Genetic Analysis of Resistant to Powdery Mildew with Mixed Model of Major Gene Plus Polygene in Wild Melon Material 'Yuntian-930'

Objective) The inheritance law of powdery mildew resistance in wild melon material 'Yuntian-930' was studied for utilizing this resistance material and providing a theoretical basis for selecting resistance gene in melon breeding. (Method) Six populations (P1, P2, F1, B1, B2 and F2) derived from the cross of 'Yuntian-930'× 'Hualaishi' with the highest resistant germplasm 'Yuntian-930' and the highest susceptible germplasm 'Hualaishi' were used to study the inheritance of powdery mildew resistance by the mixed major-gene plus polygene inheritance mode with joint analysis method of multiple generations. (Result)The result showed that the inheritance of powdery mildew resistance of wild melon'Yuntian-930'fitted two pairs of additive-dominance-epitasis major genes plus additive-dominant-epitasis polygene model (E-0 model). In 2008, the major genes heritability of B1, B2 and F2 were estimated to be 73.31%, 69.15% and 97.61%, respectively, the polygene heritability to be 18.83%, 25.86% and 0, and the ratios of the environmental variance to phenotype variance were 2.39%-7.86% in the plastic greenhouse. In 2009, the major genes heritability of B1, B2 and F2 were estimated to be 62.98%, 58.58% and 90.89% respectively, the polygene heritability to be 28.93%, 31.47% and 3.22%, and the ratios of the environmental variance to phenotype variance were 5.89%-9.94% in the greenhouse. (Conclusion) The powdery mildew resistance of wild melon 'Yuntian-930' was controlled by two pairs of additive-dominance-epitasis major genes plus additive-dominant-epitasis polygene, and also affected by environment. In the resistance breeding program, the selection efficiency to major gene of the F2 is the highest.