Study On The Fruit Characters Analysis And Genetic Diversity Of Prunus Mira (Koehne) In Tibet

In this study, Prunus mira (Koehne) from Tibet were used as the materials. The main fruit characters of Prunus mira (Koehne) were analysed and the genetic diversity of Prunus mira (Koehne) were assessed by SRAP makers. The results were as following:1. Prunus mira (Koehne) had high level of diversity. Prunus mira (Koehne) had the larger variation of appearance, high levels of soluble solids, soluble acid content, soluble sugar content and firmness with skin. And a small number of samples showed a good trend of rich flavor because of their sugar and acid compositions.In18fruit characters, firmness with skin and flavor two characters which both had5scales were at the highest level, fruit weight and soluble sugar content which had1scale were at the lowest level in grade index; the coefficients of variation of14characters were exceed20%, and the coefficients of variation of flesh color character was the highest.2.The orthogonal design was used to optimize the sequence-related amplified polymorphism (SRAP) reaction system for Prunus mira Koehne, which involved5factors, i.e. dNTPs, Mg2+, primer, template DNA and Taq DNA polymerase,each at5levels, and primers were screened. The results showed that an optimal25μL reaction system of SRAP for P. mira Koehne included2.5μL10×buffer,0.35mmol/L dNTPs,1.5mmol/L Mg2+,0.4μmol/L primer,20ng template DNA and2.5U Taq DNA polymerase.3. A total of376bands were amplified from70Prunus mira (Koehne) materials by20primers, of them,338SRAP loci were polymorphic, the percentage of polymorphic band was89.89%. According to the results of SRAP amplification, which were analyzed to Jaccard similarity coefficient by NTSYSpc2.10software, the genetic similarity coefficient was0.59-0.95, the average genetic similarity coefficient was0.78. UPGMA method clustering analysis displayed the genetic relation among the varieties. The genetic distance between47 and57was the farthest, while7and9was the nearest.4. Sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity and population structure of four natural Prunus mira (Koehne) populations from Tibet. A relatively high level of intraspecific genetic diversity were revealed: PPB(Percentage of polymoriphic loci)=89.89%, H(Nei’s (1973) gene diversity)=0.1943and I(Shannon’s Information index)=0.2955at population level; PPB=89.89%,H=0.2460and I=0.3839at species level. The Gst (Nei’s Gst analysis)=0.1709indicated a low degree of genetic differentiation occurred among Prunus mira Koehne population, but the gene flow among population was high to1.2130. The results of genetic diversity study, there were relatively high genetic diversity, low genetic differentiation and higher degree gene flow among Prunus mira (Koehe) population.5. The genetic distance among4populations was0.0217-0.1003. The clustering analysis showed that LZ population and CD population were in one group, and LS population and RKZ population separated from all the other populations in the dendrogram.