| Peach [Prunus persica (L.) Batsch] was originated in China, along with the several thousands years of cultivation and genetic improvement, there are plentiful of genetic resources and ecological types as well as divergent cultivars in China. The research on genetic relationships of cultivars and molecular evolution of peach will be much helpful to genetic improvement of peach. The phylogenetic relationship of peach and nectarine cultivars was analyzed in this study through the use of SSR markers and ITS sequence.The genetic relationships of 95 peach and nectarine cultivars and three kindred species, P. ferganensis Kost. et Riab, P. davidiana Franch and P. mume Sieb. et Zucc, which originated from China, Japan, the USA and South Korea, were evaluated using 33 simple sequence sepeat markers (SSRs) screened among 108 SSR markers obtained from published SSR markers developed in peach or sweet cherry. 33 SSRs detected polymorphisms among 96 peach and nectarine cultivars and revealed total 283 alleles with an average of 8.6 alleles per locus. The polymorphism information content (PIC) value ranged from 0.40 (BPPCT041) to 0.98 (BPPCT009), with an average of 0.80.Most peaches and nectarines were classified according to their geographical origins except some Chinese cultivars. The 96 peach and nectarine cultivars were classified into 6 groups, "Chinese Northern and Northwestern local cultivars", "Chinese southern local and Japanese & American cultivars", "P. ferganensis and Renmiantao", "Chinese dwarf cultivars", 'Fenshouxing' and 'Baishanbitao', respectively, by the cluster analysis based on Nei's genetic distances:Group I, "Chinese Northern and northwestern local cultivars" was consisted of Chinese northern and northwestern local cultivars, and was divided into two subgroups: Chinese local white peach and yellow peaches;Group II, "Chinese southern local and Japanese & American cultivars" was consisted of around 67 % of all cultivars investigated and was divided into four subgroups: Japanese white peach cultivars, Chinese flat peach cultivars, the American yellow cultivars and some of Chinese local ornamental peach cultivars.Group III, IV and V were "P. ferganensis and Renmiantao", "Chinese dwarf cultivars" and 'Fenshouxing' were comprised of Chinese local ancient cultivars.Group VI had only 'Baishanbitao'.Based on the clustering results, northern china local flat peaches were closer to northern white cultivars in genetics, while Chinese southern flat peach and Japanese white peach cultivar had a close genetic relationship. 'Baishanbitao' had been proven an ornamental cultivar as its long distance fromother cultivars in terms of genetic distance. On the whole, the genetic background among Chinese local peach cultivars accounted for much more distribution than those genetic background ranges of the cultivars of Japan, the USA and South Korea, which further proves the P. persica is native to China.Nucleotide sequences of the ITS (internal transcribed spacer) regions were determined for 52 peach cultivars (P. persica L. Batsch) from China, Japan, America and Korea, compared with three related species, P. ferganensis, P. davidiana and P. mume. The ITS regions of 52 peach cultivars, from 624 bp to 629 bp, did not show much of differences. ITS 1 region was 229-232 bp, 5.8s rDNA gene was 85 bp, and ITS 2 is 278-281 bp. 5.8s rDNA genes did not have diversity among cultivars (2 sites), ITS 1 and ITS 2 regions had 21 sites and 20 sites, respectively.Based on the phylogenetic analysis, 52 peach cultivars and two related species (P. ferganensis, P. davidiana) tested in this study were divided into 4 branchs:Branch â… , "Baishanbitao and American yellow peaches", contained all yellow peaches except 1 Chinese local yellow one, 2 Chinese ornamental cultivars and 6 Chinese white peaches.Branch â…¡, Japanese yellow peach mutation, Janghowenhwangdo obtained in Korea.Branch â…¢, "Japanese white peaches", had mainly all Japanese white peach cultivars with a bigger difference of genetic distance than that of the other 3 branchs.Branch â…£, "P. david...
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