Use of Physiological Parameters as Tools to Screen Drought Tolerant Safflower Genotypes

ABSTRACT: Drought stress is one of the major limitations to plant productivity across the world. Identifying suitable screening tools and also quantifiable traits would facilitate the crop improvement process for drought tolerance. In the present study, relative water content, leaf area index, stomata density and stomata length were studied as most important physiological parameters at the grain filling stage of fifteen spring safflower genotypes grown under normal and drought stress conditions in 2007 growing season. The experiment was conducted in Zanjan University, Zanjan, Iran based on randomized complete block design, arranged in split plot with three replications. The results indicated that exposure of plants to drought stress led to significant decrease in relative water content, leaf area index and stomata length and noticeable increase in stomata density. Decrease in above mentioned traits was parallel with yield loss in sensitive genotypes. The results of principal component analysis showed that the first component with more than 68% of total variation is able to separate high yield genotypes from other genotypes. According to obtained results, it seems that Dincer, Kino-74, PI-537598, PI-250537 and Gila genotypes are more suitable genotypes for drought stressed regions.