Research On Genetic Diversity And Construction Of Core Germplasm By SRAP In Xinjiang Juglans Regia L

Xinjiang Juglans regia L. is the progenitor of China’s cultivated juglans. In the world Juglans regia L. was largeley planted only in two areas and Gongliu County which is located in Xinjiang is one of the areas. Xinjiang Juglans regia L. forest is a rare wild plant resource in China, but only a little studies were done on Juglans regia L. in China.SRAP markers was used to study genetic diversity and construction of core germplasm of Xinjiang Juglans regia L.. The phylogenetic relationships among Juglans regia L. was found through the analysis of genetic parameters. This provided the molecular basis for the utilization of Juglans regia L. germplasm resources in Xinjiang and genetic map construction. Scientific basis was provided for the scientific and effective conservation, evaluation and identification of Xinjiang Juglans regia L..1. SRAP reaction system of Xinjiang Juglans regia L. was established. Finally 15 pairs of SRAP primers were selected. In 20μL SRAP reaction system, DNA was 50 ng, primers was 0. 4μmol/L, Mg2+ was 2mmol/L, dNTPs was 0. 2 mmol/L and Taq polymerase was 0. 5U. Residual volume was filled with double distilled water. The 15 pairs of primers were used to amplify Xinjiang Juglans regia L.’s DNA. The results showed that the amplified DNA polymorphism was rich and had good repeatability.2. Through the research and analysis of Xinjiang Juglans regia L. germplasm resources and genetic diversity, the average value of 15 pairs of different primers combinations sites Nei’s diversity index was 0. 3868. The average value of Shannon’s diversity index was 0. 5720 and the percentage of polymorphic loci was 94. 07%, which illustrated polymorphism was very rich in each primer combinations site. The average value of gene differentiation coefficient(Gst) was 0. 1152, which showed that the middle differentiation of the Juglans regia L. population in Xinjiang was medium. The total genetic diversity of Xinjiang Juglans regia L. was 86. 61%, which showed the total variation of Juglans regia L. in Xinjiang mainly existed in region.3. Analyzing the data from Nei’s by clustering method, the results showed that when the genetic distance was fixed, Juglans regia L. could be classified into two categories and the classified populations were similar in region.4. The core collection of Xinjiang Juglans regia L. was constituted by 48 samples and the sample proportion was 1. 14% of the original germplasm. T-test results showed that at the level of 0. 05, the collected core collection and the original germplasm had no significant difference and the retention rate of core germplasm in Ne, Nei’s and shannon ’s index were 100. 01%, 100. 02%, 100. 02%, which indicated that the core collection of the Juglans regia L. can well represent the polymorphism of the original germplasm. The 48 core collection included the smooth degree of bark of the original germplasm of Xinjiang Juglans regia L., the height of tree, the colour and lustre of branches, the disease(insect pests), the fruit shape and the order of flowering, etc.