Heritability and Gene Action of Different Traits in Spring Oilseed Rape using Diallel Analysis

Oilseed rape is one of the most important oilseeds in Iran. Due to limited genetic resources, the development of its cultivated area requires genetic diversity by hybridization in breeding programs and, finally, introducing potential lines to the agricultural community. Therefore, this study aimed to generate genetic diversity by hybridizing eight spring rapeseed genotypes using a complete diallel design and investigating the inheritance and genes action of some agronomic traits, yield, and its components in F1 progeny in a complete block design with three replications in 2018- 2019 and 2019-2020 crop years. Analysis of variance components showed that the mean squares of general combining ability were significant only for branching height, podding height, pods per lateral branches, and pods per plant. In contrast, mean squares of specific and reciprocal combining ability were significant for all traits. The highest and lowest values of sprecific heritability obtained for podding height (18%) and grain per pods (0.4%), respectively. The GCA/SCA ratio also indicated the importance of additive effects for branching height, podding height, pods per lateral branches and pods per plant. Parents SPN-182 and SPN-202 had a positive and significant general combining ability for lateral branches, pods per lateral branches, pods per plant, grain per pod and grain yield. SPN-207×SPN-182 and SPN-206×SPN-182 hybrids with the highest positive and significant specific combining ability are essential for grain yield traits to produce single cross hybrids.