The Effects of Water Deficit on Physiological and Agronomic Responses of Six Salt Tolerant Safflower (Carthamus tinctorius L.) Genotypes

To recognize the effects of water deficit stress on physiological and agronomic responses of salt tolerant safflower genotypes, and introducing indices to selecting drought tolerant genotypes of safflower, an experiment was conducted as split plot based on a randomized complete blocks design with three replications in saline soils (6.7 dS m-1) of the East Azerbaijan Agriculture and Natural Resources Research and Education Center during 2017-18. The experimental factors included drought stress (non-stressed and stressed from flowering to maturity (and six fall safflower genotypes including: Padideh, Golemehr, Mexico14, Mexico248, Mexico295 and Parnian. Drought stress increased leaf temperature and decreased leaf relative water content (RWC), stomatal conductance and leaf chlorophyll index and also grain number per capitulum, oil percent, grain and oil yields significantly. Significant differences were seen among the genotypes in the above-mentioned indices (except for leaf temperature), yield components and seed and oil yields. Correlations among leaf temperature, RWC, stomatal conductance and leaf chlorophyll index with each other and with seed and oil yields were significant. Therefore, these indices (except for leaf temperature) can be used to select drought-tolerant fall genotypes of safflower in the region. Correlation among capitulum number per plant and grain number per capitulum with each other and seed and oil yields, were positive and significant. Hence, these yield components had important role in productivity. Golemehr, Mexico 14, Mexico 248 and Mexico 295 genotypes indicated higher seed and oil yields. It seems that the above four genotypes could be adapted to cultivate in saline areas around Urmia Lake and areas with similar climate.