SSR Analysis Of Genetic Relationship In Ornamental Peach

In this study,22 ornamental peach cultivars were analyzed using SSR molecular markers method,19 cultivars among them were from Zhengzhou Fruit Research Institute, Chinese Academy of Agriculture Sciences, and the other 3 cultivars were from Beijing Academy of Agricultural and Forestry Sciences. This paper mainly discussed the DNA extraction method of ornamental peach, SSR-PCR system optimization, silver stain technique, SSR primers screening and genetic relationship analysis of these cultivars. The main results went as follows:(1) Construction of experimental technology systemAccording to the comparisons among several articles and the verifying of experiments, we finally chose the improved CTAB method (Liu Yan,2011) to extract the DNA in this study. A total volume 25 μl SSR-PCR reaction system including template DNA (20ng/μl) 3μl, primers (10μM)1.0μl, Mg2+(25 mM) 2.0μl, dNTPs (2.5 mM) 3.0μ1, TaqDNApolymerase (2.5 U/μl) 0.8μl,10×Buffer (free Mg2+) was determined by L25 (56) orthogonal design. Also the silver stain technique details were confirmed as follows:the gel glass was flushed by flowing water for 10 seconds, then it was put in 10% glacial acetic acid for 30 minutes with fixation purpose, following that it was flushed by flowing water for half seconds, subsequently put in 1% AgNO3for 20 minutes. With a quick rinse water again, it was finally put in the mixture of 1.5% NaOH and 0.25% methanol for coloration.(2) Screening of SSR primersWe screened 12 primerspairs with relatively high polymorphism of single loci amplification from the 41 SSR primers by E Dirlewanger (2002). Fourty-four bands in total weer amplified by the elected 12 primerspairs, the percentage of polymorphic lociwas 100% and the polymorphic bands amplified with each arbitrary pair of primer totaled 2-5,3.7 polymorphic bands were calculated for each.(3) Genetic relationship analysis of 22 ornamental peach cultivarsThe results of cluster analysis using NT SYS 2.10E software indicated that When the similarity coefficient was 0.66, all of the 22 ornamental peach cultivars were clustered into 3 groups according to the types of branches. Group I were consists of 10 P. persica vax.duplexs including the ’hongyebitao’,’baochun’,’sahong’, ’hongxiuqiu’,’dafen’,’chunyan’,’ersetao’,’jinchun’ and ’hechun’; 5 Dwarf type cutivars’shouhong’,’hongjuhua’,’juhuatao’,’manshanhong’ and ’mantianhong’ were classified in group Ⅱ;and group Ⅲ were consists of the other 7 P. persica var. pendula including ’danbanchuizhi’,’chuizhi-1’,’chuizhi-2’,’baichongbanchuizhi’, ’zhufenchuizhi-1’and ’zhufenchuizhi-2’.All of these results provided supports that it is reasonable to regard the type of branches as a higher classification level than the type of flowers. Meanwhile they indicated the existence of cross among the flower types, colors and leaf colors, and the lightest degree the cross exist among the flower types. The 22 ornamental peach cultivars selected in this study can be broadly categorized with type of branches and flowers as the first and the second classification standards respectively.