Response of ion contents and physiological traits to salinity and drought stress and genotype selection in safflower (Carthamus tinctorius)

Abiotic stresses, including salinity and drought, have a significant role in reducing plant yield. Physiological traits are more effective than morphological and agronomic traits in identifying and differentiating plant responses to stress conditions and can serve as more efficient indicators for screening stress-tolerant genotypes. Interspecific hybridization can be used to enhance genetic diversity, transfer adaptability, and improve tolerance to salinity and drought stress, leading to the development of new cultivars. In this study, ۱۰ genotypes, including four recombinant inbred lines (RILs) derived from interspecific crosses between C. tinctorius and C. palaestinus (coded as TP) and C. oxyacanthus (coded as TO), the parental species C. tinctorius, two commercial cultivars (Kooseh and Padideh), and three elite genotypes selected from previous studies, were evaluated under three environments: drought (۹۰% soil moisture depletion), normal (۵۰% soil moisture depletion), and salinity (EC = ۲۰ dS/m). The results revealed significant genetic diversity among the studied genotypes in terms of all traits and tolerance to salinity and drought stress. Both drought and salinity stress reduced seed yield (by ۳۴% and ۵۴%, respectively) and relative leaf water content (by ۳۲% and ۴۰%, respectively) while increasing the activity of antioxidant enzymes (ascorbate peroxidase, peroxidase, and catalase). Correlation analysis indicated a significant positive relationship between relative leaf water content and seed yield in the studied genotypes. Given the more increased enzymatic activity under salinity stress and the lesser reduction in relative leaf water content compared to drought stress, followed by a greater decline in seed yield under drought, it can be concluded that the studied genotypes exhibited higher tolerance to salinity stress than to drought stress. Tolerant genotypes for both drought and salinity conditions were identified: genotype ۶۱TP (derived from interspecific hybridization) was recognized as salinity-tolerant, genotype G۵۹ (a global selection) as drought-tolerant, while genotype G۴۷ (a global selection) and the commercial cultivar Padideh were identified as stress-sensitive. The identified genotypes can be utilized for releasing new cultivars or further crossing in future breeding programs.

کلیدواژه ها:

Ascorbate peroxidase ، Safflower ، Water deficit ، Relative water content ، آسکوربات پراکسیداز ، گلرنگ ، کم آبی ، محتوای نسبی آب برگ