Chinese Mulberry Genetic Diversity Analysis And Core Collection Building,

Morus cathayana Hemsl is one of 15 species of mulberry in china, is also one of the largest population in wild mulberry speciess . Morus cathayana Hemsl is widely distributed in China, Guizhou, Yunnan majority. After long-term natural selection, have adapted to a variety of local natural environment, the formation of a Chinese mulberry unique botanical and biological characteristics. The female flower does not have the style, the column head inside has the wool, also has the wool with to break out mixes lives. Diploid and polyploid have found that the majority of polyploid. Morus cathayana Hemsl has large leaves, leaves thick, drought, cold, alkali resistant, fast growing and so on.By the use of ISSR molecular markers, this paper carried out genetic diversity of research about Morus cathayana Hemsl.germplasm resources and constructed the core collection. It had an important practical value and theoretical significance to Morus alba Linn. in our country in the molecular identification, genetic improvement, protection, the important agronomic traits of gene mapping and molecular-assisted breeding. The main contents were summarized as the following:1,Genetic diversity of Morus cathayana Hemsl. based on ISSR analysisBy the application of ISSR markers, it was carried out the genetic diversity analysis of the 60 germplasms of Morus cathayana Hemsl. By use of PopGene 32 software, it was caculated the genetic similarity coefficient of the 60 germplasms of Morus cathayana Hemsl.and made a cluster analysis by UPGMA. The resulits of ISSR polymorphism analysis were as follows. By using 13 specific and stable primers, a total of 118 bands were amplified, with 106 polymorphic bands, that is about 89.8% of which. Genetic similarity coefficient were changed from 0.1335～0.837. The average of Nei's genetic similarity coefficient was 0.520. Evenly, each loci owned that the observed number of alleles,effective number of alleles, Nei's gene diversity,Shannon's information index and total gene diversity for the species was 2.000, 1.6224, 0.3565, 0.5289, 0.3565 respectively. This indicated that there were the large ISSR variation and high polymorphism between the 60 mulberry materrials of Morus cathayana Hemsl.germplasm. Clustering results showed that the Morus cathayana Hemsl. germplasms could be divided into two differrent large categories obviously.2,Constructing the Core Collection of Morus cathayana Hemsl.By using stepwise clustering and random methods and the modified heuristic algorithm to construct core collection of 60 Morus cathayana Hemsl. germplasm resources, it contained 16 and 15 core collections of Morus alba Linn. and the ratio of core collection samples were 26.67%,25.00% respectively. By using statistical software SPSS13 and combining with molecular markers polymorphic loci, percentage of polymorphic loci, observed number of alleles, effective number of alleles, Nei's genetic diversity index and Shannon's information index to evaluate and make t test of two groups core collection, the results showed that the 16 and the 15 core collections of Morus cathayana Hemsl.could conserve the genetic diversities and structures of the primary collection better, but the 15 core collections was superior to the 16 core collections. Finally, the 15core collections were identified as the core collction of Morus cathayana Hemsl germplasm.