb30, andSb40 exhibited promising performance based on the combined interpretation of MP, GMP, and STI. These results suggest that these genotypes were able to maintain higher productivity under both favourable and water-limited conditions. Therefore, the combined evaluation of MP, GMP, and STI provided a more comprehensive and reliable approach for identifying promising synthetic wheat genotypes compared with the use of individual drought tolerance indices.