Microsatellite DNA in peach (<i>Prunus persica</i> L. Batsch) and its use in fingerprinting and testing the genetic origin of cultivars

We isolated and sequenced 26 microsatellites from two genomic libraries of peach cultivar ‘Redhaven’, enriched\nfor AC/GT and AG/CT repeats, respectively. For 17 of these microsatellites, it was possible to demonstrate\nMendelian inheritance. Microsatellite polymorphism was assayed in 50 peach and nectarine cultivars. Of the 1300\nPCRs carried out, all but two produced amplified products of the expected size. All microsatellites were polymorphic,\nshowing 2–8 alleles per locus. Heterozygosity ranged from 0.04–0.74 (mean 0.47); the discrimination power (PD)\nranged from 0.04–0.84 (mean 0.60). Cultivar heterozygosity varied greatly, with one cultivar (‘Independence’) being\nhomozygous at all loci. The set of microsatellites discriminated all cultivars investigated, except several sport mutations,\ni.e., ‘Dixitime’ vs. ‘Springcrest’, ‘Compact Redhaven’ vs. ‘Redhaven’, and two pairs of cultivars, ‘Venus’ vs.\n‘Orion’ and ‘Elegant Lady’ vs. ‘Rome Star’, whose pedigrees are controversial. We were able to analyze the paternity\nof several cultivars. In most cases, the parenthood was confirmed. The comparison of three long-living ‘Redhaven’ accessions\nsupplied by different repositories did not provide any evidence of somatic instability of microsatellites. Hence,\nmicrosatellites, ranked according to their information content, are recommended as markers of choice for peach fingerprinting and suggestions are provided for interpreting band profiles and the correct sizing of alleles.