Evaluation of grain yield and its components in three bread wheat cultivars under drought stress

1 SUMMARY An experiment was carried out between 2007- 2008 in the Dryland Agriculture Research subInstitute Sararood in order to study the effects of drought stress on yield and yield components of wheat cultivars under field conditions. The experiment was based on split plot in a randomized complete block design with three replications. The main plots included drought stress treatments at 4 levels: I 1 -drought stress at the start of stem elongation stage (31 of the Zadoks); I2-drought stress at the start of boot stage (43 of the Zadoks); I 3 -drought stress at the start of grain filling stage (70 of the Zadoks) and I 4 -full irrigation. The subplots included cultivars treatments at 3 levels: Chamran (C 1), Marvdasht(C 2 ) and Shahriar (C 3 ). Compared to the control treatment (I 4 ), treatments (I 1 ), (I 2), and (I 3) exhibited 85%, 57%, and 43% yield decrease, respectively. In response to moisture stress during different growth stages, Shahriar cv(C 3 ) was damaged more severely than Chamran cv (C 1) . Chamran cv (C 1) was one of cultivars with high yield potential in moisture stress conditions, especially in terminal season drought stress conditions