Multi-copy SSR Markers And Its Utilization For Analysis Of Genetic Diversity In Phyllostachys Edulis

The Phyllostachys edulis stand cover amount of areas ranged widely. During the longtime silviculture, several variations with stable phenotype divergence were selected and different provenances are different from each other in physiological, biochemical and morphosis level. Some molecular markers have been used in estimating the genetic diversity of P. edulis. In this study, genetic diversity of the cultivars, provences and seedlings were estimated systematically using SSR markers.During the development of SSR markers for P. edulis, we found that some pairs of SSR primers may amplify multi-locus SSR. We successfully developed 13 multi-locus SSR markers. To estimate the efficiency of multi-locus SSR, we picked up this 13 pairs of multi-locus primers(1 of GSS-SSR and 12 of EST-SSRs, which can amplify 28 SSR loci in all) and 28 single-copy SSR primers to detect the genetic diversity of 25 P. edulis seedlings (group M1), respectively. Eight loci produced by multi-copy SSR primers presented polymorphism, but seven from single-copy SSR primers. The ratio of locus with polymorphism number to primer number is 25.0% (single-copy,7/28) and 61.5% (multi-copy,8/12) respectively, the value of multi-copy primers is 2.46 times of single-copy. This indicates that multi-copy SSR markers are more efficient for estimation of genetic diversity in P. edulisTo detect the genetic diversity of cultivars, provenances and seedlings more effieciently, we make use of 38 pairs of single-copy and 5 pairs of multi-copy SSR primers from P. edulis, which can amplify 49 loci, to examine the genetic diversity of two bamboo stands each with 25 seedlings, 18 different ages of seedlings,17 provenances and 10 cultivars. Firstly, there is genetic diversity among the seeds from the clums flowering simultaneously at the same bamboo stand, the ratio of polymorphic loci is 24.5% and 14.3%. And the gene types of clums from different bamboo stands are different. Secondly,30.6% polymorphic loci exist among the 18 different ages of seedlings, and the variance may mainly caused by genetic diversity inheriting from their parents. Thirdly,19 loci (38.8%) with polymorphism are found among 17 provenances. Differences among 17 provenances don't respond to their living places, combining the result hereinbefore, we assume that the accumulation of random mutation and the genetic diversity in each provenance is the basement of the establishment of genetic divergence. Lastly, no differences are found among all cultivars, maybe the SSR loci used are not enough, or the results of some other mechanism such as epigenetical reason.Through the genetic diversity research of these four types of P. edulis sample, we found that many genetic differences may exsit longtime ago. The barely difference exists among cultivars, and then we can study the mechanism causing phenotype divergence among cultivars from DNA methyletion and transponson. To know the genetic structure is helpful to the germ plasm conservation and associate the breeding, which is also meaningful to the planting and management of P. edulis stand.