Identification Of Molecular Markers Linked To Anthracnose Resistance Gene In Watermelon

Watermelon is a world horticultural crops,plays an important role in agricultural production. With the watermelon cultivation area extends continuously and diversification of planting mode, it caused many illness in watermelon.The watermelon anthracnose caused by Colletotrichum orbiculare throughout the world, it made great lose in watermelon produce in the world. It severely limited the watermelon yeild production and quality. Developing disease resistant watermelon varieties is the most economic and efficient method. Using molecular marker technology screening molecular markers tightly linked to the resistance gene, which has great significance for the breeding.In this paper, we use PI189225,Black Diamond F1and F2as basis materials, by using AFLP and SSR techniques to find molecular markers tightly linked to the resistance gene, which to provide a good foundation for watermelon anthracnose resistance breeding. The results of this paper are as follows:1.PI189225is resistance material and Black Diamond is susceptible materials. Their sexual hybridization F2population at seeding stage as test material were analyed through inoculation with Colletotrichum lagenerium. The response patterns showed that Resistance:Susceptible segregation ration for3:1, suggesting that the resistance gene was a single dominant gene.2.The method of CTAB was used to extract high quality genomic DNA. An efficient and stable AFLP analysis system was established for watermelon, which was done by selection and optimization in the aspects of DNA extraction, enzyme digestion and ligation,preamplification and selective amplification. The results indicated:There was about500ng DNA template, EcoR I10U, Mse Ⅰ5U, in the best system of restriction at37℃for4h. The optimum temperature in the lingation system was16℃for4h. Pre-amplification product was diluted10times.3.32×32AFLP primers combinations and279SSR primers combinations were screened in PI189225, Black Diamond and F1.43AFLP primers combinations and7SSR primers combinations were found. Using the primer combinations to develop marks in F2population. Three AFLP markers linked to the resistant gene were obtained, which genetic distance was34.8cM,23.4cM and6.9cM.