Genetic Diversity Evaluation Of Shazikongxin Plum Germplasm Resource

Prunus salicina’Shazikongxinli’belonging to the Rosaceae family of the genus Prunus,is a local plum variety cultivated in Yanhe County,Tongren City,Guizhou Province,currently mainly planted in a few areas such as Shazi Street in Yanhe County.In addition,it has been listed as a national geographical indication product of China and awarded the designation of"China’s Quality Plum".’Shazikongxinli’is an important agricultural industry and a key project for poverty alleviation in Yanhe County.There are uneven fruit quality and inconsistent fruit maturity,which are not conducive to the industrial development of’Shazikongxinli’,but at the same time,the diversity of’Shazikongxinli’germline also provides a germplasm resource base for the excavation of excellent germplasm.In this paper,we used morphological markers and three molecular markers（ISSR,IRAP,and SSR）to analyze the genetic diversity of 68plum germplasm（50’Shazikongxinli’as the experimental group,18 other plum species as the control group）and used IRAP markers to construct fingerprint profiles of 125 representative germplasm of’Shazikongxinli’.The results were as follows:1.Morphological marker analysisA total of 43 morphological traits were counted in 68 plum germplasm,including32 qualitative traits and 11 quantitative traits.The mean Shannon-Weaver diversity index（H’）for the 32 qualitative traits in the 50’Shazikongxinli’was 0.557,and the mean coefficient of variation（CV）for 11 quantitative traits was 15.57%,which was lower than the results for 18 other plum varieties（H’=0.811,CV=26.89%）.Traits such as new shoots color,leaf area,weight per fruit,fruit hardness,and seed weight showed a high level of diversity in 50’Shazikongxinli’.The clustering of morphological markers divided the 68 plum germplasm into two clusters,with Cluster I containing 50’Shazikongxinli’and four other plum varieties（Cuihong plum,Red heart plum,Fongtang plum,and Xingxing plum）and Cluster II containing fourth other plum varieties.2.ISSR marker analysisOne hundred forty-one loci were amplified by the 15 ISSR primers in 50’Shazikongxinli’,which included 105 polymorphic loci,with an average of 9.4 loci per primer,average polymorphism loci of 7.0,and an average polymorphism ratio of73.5%.Meanwhile,15 ISSR primers amplified 155 loci in 18 other plum varieties,including 136 polymorphic loci.The average polymorphism ratio was 86.4%.The number of alleles observed（Na）,number of effective alleles（Ne）,Nei’s gene diversity（H）,and Shannon information index（I）of the 15 ISSR primers in 50’Shazikongxinli’were 1.735,1.137,0.100 and 0.176,respectively,which were smaller than the 18 other plum varieties in the control group（Na=1.864、Ne=1.366、H=0.236、I=0.375）.3.IRAP marker analysisTwenty two IRAP primers generated 249 loci in the experimental group,which included 232 polymorphic loci,with an average amplification loci number of 11.3 and an average polymorphic locus of 10.6,and an average polymorphism ratio of 90.7%.Meanwhile,261 loci were amplified by 22 IRAP primers in the control group,with249 polymorphic loci,and an average polymorphism ratio of 93.3%.The average Na,Ne,H,and I values of the 50’Shazikongxinli’were 1.907,1.409,0.255,and 0.397,respectively,which were lower than the results of the 18 other plum varieties（Na=1.933,Ne=1.477,H=0.292,I=0.449）.68 plum germplasm in the IRAP marker clustering results were divided into two clusters;Cluster Ⅰ consisted of 52 germplasm,including 50’Shazikongxinli’,Red heart plum,and Xingxing plums,while Cluster Ⅱ included 16 other plum varieties.4.SSR marker analysisTen pairs of SSR primers amplified 83 loci in the experimental group,including 66polymorphic loci,with an average polymorphism ratio of 79.5%.In the control group,103 loci were amplified by ten pairs of SSR primers,with 99 polymorphic loci,an average polymorphism ratio of 96.1%.The 68 germplasm were clustered into three clusters,of which Cluster Ⅰ included 50’Shazikongxinli’and four other plum varieties（Fengtang plum,Qingcui plum,Yuhuang plum,and Sanyue plum）,while Cluster Ⅱ and Ⅲ contained 4 and 10 other plum varieties,respectively.The correlation analysis among the three molecular markers showed that the correlation coefficient between ISSR and IRAP markers was r₁=0.605,and between SSR markers and ISSR and IRAP markers were r₂=0.902 and r₃=0.611,respectively.5.Fingerprint profile of’Shazikongxinli’Thirteen IRAP primers were selected to identify 125 representative germplasm of ’Shazikongxinli’,among which primer Ty3-2 had the highest identification ratio and could identify 103.The combination of primers Ty3-2 and Ty3-6 could identify all the germplasm,and the fingerprint codes of 125 germplasm were constructed from the0/1 data of these two primers.Then barcodes and 2D codes were generated,including information on germplasm cultivation place,salient traits,and fingerprint codes.