Construction Of Core Collections For Grape Germplasm Using SSR And SRAP Molecular Makers

The plentiful genetic resources of grape provide massive materials for geneticresearches and breeding work, but only small parts of which could be used effectivelyin the breeding practice. And huge resources quantities bring many difficulties for thegermplasm’s preservation, appraisal, research and utilization. In order to make moreeffective use of grape resources, this study employ M strategy (Core Finder and PowerCore), Genetic Distance method (least distance stepwise sampling, LDSS and geneticdistance optimization, GDOPT) and Core Hunter to construct grape core collectionsusing SSR and SRAP molecular marker on the basis of124grape primary corecollections built previously. The main results are as follows:1. Based on the optimized SSR and SRAP molecular marker system,9pairs ofSSR primers, the banding of which are unambiguous and stabled, were screened out. Atotal of184bands were amplified, the number of primers amplified bands ranged from14(VVMD7) to28(VRZAG79). Shannon index (I) ranged from0.44to0.58. Elevenpairs of primers were selected using SRAP, the expected heterozygosity (He) andShannon and Weaver diversity index (I) in the range of0.30-0.42and0.46-0.61. Theseindicate that the tested grape germplasms have a wealth of genetic diversity.2. Based on SSR molecular marker data, core germplasm groups established by Mstrategy, Genetic Distance method and Core Hunter separately were compared underdifferent sampling ratios. The result shows that the M strategy retains all of theprimary core collection of allele and the core germplasm extracted by genetic distancemethod is considered to be the most representative for original germplasm.Consequently, in order to build the core collection with the greatest genetic distanceand maximum genetic diversity, the core collections constructed by M strategy, geneticdistance method and Core Hunter law are merged into Core Set I, including48grapescore collections.3. Because SRAP data provide litter markers’ allele information, M strategy cannot be employed. Genetic distance method was used to extract core collection in10%、20%、30%、40%and50%of sampling ratios. The result of statistical testshows that the core collections have better representation in40%and50%, which isconsistent with SSR.4. The genetic diversity indexes and33phenotypic traits indicators of corecollections built by SSR, SRAP and SSR-SRAP data show that, the core collectionsCore Set I built by SSR are the dominant position in these core collection groups.5. TThrough genetic diversity index and phenotypic indicators of statistical testsand combining with the SRAP and SSR molecular markers of principal coordinatesanalysis, the results show that48grapes core collection retains96.21%primary corecollection of alleles with a minimum number of germplasms and represent92.90%original germplasm genetic diversity in5.53%sample proportion in Core Set I. Theseindicate that the core collection established in this study is valid. And the method usedin this study on construction of core collection also has important reference value forother crops.