Genetic Relationship And Population Structure Of Plum In The Sichuan Province In China Based On SSR Markers

Plum is a Prunus plant of the genus Prunoideae which belongs to the Rosaceae,which is important stone fruit tree in China.The history of growing plums in Sichuan with at least 2000 years,the germplasm resources of plum are abundant.Sichuan is one of the important economic production areas.The research on plum is more concentrated in pest control and industrial development.Molecular biological markers have little research on the genetic characteristics of Sichuan plum germplasm resources.In this study,SSR marker was used to analyze the genetic relationship,genetic diversity and population genetic structure of Sichuan plum germplasm resources,in order to provide a theoretical basis for the evaluation,identification and breeding of plum germplasm resources in Sichuan and Southwest China.The main results and conclusions are as follows:1.The average polymorphism information content(PIC)of 22 pairs of primers for 63 cultivars was 0.5648,and the average PIC value of 20 pairs of primers used in populagtion genetic structure analysis was 0.507.The major allele frequencies(MAF)of all locus were less than 95%,which indicating all the primers wtih high polymorphism and could be used for the research of Sichuan plum germplasm resources.2.The results of the genetic diversity analysis of the materials indicated that a total of 114 alleles were successfully detected with 22 pairs of SSR primers in 63 plums.The number of alleles(Na)and effective alleles(Ne)were ranged from 2 to 9 and 1.1711 to 6.9534,wtith the average values were 5.1818 and 3.1532,respectively.The expected heterozygosity(He)and observed heterozygosity(Ho)were ranged from0.0635 to 0.9524 and 0.1473 to 0.8639,with the average values of 0.5711 and 0.6870,respectively.Shannon’s information index(I)and Nei’s gene diversity(H)were ranged from 0.2772 to 2.0368 and 0.1461 to 0.8562,the mean values were 1.2122 and0.6045,respectively.These data indicate that the 63 materials with moderate to rich genetic diversity.3.22 pairs of primers can completely separate 63 plum cultivars(strain),Ziyeli with Jianganli and Huangjiabaoshili,Bingtangli and Siyueli are far from each other.Different maturity of Santaituli were almost identical in genetic background.Cuihongli and Qingcuili had some genetic changes during the introduction and cultivation of each other.Three Yuhuangli from different areas(Pujiang,Wenchuan,Hanyuan)was homonym.4.Genetic diversity was moderate within Sichuan plum populations.The average number of genotypes,observed number of alleles,effective number of alleles,Shannon’s information,observed homozygosty,expected homozygosty,Nei’s gene diversity were 2.045,2.640,1.987,0.671,0.637,0.434 and 0.413 respectively.The highest level of genetic diversity was in the pop2 population,while the lowest was in the pop3 population.5.According to STRUCTURE and UPGMA cluster analysis,10 plum populations could be divided into 3 genetic clusters,Pujiangtuli is a group,Wenchuancuihongli and Pengshantuli are a group,and other 7 populations are one group.6.Molecular analysis of variance(AMOVA)analysis showed that 13.51%genetic variation was among the populations,which indicate that the level of genetic differention among population is moderate,while,a high genetic variation(86.49%)within popuplation.