Performance evaluation of novel safflower (Carthamus tinctorius L.) genotypes under salinity stress conditions

Salinity stress is a widespread environmental challenge impacting global crop production. To develop salt-tolerant safflower (Carthamus tinctorius L.) cultivars and lines, a factorial experiment was conducted using a randomized complete block design with three replications in Darab Fars during the 2021-2023 crop year. The first factor encompassed seven safflower lines and a novel variety, with Padideh as a control. The second factor involved two levels of irrigation water salinity (0.98 and 7.8 dS m-1). The study assessed multiple traits, including grain yield, biological yield, pod count per plant, seeds per pod, 1000-seed weight, sub-branch count, plant height, harvest index, crude oil percentage, and mineral concentrations (sodium, potassium, chlorine) as well as the potassium-to-sodium ratio. Significant effects of cultivar and irrigation water salinity were observed for all traits (p<0.01). Irrigation with saline water significantly reduced yield and its components, except for the number of branches. Saline irrigation increased sodium, potassium, and chlorine concentrations while decreasing the potassium-to-sodium ratio, crude oil percentage, and oil yield. Among the safflower genotypes, Padideh and Mec248 exhibited the lowest and highest yields under saline conditions, respectively. Mec248 demonstrated superior performance under both saline and non-saline conditions, making it the standout line in the study. Parnyan, with moderate yield, showed greater salinity tolerance, as indicated by minimal differences in seed and oil yields under saline and non-saline conditions (10.9% and 14.02%, respectively) and a high potassium-to-sodium ratio in its leaves.