Abstract:The mixed major-gene plus polygene inheritance model was used to analyze the inheritance of leaf lobes in Brassica rapa with six generations of P1 (smooth leaf margin inbreed line)and P2 (leaf margin nick inbreed line)and their F1,B1,B2 and F2.The result shows that the number of leaf lobes is controlled by two major genes with additive-dominance-epistatic effects plus poly-genes with additive-dominance effects (E-1 model)in hybrid.The additive effects of the two major genes are -1.154 7 and -1.154 8,respectively,and the dominance effects of the two major genes are -1.516 8 and 1.034 9,respectively;The heritability of the major genes in B1,B2 and F2 are 88.48%，90.40% and 93.03%,respectively,but the polygene heritability only be checked in B1,which is 4.114%.It indicated that the leaf lobes in B.rapa was dominated by major genes.This implies that in the genetic improvement of leaf lobes trait major gene is the main factor.It is fit for early selection.
