Evaluation of the effect of deficit irrigation regimes on grain yield and yield components of safflower genotypes

In order to evaluate the effect of water deficit stress on seed yield and yield components of safflower genotypes (Carthamus tinctorius L.), an experiment was conducted as a split plot with three replicates at the research filed of University of Shahrekord in spring 2016. Treatments consisted of three levels of irrigation based on 100%, 75% and 50% of the plant’s water requirement and three selected safflower genotypes including Sina, Isfahan and Faraman. Results indicated that deficit irrigation caused a significant reduction in all traits including the number of lateral branches per plant, plant height, head number per plant, number of seed per head, seed thousand weight, seed yield, oil percentage, oil yield, biological yield and harvest index. The lowest values of seed yield (1196 kg.ha-1) and oil yield (313 kg.ha-1) were obtained in the deficit irrigation treatment of 50 %plant water requirement and the highest seed yield (2310 kg.ha-1) and oil yield (561kg.ha-1) were obtained in 100% plant water requirement. The results showed that there was a significant difference among investigated safflower genotypes, and the highest seed yield (1998kg.ha-1) and oil yield (561kg.ha-1) were obtained in Sina genotype and the lowest seed yield (1659kg.ha-1) and oil yield (426 kg.ha-1) were obtained in local Isfahan genotype. The results showed that the differences among genotypes in terms of morphological traits, oil percentage, and oil yield were important components that could be used to select genotypes or appropriate cultivars with drought conditions.