Dynamic gene expression analysis of maternal, cytoplasmic and embryo genetic systems for linolenic and erucic acid contents in rapeseed (Brassica napus L.)

The genetic effects including genetic main effects and genotype × environment (GE) interaction effects were analyzed for linolenic acid content (LLAC) and erucic acid content (EAC) in rapeseed using unconditional and conditional genetic models for diploid seed quantitative traits. The results from unconditional analysis revealed that GE effects were important for both traits during seed development. Also the higher magnitude of embryo effects at different developmental times indicated that seed selection would be useful for improving these quality traits in rapeseed. The conditional analysis showed that new expression of genes from maternal and embryo genetic systems occurred during different developmental stages and their magnitude could be influenced by the GE effects. The total narrow-sense heritability was high for both LLAC and EAC, with general heritability being more prominent for EAC at 15 days (32.87 %), 29 days (31.44 %), 36 days (60.55 %) and 43 days (76.45 %), and GE interaction heritability dominating for LLAC at 22 days (40.57 %), 29 days (60.91 %), 36 days (63.83 %) and 43 days (47.45 %) after flowering, respectively. Phenotypic and genotypic correlations for both traits were positive among some pairwise developmental times indicating that genes expressed at these times complemented each other to improve LLAC or EAC in rapeseed. Significant negative correlation between LLAC and EAC at most developmental times indicated that it may not be possible to simultaneously reduce the contents of both traits by indirect selection.