Inheritance of Winter Oilseed Rape Fatty Acid under Normal and Late Sowing Conditions

To study of inheritance of oilseed rape quality traits in normal and late sowing date conditions, 31 genotypes including 7 winter lines as females, and 3 winter testers and their 21 F1 generation were grown under normal sowing date (early October) and late sowing date (early November) conditions in two separate RCB designs with two replications at the field of Seed and Plant Improvement Institute, Karaj (2011-12). Combined analysis of variance showed significant differences between treats of oil seed content and most fatty acids traits in both sowing dates. Therefore, significant genetic variation existed for all traits among the genotypes studied. Estimates of broad and narrow heritability of most traits under late sowing date were less than the normal sowing date and this was mainly due to less esti mation of variance components under late sowing date conditions. In addition, broad heritability was estimated to be generally medium to high (between 72.01 to 100) in both normal and late sowing date conditions. The narrow heritability of traits in both sowing conditions ranged from 20.81% to 80.20%. Therefore, selection for traits with moderate to low narrow heritability in early generations would not be much useful, and it is preferable to use heterosis to improve these traits. In both sowing dates non-additive effect was more evident in control of quality traits. Therefore, selection for these traits would not be effective without using the effect of gene dominance.