Abstract:

Resistance to sclerotinia sclerotiorum (Lid) de Bary in cross of DH821×DHBao604 (Brassica napus L.) was identified by mycelial toothpicks and petals inoculations, and the inheritance of resistance in this cross was analyzed by applying the major gene plus polygene model of quantitative traits to a joint analysis of multi-generations (P₁, P₂, F₁, BC₁, BC₂, F₂). The results showed that resistance measured 3 d after mycelial toothpicks inoculation was controlled by 2 pairs of major genes with additive effects plus polygene with additive-dominant effects. Heritability values of the major genes of BC₁, BC₂, and F₂ populations were from 12.49% to 28.48%, while these of polygene were from 21.08% to 27.87%. Resistance measured 5 d after inoculation was controlled by 2 pairs of major genes with additive-dominant-epistatic effects, among which dominant and associated epistatic effects were significant. Heritability values of the major genes of BC₁, BC₂, and F₂ populations were from 25.19% to 38.69%. Resistance to expansion of mycelia during 3－5 d after inoculation was controlled by 2 pairs of major genes with significant additive-dominant-epistatic effects plus polygene with low additive-dominant effects. Heritabilities of major genes and polygene in BC₁, BC₂, and F₂ populations were from 0.72% to 54.06% and from 7.34% to 46.79%, respectively. Resistance detected 15 d after infested petals inoculation was controlled by 2 pairs of major genes with additive-dominant-epistatic effects plus polygene with additive-dominant-epistatic effects. The additive and dominant effects of the major genes were from －3.605 to －3.5225, and the interaction effects from 3.5190 to 3.6089. Heritability of major genes and polygene in BC₁, BC₂ and F₂ populations were from 0.91% to 41.79% and from 19.32% to 73.69%, respectively.

Key words: Brassica napus L., Sclerotinia sclerotiorum (Lid) de Bary, Identification resistance, Inheritance