Studies On Genetic Diversity Of Germplasm Resource In Cerasus Tianschanica Pojark

Cerasus tianschanica Pojark is the precious ancient relic species at the end of the third age only distributed in Yili area and Tacheng area of Xinjiang in China.In this research,44 samples in 4 wild populations of Cerasus tianschanica Pojark from Yumin County,Teks,Kalajun and Daxigou were used as materials.Based on the observation of 16 morphological indexes and the measurement of diversity with SSR and ISSR markers,the genetic diversity level and genetic structure of Cerasus tianschanica Pojark germplasm resource were revealed,hoping to provide reference and theoretical basis for the protection and utilization of the germplasm resources of Cerasus tianschanica Pojark.The main research results were as follows:1.Based on the measurement of morphological index,we found that the Phenotypic variation coefficient,Simpson index and Shannon-weaver index of Yumin county population were all the highest,while those of Kalajun population were all the lowest.The mean phenotypic differentiation coefficient was25.77%,the variation was greater within populations than among populations.The fruit vertical diameter,fruit transverse diameter,stamen length,corolla diameter and petal length were the main causes of phenotypic difference.2.Through the effects of different preservation methods on the total DNA quality of Cerasus tianschanica Pojark leaves,we found that the high pure genomic DNA could be extracted with methods of-70? preservation,room temperature preservation,silica drying preservation and 2min-treatment in microwave preservation.The integrity genomic DNA could be extracted from the leaf stored in liquid nitrogen,and the clearer PCR amplified map could be obtained by using drying preservation methods.Taking many restrictive factors on wild sample into consideration,we think the silica preservation method is the suiTab.way in molecular biology research of Cerasus tianschanica Pojark.3.14 pairs of SSR primers from prunus were used to analyze the genetic diversity of Cerasus tianschanica Pojark,and 191 loci were detected by 14 pairs of SSR primers,including 148 polymorphic loci.Nei's genetic diversity(H)and Shannon's information index(I)were 0.2398 and 0.3676.The genetic diversity of Daxigou population was the highest.The Genetic differentiation coefficient(Gst)was 0.1935 and the Gene flow(Nm)was 2.0843,which revealed that genetic differentiation was at a low level and the gene exchanged frequently among populations.4.Using ISSR markers to analyze the genetic diversity of Cerasus tianschanica Pojark,we found that236 loci were detected by 26 pairs of ISSR primers,including 175 polymorphic loci.Nei's genetic diversity(H)and Shannon's information index(I)were 0.2073 and 0.3188.The Genetic differentiation coefficient(Gst)was 0.2282 and the Gene flow(Nm)was 1.6911,revealing that genetic differentiation was at a low level and the gene exchanged frequently among populations.In addition,the variation was distributed among individuals rather than populations,minimum genetic distance was observed between Kalajun and Daxigou population,and being clustered into one group.Daxigou population,compared with other populations,has the highest level of genetic diversity.