AFLP Molecular Marker Of Scab-resistance Genes Of Pears

During the entire lifecycle pear trees are affected by many diseases and pests, which can make severe losing of pear production, fruit quality and the economy benefit. Among them pear scab (Venturia nashicola Tanak et Yamamota) is one of the worldwide diseases on pears, and it has been spreading almost all pear production area in the world. In recent years, pear scab has been spreading by the development of pear production in China and more serious year after year. And it has been become the main restrictive factor affecting the pear production in China. So selecting the disease-resistance varieties has been one of the most economical, the most effective and the securest methods on controlling the diseases. DNA molecular markers are important genetic marker, which has been developed by molecular biology, and it develops quickly in recent years. DNA molecular markers have been widely applied to almost all aspects of fruit heredity and breeding, but not on pear scab yet.The disease-resistant variety 'Xinpingli' (P.bretschneideri) was used as the female parent and the disease-susceptible cultivar 'Xuehuali' (P.bretschneideri) as male parent in the study.The scab-resistance of the seedlings of 'Xinpingli' X 'Xuehuali' were investigated under both the natural condition and the scab-inoculated in the greenhouse. Acording to the resitance, Amplified fragment length polymorphism (AFLP) was used for screening the resistance genes. The system of AFLP on pear was established, and finally they were marked.For the system of AFLP on pear, CTAB was used as the DNA extracting method, and then subtracted RNA from the extracted DNA. Digested by EcoFJ/Msel and ligated, the genomic DNA was taken as the template for pre-amplification by E+0/M+C and 64 primes of the prime combination EcoRI+3/MseI+3 for selective amplification were suitable for the pear genomic DNA analysis.Bulked Segregation Analysis (BSA) was introduced for analysising the scab-resistance genes of the offsprings of 'Xinpingli' X 'Xuehuali' by 64 pairs of primers. The results showed that the primers combination of EcoRI+ACG/Msel+CAG amplicated 2 markes of pear scab-resiatance segments.