The reaction of the autumn safflower cultivars to drought stress in Shahr-e Rey region

Drought stress is the most significant factor that confines the growth of crops such as safflower (Carthamus tinctorius L) in the arid and semiarid regions of the world. In an attempt to investigate the effect of drought stress on some of the features of the autumn safflower cultivars, a field experiment was conducted, during 2009, in the research farm of the Islamic Azad University, Shahr-e Rey branch. The research followed a split plot, randomized, complete block design and was carried out with four replications. The main plots included: two irrigation levels (irrigation throughout the growing period and the withholding of irrigation at the heading stage) and the sub plots consisted three genotypes (i.e. Goldasht, Padideh, and KW). The results indicated that the drought stress significantly reduced the grain yield and yield components. Generally speaking, it decreased the number of plant heads (11.46%), seed pods (27.65%), 1000-seed weight (14.31%), and the grain yield (45.75%). Under the control conditions, Goldasht cultivar had the highest grain yield in comparison to the other ones, but under the drought stress conditions, the difference between the cultivars was not significant.