Screening of high yielding cultivars of safflower (Carthamus tinctorius L.) under drought stress conditions

Combined analysis of variance showed significant difference between stress and non-stress environments for grain number, grain yield, oil yield, biological yield, plant height and harvest index traits. Also, compound analysis explained that there were significant differences among all safflower cultivars in grain number, plant height, days to physiological ripening, grain filling period length and grain filling rate traits. Genotype x environment interaction analysis showed that there were significant differences only for traits 1000-grain weight, grain yield, oil percentage, oil yield, days to flowering, days to physiological ripening and their components in various environments and even among various years. Sterling cultivar had the highest oil percentage and oil yield under stress, whereas Arak 2811 had the highest grain yield. The least oil percentage was obtained in Gila cultivar. Cultivar S 149 had the highest harvest index (19.36%) and Gila had the lowest (11.6%). In no stress environment Arak 2811 showed the highest oil percentage, while sterling had the highest oil yield, but there was no significant difference between oil percentage of Sterling and Arak 2811, then sterling had an appropriate oil yield and oil percentage in both stress and non-stress environments. The least oil percentage and Oil yield were obtained in Nebraska 10 cultivar. On the whole, Sterling and Arak 2811 cultivars are proposed as high yielding cultivars with more toleration to drought stress in Isfahan and similar regions.