Diallel analysis of oil content and some agronomic traits in rapeseed (Brassica napus L.) based on the additive-dominance genetic model

摘要

Development of high oil content varieties is one of the most important aims of current rapeseed breeding programs. A set of 36 diallel F1 hybrids, their parents and four additional cultivars were evaluated in the breeding nurseries during 2008 and 2009. Plant height (PH), number of lateral branches per pod (NBP), main stem length, number of grains per pod, days to start of flowering (DSF), 1000 grain weight (GW), harvest index (HI), and oil content (OC) were measured. Diallel analysis was carried out considering the additive- dominance genetic model to estimate variance and covariance components. The additive genetic variance component was significant for NBP and DSF, the dominanace genetic variance for PH and the additive by year interaction for PH and OC. GW However, dominance by year interaction was significant for all characters under investigation and played a major role in the inheritance of these traits. This implies that the utilization of heterosis could be effective for the genetic improvement of oil content and agronomic traits in rapeseed in specific environments. Positive dominance effects of oil content were seen in Okapi × Orient and SLM046 × Opera crosses followed by SLM046 × Colvert and Fornax × Okapi combinations. Fornax, Talaye and Modena proved good general combiners and could be used for the improvement of oil content and agronomic characters. NBP, NGP and HI had significant effects on the oil content. These characters should be given more attention as the main traits of selection for the purpose of improving oil content in rapeseed.