Study of Some Physiological Indices, Seed Yield and Its Components of Oilseed Rape Varieties Under Drought Stress

Evaluating of some physiological indices for recognizing water deficit effects, selecting water deficit tolerant oilseed rape genotypes and also evaluation of drought effects on seed and oil yields and its components were the goals of this study. The experiment was conducted as factorial based on a randomized complete blocks design with three replications in East Azarbaijan Research Center for Agriculture during 2010-2011.The experimental factors were irrigation with three levels including: non-stressed, water deficit stress during rosette stage in fall and seed filling stage and genotype including: Karaj 1, Karaj 3, Opera, Okapi, Licord and Modena. Water deficit during rosette stage increased leaf temperature and decreased relative water content and stomatal conductance, but effects of drought on seed yield and its components were not significant. Whereas water deficit during seed filling stage, increased leaf temperature and decreased leaf relative water content, stomatal conductance, plant height, yield components except seeds per silique and finally seed and oil yields. Between seed yield with silique per plant positive correlation was seen. It seems that drought stress decreased seed yield mainly by decreasing silique per plant. leaf temperature, leaf relative water content and stomatal conductance indicated correlations with seed yield and therefore can be used for recognizing the effects of drought on oilseed rape. Okapi and Licord with 4670 and 4518 Kg/ha seed and 1861 and 1758 Kg/ha oil yield, indicated higher performances in Tabriz region respectively.