Analysis of the qualitative-quantitative genetic models of whiteflower color with petal pigments quantification in Brassica napus L.

White flower color is a useful indicator in Brassica napus L.It was used in correlative selection and purity test,and was also used as a genetic trait marker.In the present study the petal pigments of rapeseed were extracted and quantified by a spectrophotometer at 493nm in order to investigate the genetic model of flower color.Six generations(P1,P2,F1,F2,B1 and B2) from both of two crosses between white-and yellow-flowered rapeseed lines(HW243×HZ21-1 and HW243×Zhongyou 821) were analyzed with a mixed genetic model for major genes and poly genes.Results showed that white color in rapeseed was a quantitative trait,and its inheritance fitted to a mixed genetic model of two major genes with additive-dominant-epistatic effects plus polygenes with additive-dominant-epistatic effects(E-0 model).Among them,the additive,dominant and epistatic effects of the two major genes were equally important.The effects and heritability of major genes were high with low environmental influence,and that of the polygenes were also relatively low.The estimated heritability rates of the two major genes were 95.51% and 96.35% in F2,53.00% and 49.59% in B1,97.38% and 95.51% in B2,respectively.The estimated inheritability rates of the polygenes were 3.65% and 2.43% in F2,39.93% and 39.84% in B1,2.17% and 1.57% in B2,respectively.