Classification of advanced spring wheat genotypes under non-stress and drought stress conditions

In order to study grouping of advanced spring wheat genotypes under non-stress and drought stress conditions (stop irrigation in the stage of the emergence of 50% inflorescence of each experimental unit),  28 genotypes were evaluated  in 2016-2017 and 2017-2018 cropping yearin two separate experiments with a randomized complete block design with three replications in the research field of Islamic Azad University of  Tabriz. Combined analysis of variance  revealed a statistically significant difference between studied genotypes for all traits (P<0.01). Genotype × condition interaction was significant for seed yield, number of seeds in spike, plant height, harvest index in 5% probability level and 1000 seed weight and biomass in 1% probability level. The results of the present study showed that studied genotypes had different reactions in different environmental conditions for these traits. However, Genotype × condition interaction  was not significant for number of spike,  length of spike and length of  peduncle. Cluster analysis classified genotypes based on all studied traits into two groups under non-stress and drought stress conditions. Results of the discrimination function analysis confirmed this grouping. Under non-stress condition the first group includes Darya, Shiroodi, ERWYT-94-4, Roshan, ERWYT-94-7, URBWYT-94-2, URBWYT-94-4 genotypes, which mean of all traits except harvest index were higher than the total mean. Overall, results indicate that the first group was the superior group. Under drought stress condition the second group includes Darya, Shiroodi, Aftab, URBWYT-94-3, ERWYT-94-4, URBWYT-94-6, Roshan, ERWYT-94-7, URBWYT-94-7, URBWYT-94-8, URBWYT-94-9, URBWYT-94-10, URBWYT-94-2; URBWYT-94-4, which mean of all traits were higher than the total mean. The best genotypes for both cluster analysis under both non-stress and drought stress conditions, were genotypes of  Darya, Shiroudi, Roshan, URBWYT-94-2, URBWYT-94-4, ERWYT-94-4 and ERWYT-94-7.