Sampling Strategy for a Primary Core Collection of Peach (Proous perslca (L) Batsch.) Germplasm

摘要

Sampling strategies were evaluated to select for a primary core collection of peach (Primus persica (L.) Bat-sch.) that would be the representative of the base collection of peach cultivars at the Beijing's National Peach Germplasm Resources Repository. The optimal sampling strategy was established based on the coverage of morphological and agronomic characters in 18 taxonomie groups. In order to determine the most representative core collection, we used a simulation approach to identify the optimalsampling scheme. Nine entire sampling ratios from 10 % to 90 % were tested. The sampling scheme was conducted at two levels, first to divide the collection into biologically relevant groups and then to determine the appropriate core selections within groups. The results indicated that 10 % was the appropriate entire sampling ratio from the base collection. The optimal sampling scheme was to divide all the accessions into different variety groups, and then determine the sampling proportion within groupsbased on its genetic diversity (G) using a random sampling method. Using this sampling strategy, a primary core collection with 56 accessions was selected from a base collection of 558 accessions of different peach cultivars. The primary core collectionrepresented 99.49 % of the ratio of phenotype retained (RPR) of the base collection, and its index of genetic diversity (I) was 0.63, which was significantly higher than 0.59 of the base collection. The evaluation results indicated that the primary corecollection was able to represent the initial germplasm collection in genetic diversity and heterogeneity.