Evaluation of physiological traits for improving water deficit tolerance in spring safflower

Drought stress is one of the major limitations to plant productivity across the
world. Identifying appropriate selection tools can facilitate the breeding of plants for drought
tolerance. In the present study, relative water content (RWC), excised leaf water retention
(ELWR), leaf water content (LWC), relative water lose (RWL), moisture retention capacity
(MRC), leaf chlorophyll content and leaf proline content were used as physiological
parameters for the study of 20 spring safflower genotypes under drought-stressed and
normal conditions in the research field of Islamic Azad University, Khorasgan Branch, in
2012. The experiment was a split-plot on the basis of a randomized complete block design
with three replications. It was found that drought stress significantly decreased relative
water content and leaf water content. These traits were accompanied with a great loss of
yield in sensitive genotypes. The highest amounts of chlorophyll content, proline
accumulation, ELWR and RWC were observed in Afghanistan and Kuwait, Shiraz,
Afghanistan, Paraguay andMarand genotypes, respectively. On the other hand, the lowest
amount of proline accumulation, ELWR and RWC were obtained in genotypes Paraguay,
Saffire and Afghanistan, respectively. It seems that Afghanistan genotype was more capable
of being cultivated in regions experiencing water deficiency. Overall, proline accumulation
(along with the accumulation of glucose and potassium), higher chlorophyll content and
relative water content can be used as selection criteria in drought stress conditions.