Assessment of drought stress effects on RWC and chlorophyll content in rapeseed cultivars (Brassica napus L.)

In order to identify the suitable irrigation regime as well as determine the best canola cultivar to cultivate in dry and semi-dry regions, this study was achieved at the Agricultuaral Research Station of Islamic Azad University, Khorasgan Branch in North-East of Isfahan. This experiment was conducted as split-plot at the layout randomized complete block design with three replications during 2010-2011. The experimented factors included three levels of irrigation, viz; irrigation after 50, 100 and 150 mm evaporation from class A pan as the main plots and four canola cultivars entitled: Zarfam, Elite, SLM 046 and Okapi as sub-plots. In this experiment, total chlorophyll content, chlorophyll a, chlorophyll b and relative water content (RWC) were measured. According to the results obtained in this experiment, the most chlorophyll content were obtained by 150 mm irrigation and the most RWC were obtained by 50 mm irrigation. The cultivar effect on RWC was significant at 1% probability level so Elite and Zarafam had the most RWC. Inconclusion, Elite was recommended as the most drought tolerant in this research and the same condition.