Abstract:

Cultivated Potato(Solanum tuberosum subsp. Tuberosum) is planted widely in China. The origin of germplasms is varying complicated and disordered at present. Many researches have paid their attention to potato genetic diversity by shape and biochemistry analysis，while studies on molecular genetic diversity were few in China. Using RAPD and AFLP methods, the genetic diversity of 71 Chinese main potato cultivars was analyzed. Comparing with the amplified results of RAPD and AFLP markers, each primer combination of AFLP identified 100.1 loci averagely, among which 54.9 were polymorphic(Table 3), while each RAPD primer only detected 12.5 loci, of which 9.8 were polymorphic(Table 2). The Shannon-weaver index and Simpson index from AFLP were all higher than those from RAPD indicating the genetic diversity identified by AFLP was higher than that by RAPD(Table 4). There were differences between the two methods in genetic diversities, due to different principles of AFLP and RAPD, and some cultivars were clustered into different groups. However the results showed that both of the two methods could identify the 71 potato cultivars， which were clustered into 3 to 4 groups(Fig.1, Fig.2). Analysis of average genetic distance by AFLP and RAPD suggested that the kinship is close among 71 Chinese main potato cultivars, which indicate that the genetic basis of potato germplasm in China is narrow. The relationships of cultivars showed by the results were identical to the family tree basically. Due to the simple technique and low cost, RAPD is more suitable to distinguish cultivars and seed potato purity. In genetic diversity analysis, more methods should be used to conform one another to draw correct conclutions.

Key words: Solanum tuberosum, Genetic diversity, RAPD, AFLP