| Flowering cherries(members of Prunus subgenus Cerasus,Rosaceae) are the world-famous ornamental trees.There were disputes on the phyletic classification position and scope of Cerasus subgenus within the abroad schoolars. At present research, the flowering cherries was classified into Prunus subgenus Cerasus using the large genus system. More and more classification researchers indicated that Microcerasus did not belong to subgenus Cerasus. In recent years, more than 50 species of the Japanese cherry varieties were introducted and cultivated in our country. However, the cultivar classification system was still at the initial stage and it was easily resulted in cultivar identification difficulties and confusions on the application. There were a lot of controversies and doubts in identification and classification with the traditional classification features, like calyx tube,corolla and tree shape. A new identification and classification approach could be established by molecular techniques in support of cherry cultivar classification system. In this study,the genetic variation analysis and genetic relationship of the main oriental cherry cultivars in China were studied by using SSR molecular marker technology. The main results and conclusions are as follows:(1) In this study, 14 pairs of primers with clear bands, polymorphism and repeatability were selected. In addition to AM2939(2), DY6449(9), BPPCT005(15), BPPCT014(16),BPPCT034(19)and BPPCT041(22) 6 pairs of primers were moderately polymorphic, the others were highly polymorphic. Effective molecular marker primers in this study could be used as a genetic subgenus Cerasus species and germplasm resources diversity analysis.(2) The genetic diversity of 89 Cerasus accessions was evaluated by 14 pairs of SSR primers. Average effective number of alleles(Ne) was 4.409, Shannon's diversity index was1.493. Observed heterozygosity(HO) was 0.054-0.912, with an average of 0.498. Average expected heterozygosity(He) was 0.356-0.900,with an average of 0.650. The resultsshowed that the cultivated species had a relatively high level of genetic diversity. By means of Analysis of Molecular Variance, the results showed that 16% of the genetic variation occurred among populations, 84% of the variation occurred among populations.The genetic background of cherry blossoms was relatively single, there was no complicated lineage differentiation.(3) The genetic relationships of 89 species of cherry blossoms from 10 famous cherry blossoms in China were discussed. In addition to Shanghai, Gu Village Park ser Alr-SG3 and Xi'an Botanical Garden ser Kan-XZ6, Xi'an Jiaotong University sp11-XJ1 and Hangzhou Prince Bay Park ser Alp-HT1, Shanghai, Gu Village Park Kan Pra-SG10 and Shanghai Botanical Garden spe Yae-SZ16 phylogenetic relation- ships were closed, the phylogenetic relationships among the other varieties were distant.(4) In this study, the individual roughly could be divided into three different kinds of clones breeding group. Of the cultivars examined, 29 were of Type A, differing in both genotypically and morphologically, thus each of these 29 cultivars consisted of a singleclone. Twenty-one of the examined cultivars consisted of multiple clones, which have similar or near-identical morphologies but exhibit some genotype variation(Type B). In addition, there were 11 groups of two or more distinct cultivars with identical genotypes(Type C). In most cases, the members of a given group of Type C cultivars had identical morphologies, but some were clearly distinct. In type C, their morphological variations of Prunus serrulata‘Albo-rosea' and Prunus serrulata‘Grandiflora' mainly derive from bud sport mutations.(5) Based on the genetic distance NJ construction, this study has identified three species of unknown. Xi'an Qinglong temple in the individual SP4-XQ1 and SP4-XQ2 were the Prunus serrulata ‘Kanzan'. Shanghai Botanical Garden, a variety of Kan Ata-WX16 could be identified as the Prunus×Kanzakura‘Oh-kanzakura'. |
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