The Assessment Of Genetic Diversity And Genetic Relationship For Pears Native To The Middle Area Of Gansu Province Using SSR And AFLP Markers

The Gansu local pears originnated in the middle of Gansu province including the areas of Lanzhou,Linxia,Lintao.Those pears are valuable and precious,which have great applied value in the industry of pears,but the genetic diversity and genetic relationship among these local pears was unknown so far, which limite the use of these resource. So diversity and genetic relationship of 47 accessions of pear germplasm native to the middle area of Gansu Province in China were analyzed using simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP)markers, which displayde the diversity and genetic relationship of these pears in the below:At first, genetic diversity and genetic relationship of 46 accessions of pear germplasm native to the middle area of Gansu Province in China were analyzed using simple sequence repeat (SSR) marker with 6 pairs of SSR primers. The range of heterozygosity was between 0.446 and 0.738 with an average of 0.639; and the range of Shannon information index was between 0.897 and 1.489 with an average of 1.217. Based on the UPGMA cluster analysis, 46 pear accessions could be obviously divided into 7 major groups, of which 7 groups were generally consistent with morphological classification: P. xerophila Yu, P. pyrifolia Nakai var. sinensis Y. Teng et K. Tanabe (Chinese white pears), P. ussuriensis Maxim, P. phaeocarpa Rehd. and P. communis L, and the other two groups were composed of unknown types showing some more affinities to P. ussuriensis.'Huanghuali'belonging to P. pyrifolia was grouped with Chinese white pears. Five accessions of P. sinkiangensisYu were not clustered together into the same group, but scattered to groups of P. xerophila, Chinese white pear and P. ussuriensis, respectively. Some accessions that couldn't be classified according to morphology were clustered with P. xerophila, Chinese white pear or P. communis, which displayed genetic relationship among those pear accessions. Though P. xerophila accessions were sampled in the narrow region, they also showed the abundant genetic diversity.In the second place genetic diversity and genetic relationship of 40 accessions of pear germplasm native to the middle area of Gansu Province in China were also analyzed using amplified fragment length polymorphism (AFLP)marker with 6 pairs of AFLP primers. The total number of 472 bands were amplified with which the polymorphic bands were 404,the rate of polymorphic is 86%. Based on the UPGMA cluster analysis, 40 pear accessions could be obviously divided into 7 major groups by the coefficient of 0.72 in the map of clustering, of which 7 groups were generally consistent with morphological classification: P. xerophila Yu, P. pyrifolia Nakai var. sinensis Y. Teng et K. Tanabe (Chinese white pears),P. communis L,P. sinkiangensis Yu,P. phaeocarpa Rehd and two other P. ussuriensis Maxim which contained unknown types of pears that showing some more affinities to P. ussuriensis.Those results showed not only abundant the genetic relationship but also genetic diversity among the pear accessions in the middle of Gansu Province.In the whole, SSR and AFLP are two effective molecule markers to indentified the pears from the middle areas of Gansu province,which displayed the genetic diversity and genetic relationship among them.