AFLP Assessment Of Genetic Diversity Of Potato Germplasm Resouces

Potato (Solanum tuberosum L.) is the world's third most important crop after rice and wheat. Potato is not only a main food crop but is industrial raw material. In this study, genetic diversity of 123 potato germplasms which were from the International Potato Center (CIP) and the main part of Qinghai Province cultivars were analysed by AFLP.The aim is that provided the theoretical basis with potato breeding.The results are as follows:1. The digestion and ligation, amplification system and silver staining proce- dures of AFLP were optimized. A system suitable for the genetic diversity of potato AFLP was established: DNA 160 ng, 37℃digestion ligation 12h; In the pre-amplification system, dNTP concentration of 0.2mmol/L, Taq DNA polymerase 1U; In the selective amplification system, amplification products were diluted 20 times, the final primer concentration of 2.5 ng / uL.2. Using the optimized system, 10 primer pairs from 81 primer combinations were selected on the polymorphism: E42/M48,E42/M59,E35/M62,E39/M49,E39/M59,E42/M54,E37/M49,E36/M61,E36/M54 and E36/M62.3. The genomic DNA of 123 cultivars of potato were amplified by 10 pairs of AFLP primers,and 521 clear bands were produced,of which 488 were polymorphic.The average percentage of polymorphism was 93.6%,which indi cated that potato cultivars has higher genetic diversity.4. The genetic similarity coefficient (GS) of 123 potato materials ranged between 0.59 and 0.97. Based on material similarity coefficient, the tested materials were clustered, in the genetic similarity coefficient of 0.78, all materials were divided into 13categories: the first category contained 62 materials, accounting for 50.4% of the tested materials and include 85% domestic cultivars,the 13th category contained 44 CIP potato resources with resistance to late blight, accounting for 78.5% of all the resources with resistance to late blight. 5. Germplasms from CIP have plentiful diversity.Domestic potato cultivars have poor genetic similarity, neared genetic relative and narrowed genetic basis. The basis of domestic potato would be aplified by CIP resources.6. Cultivars from Qinghai have more genetic variance, lower genetic similarity than domestic cultivars and CIP resources. The CIP resources and domestic cultivars could be applied in potato breeding in future.