Analysis On Genetic Relationship Of 'LuGuo-2'

Juglans regia L. belongs to walnut genus (Juglans) of walnut family (Juglandaceae) with great economical values, and new varieties play an extremely important role in promoting walnut industrial development. As all we known, Juglans regia L. is a perennial woody plants. With long hybrid breeding cycl, the loss of parents'information is commom because of the substitution and change of breeding garden and the mission of test records, which bring difficulties to the intellectual property protection, breeeding pedigree establishment and further understanding of the fine properties'forming mechanism and genetic regularity. Therefore, the simple efficient and quick method to identify walnut paternity is necessary and urgent with walnut as research object.This study adopts eight stable expressional phenotypes, ten SSR primers and eight AFLP molecular markers to do paternity test on'LuGuo-2'and its six possible parents ('XiangLing','YuanFeng','LuXiang','FengHui', and'ShangSong-6'), with'Slz-40'and its parents'LuXiang'as reference. We established walnut paternity test method based on this study, and the main results are the below:In phenotypes parent-child analysis, the maximum and the minimum of kernel weight and nut weight had a obvious difference, while the other phenotypes had a amall differences. The nuts phenotypes'matrix correlation analysis of nine walnut varieties is 0.994~1.000 and the nuts phenotypes'matrix correlation analysis between'LuGuo 2'and its putative parents is 0.998~1.000, which shows that the phenotypes between nine walnut cultivars had a small difference and a close genetic relationship, so we cannot identify progeny s'parents through the nuts phenotypes.Ten SSR primers were selected from 32 reported black walnut SSR primers, they had simple clear stripes and high polymorphic unit phoints. The study detected 47 alleles by testing 20 walnut cultivars useing ten SSR loci. The WGA-070 locus detected 7 alleles and the WGA-071, WGA-118 locus detected 3 alleles. The average number of alleles for 10 SSR loci is 4.7. The progeny 'SLZ-40' and its known parents'LuGuang'accorded with the mendelian law through analysis of SSR genotypes. The genetics among putative parents'FengHui','YuanFeng','XiangLing''DaiFeng'and'LuGuo-2'violated genetic regularity and the progeny appears totally different alleles sites from parents, which eliminated the genetic relationship between them;'ShangSong-6'. The genetics between'LuXiang'and 'LuGuo-2' accord to the mendelian law, so they may had paternity. In extremely close walnut varieties paternity test of small difference in phenotypes, application of this method can identify progeny's parents.SSR clustering analysis showed that nine varieties divided into two groups(SG1 and SG2) with'XiangLing'forming a single group(SG2) and other varieties forming SG1. In SG1'LuGuo 2'and'ShangSong-6','LuXiang'clustered a group and'SLZ-40'and'LuGuang'clustered a group in 0.91 site, which further proved the reliability of this SSR paternity testing method.Eight AFLP primers were used to analyze parent-child relationship in nine varieties and 1480 bands were amplificated with average 185 bands for each primers.'LuGuo-2'and'YuanFeng'had the most similar genetic similarity coefficient (0.9026), followed by'LuXiang'(0.9005), thirdly by'ShangSong-6'(0.8978) while the other putative parents and'LuGuo-2'had a obviously less genetic similarity coefficient. In AFLP clustering analysis results, nine varieties can be divided into three groups (set to AG-1, AG-2, AG-3),'SLZ-40'and'DaiFeng'formed AG-1,'FengHui','LuGuang'and'XiangLing'formed AG-2 and the rest of the species formed AG-3. The AFLP clustering analysis is line with genetic similarity coefficient analysis. This study used AFLP to find three walnut varieties with most close relationship with'LuGuo-2', but failed to judge which two were its parents. At the same time, the reference analysis results were inconsistent with the actual situation, which shows that the application of AFLP in extremely close walnut varieties'paternity test need to do further study.