Abstract: 【Objective】 A total of 131 apple germplasms including landraces, bred cultivars and related species selected from the National Repository of Pear and Apple Germplasm Resources in Xingcheng, China were studied with tailed primer M13 microsatellite markers (TP-M13-SSR). An analysis was made to establish the molecular ID of 131 apple germplasms.【Method】Based on genetic fingerprints, germplasms were distinguished with selected SSR markers, alleles that were amplified by each marker were coded, then was combined as a molecular ID.【Result】Two accessions selected from a total of 131 accessions were used for optimization of the first PCR detecting conditions and SSR primer screening. 16 pairs of TP-M13-SSR primers with high stability and good repeatability were used to establish the fingerprints of 131 accessions of Malus Mill.. By using 16 selected SSR markers, 326 polymorphic sites were detected with a mean value of 20.3. The amplification of CH05d04 for all germplasms obtained 49 alleles with the highest expected heterozygosity 0.878, and the amplification of CH01f07a for all germplasms obtained 48 alleles. The polymorphism information content was calculated by PopGen32 with 0.7558 on average. 16 SSR markers could distinguish 11 accessions at least, 71 accessions at most, and 49 accessions on average. The identified rate was 8.09%-52.21%. The identified rate of CH01f07a was the highest, and the identified rate of BGT23b was the lowest. Based on the PIC of amplification and identified rate, each parir of two SSR primers was combined together to identify all the accessions. The combination of CH04h02 and CH01f07a could distinguish 120 accessions at most. More SSR primers were combined together. Finally three SSR primers could distinguish all the accessions. All the alleles of the three core SSR markers were sequenced from small to large, and the assignment was from number 01. A character string was constituted by combining all the codes of the three primers for every accession. By using barcode technology molecular ID can be transferred into a barcode ID that can be quickly scanned by machine.【Conclusion】Based on the PIC of amplification and identified rate, core SSR primers can be screened out to distinguish all the landraces, bred cultivars, and related species. And by constructing fingerprints, every apple germplasm obtains its differentiable molecular ID that can be recognized by the machine. The purpose was to distinguish the most apple germplasms by using the least and the most specific primers.

Key words: apple(Malus Mill.), germplasm resources, TP-M13-SSR, molecular ID