Evaluation of seed and oil yields and their components and relationships in oilseed rape genotypes under East Azarbaijan conditions in Iran

Seed and oil yields, their components, and the relationships among trait performance were determined in 25 genotypes of winter type oilseed rape (Brassica napus L.). The experiment was carried out at the Agricultural and Natural Resources Research Center of East Azerbaijan, Iran, in two consecutive growing seasons 2009-10 and 2010-11. Significant differences were observed in plant height, number of pods per plant, number of seeds per pod, 1000-seed weight, harvest index, and seed and oil yield. Cluster analysis divided the genotypes into two groups based on the studied traits. One group consisted of 16 genotypes with low and the other included 9 genotypes with high seed and oil yield. Based on observations, genotypes SW102, HW101, HW111, L62, L72, L139, SW104, Karaj1, and Karaj2 showed high seed and oil yields and would therefore be suitable for the Tabriz plain and areas with similar conditions and for selecting genotypes tolerant to environmental stress. A positive correlation was found between plant height and number of seeds per pod, and seed and oil yields. Number of pods per plant contributed more to seed yield among seed yield components. Harvest index and 1000-seed weight had the highest and the lowest indirect effects on oil yield, respectively. It appears that harvest index and plant height are important features for selecting winter type oilseed rape genotypes for Tabriz plain and areas with similar conditions.