Effect of Terminal Drought Stress on Yield and Yield Components of some Oilseed rape Genotypes

The present study was conducted to investigate the terminal drought stress effect on yield and its components in oilseed rape and to identify drought tolerant genotypes with high yield potential. Thirteen oilseed rape genotypes including Karaj 1، Karaj 2، Karaj 3، Talayeh، Zarfam، Okapi، Licord، Slm046، Modena، WPN5، Opera، WPN2 and G. KH305 were evaluated under optimum and terminal drought stress conditions using a randomized complete block design with three replications at the Agricultural Research Station of Islamabad-e-Gharb in 2010-2012 cropping seasons. Combined analysis of variance showed that the effect of terminal drought stress was significant for recorded characters except oil content، the number of branches and 1000 seed weight. The mean seed yield of genotypes was decreased by 20% in response to drought stress so that seed yields in optimum and terminal drought stress conditions were 4586 kgha-1 and 3736 kgha-1، respectively. Seed yield reduction in drought stress condition was associated with reduction in seed yield components i. e. pods per plant and seed per pods. Due to favorable climatic conditions in the 2010-2011 cropping season، seed yield and it’s components were higher than those in the 2011-2012. Oilseed rape genotypes were significantly different for recorded traits except oil content. Genotype G. KH305 had the highest seed yield of 5230 and 3941 kgha-1 in optimum and drought stress conditions، respectively.