Study of Correlation and Path Coefficient Analysis between Oil Yield and Agronomical Characters in fourtheen Cultivars of Rapeseed (Brassica napus L.)

In order to estimate relationship among rapeseed quantitative traits using correlation and regression coefficients, as well as to assess direct and indirect effects of specific traits to oil yield via path analysis, 14 rapeseed cultivars in two years were evaluated using randomized complete block design with three replications in Rice Research Institute of Iran, Rasht, Iran during 2005-2007 cropping seasons and 13 traits were measured. The results of combined analysis showed significant difference among years, genotypes and year× genotype for most studied trait that be indicated the existence of genetic variation among varieties. Oil yield had a significant positive correlation with grain yield, oil percent and grain weight, while had a significant negative correlation with DS. Results of stepwise regression analysis of oil yield showed that traits grain yield, oil percent and days to flowering had the highest effect on oil yield and was attributed 99.1% of oil yield variation. According to path analysis, grain yield and followed by oil percent had the highest direct effects on oil yield. Based on the results grain yield and grain weight was proposed as selective index to reach the high oil yield.