Breeding and release of high yielding and drought tolerant varieties along with advance agronomic practices are effective ways to manage drought and water deficit in agriculture. This experiment was conducted in order to identify tolerant genotypes to drought and evaluation of main characters and drought resistance indices on 20 bread wheat genotypes (18 promising lines and 2 checks, Sardari and Azar-2) during three cropping seasons (2002-2005) in two locations, Kermanshah province, Sararood station (moderate cold area) and Maragheh, Maragheh station (cold area). The genotypes were evaluated in a RCBD design fashion with four replications. Simple and combined analyses of variance for three years were carried out. The results showed significant differences among genotypes in different irrigation application. The highest grain yield, yield stability, and drought tolerance were belonged to the genotypes nos.1 (14 Gene Bank Material), 2 (914 Gene Bank Material), 4(F9.10/May"s"//Sabalan), 19 (Sardari), 20 (Azar-2), 3 (Turkey 13//F9.10/Maya"s") and 14 (Fengkang15/Sefid), under different irrigation scheme. Evaluation of stress tolerance indices i.e. stress tolerance index (STI), geometric mean productivity (GMP) and Mean productivity (MP) also showed the superiority of the above mentioned genotypes. Evaluation of different stress tolerance indices indicated that STI is a general index which can be used as selection criteria in breeding programs.
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