Identification of TP-M13-SSR molecular markers and genetic relationship analysis of seven new ornamental peach germplasms

  Objective  Genetic diversity and genetic relationship of the leaves from 15 commercially available common types and 7 new ornamental peach germplasms were studied and identified by simple sequence repeat (SSR). The purpose of this study was to explore the genetic distance between the new germplasm and commercially available common varieties, and to provide reference for the origin, evolution, development and utilization of ornamental peach and parental selection.

  Method  TP-M13-SSR PCR amplification and fluorescent capillary electrophoresis detection were carried out using 36 pairs of primers, and the amplification efficiency and polymorphism were analyzed. Genetic relationship of new ornamental peach germplasm ‘T13’, ‘T9-1’, ‘T10’, ‘T20’, ‘T22’ and ‘Zaohua’ was identified, and fingerprints of 22 ornamental peach germplasm resources were constructed using 6 SSR loci, and Neighbor-Joining clustering and comprehensive analysis combined with phenotypic traits was performed.

  Result  36 pairs of highly polymorphic primers were screened from 29 pairs of primers. A total of 183 polymorphic alleles and 98.396 effective alleles were detected. Average of observed heterozygosity was 0.341, and average of expected heterozygosity was 0.739. Average of Shannon’s information index was 1.546, and average of polymorphism information content of primer was 0.683, ranging from 0.510 to 0.841. The new germplasm ‘T20’ and ‘T10’ had the largest similarity coefficients with the existing variety ‘Taijie’, which were 0.95 and 0.92, respectively. ‘T20’ and ‘Taijie’ had the same phenotypic traits, including branch shape, petal color and petal type. The new germplasm ‘T13’ and the existing variety ‘Wubao tao’ had the highest similarity coefficient, which was 0.86. Similarity coefficient between the new germplasm ‘T22’ and other existing varieties was very small, and its phenotypic characters were quite different from the other 21 germplasms. Similarity coefficient of the new germplasm ‘T9-1’ and ‘Zaohua’ with the existing variety ‘Zhufen chuizhi’ was the largest, which was 0.94.

  Conclusion  In this study, through the construction of SSR fingerprint map, the ornamental peach germplasm resources can be identified more intuitively and quickly, providing technical and theoretical support for the later innovation of ornamental peach germplasm resources, the establishment of germplasm resource banks, and the protection and utilization of germplasm resources.