Analysis Of Genetic Diversity On Germplasm Resource Of Walnut (Juglans Regia L.) In Xinjiang

Walnut (Juglans regia L.) is a species belonging to the genus Juglans, which is an important nutritional nut. However, with the development of walnut industry and the unplanned extension of new varieties, some wild species genetic resource have disappeared gradually, walnut species can develop simplification tendency. So, it is necessary to investigate the genetic diversity and genetic structure of walnut resource in existence by genetic marker and provide some theoretical information for further conservation and utilization. In this study,the genetic diversity and genetic structure of 6 walnut populations (total 163 walnut samples) which were distributed in Hami, Shanshan, Tulufan, Gongliu, Huocheng and Wensu were shown with the marker technique of ISSR and RAPD, and which revealed the different walnut populations of the genetic diversity and gene differentiation. In addition, the research obtained the RAPD marker related to character of precocious walnut, with the RAPD marker converted into the peculiar of SCAR marker. The main results are the below:1. The 13 ISSR primers employed produced a total 117 loci amplified fragments, of which 98 are polymorphi and the percentage of polymorphic loci (PPL) was 83.76%. Analysis genetic diversity by ISSR showed that the Nei's genetic diversity (H) was 0.3010, the Shannon-Weaver index (I) was0.4182, the coefficient of gene differentiation (Gst) was 0.6425; the effective number of migrants (Nm) was 0.2782. Different populations have different genetic diversity, Wensu walnut population have a higher level genetic diversity, and Gongliu walnut population have a lower level genetic diversity. The results of AMOVA indicated that the variance components within populations and among populations contributing to total genetic variance were 29.45% and 70.55%.UPGMA and Mantel analysised that 6 populations have a higher the genetic correlation, r was 0.6144.2. The 18 RAPD primers employed produced a total 192 loci amplified fragments, which are 154 polymorphi and the percentage of polymorphic loci (PPL) was 80.21%. Analysis genetic diversity by RAPD showed that the Nei's genetic diversity (H) was 0.3185, the Shannon-Weaver index (1) was 0.4830, the coefficient of gene differentiation (Gst) was 0.5095; the effective number of migrants (Nm) was 0.4814. Different population have different genetic diversity, Wensu walnut population have a higher level genetic diversity, and Gongliu walnut population have a lower level genetic diversity. The results of AMOVA indicated that the variance components within populations and among populations contributing to total genetic variance were 48.00% and 52.00%.UPGMA and Mantel analysised that 6 populations have a higher the genetic correlation, r was 0.5307.3. There is a higher correlation between the two sets of similarity parameters calculated with ISSR and RAPD data, and detected that Xinjiang walnuts have a higher level of genetic variation both at species and population level.4. Screened the molecular marker linked to character of precocious walnut, and successfully converted the RAPD marker into the peculiar the marker SCAR.