The Genetic Mechanisms Of Resistance To Powdery Mildews And AFLP Marker Linked To The Disease Resistance In Melon

Melon (Cucumis meloL.) is a valuable cash crop grown throughout the world. It is a member of the genus Cucumis, in the family Cucurbitaceae. And it is liked by worldwide people because of its good taste and rich nutrition. China is an important country of melon production, and the growth area have been getting more and more as the development of greenhouse planting. Powdery mildew is one of the most destructive diseases in melon production both in field and in greenhouse. Conventionally, people prevent the disease by using big deal of chemical pesticide which will reduce the quality of the melon. Resistant breeding is an efficient approach to control diseases and reduce fungicide use. Resistance breeding of melon needs the guidance of genetic mechanism. Molecular marker study is beneficial to further understanding of genetic information, management of germplasm, breeding and protection of new varieties.In this experiment, we studied two crosses of melon materiasl, and confirmed the powdery mildew genetic mechanism of the materials. Furthermore, we found an AFLP marker linked to the susceptible gene by AFLP method. The main results were as follows:The genetic mechanism of resistance to melon powdery mildew was studied with joint analysis of multiple generations. The best fitted model of two powdery mildew resistant × susceptible crosses 7-2×7-1 and 7-2×7-3 were all the same, which was two major genes inheritance model (B-1). The heritability of major genes of cross 7-2×7-1 in autumn 2004 was 96.32%, and it was 93.27% in spring 2005. For the cross 7-2×7-3, the heritability of major genes was 98.22% in autumn 2004 and 94.67% in spring 2005.A highly stable and optimized AFLP protocol which is suitable for melon was established. 70 polymorphic primer pairs between parents were screened out from 128 pairs.Based on BSA method, AFLP technique was employed to identify marker linked to melon powdery mildew resistance. M60E25-520 marker correlated to powdery mildew was detected. Molecular marker and phenotype of F₂ population were analyzed by correlation analysis. The results showed that it is extremely significantly correlated between...