Development Of Simple Sequence Repeat (SSR) Markers From Paeonia Ostii And Its Unilization In Genetic Relationship Analysis

The tree peony belongs to section Moutan of Paeonia, known as the ’King of Flowers’in China and has great ornamental, medicinal and economic value. With the development of peony breeding and cultivation globally, many issues related to interspecific genetic relationships, origin of cultivated varieties and molecular-assisted selection (MAS) in breeding programs rely heavily upon documentation using reliable and efficient molecular markers. Here, P. ostii T. Hong&J. X. Zhang was involved in this study using magnetic beads enrichment method to characterize simple sequence repeat (SSR) markers and their ability to cross-amplify in herbaceous peony. Moreover, we tested the validity of the SSR markers in studying the genetic relationships among tree peonies. The main results were as follows:1. Constructing enrichment libraries of the peony. Two hundred and thirty-seven positive clones were selected and sequenced. Ninety-one contained SSRs, in which115microsatellite loci were identified and79were designed primers.36of which eventually showed the expected band. Of the36primer pairs,24were monomorphic and12were polymorphic. Transferability test showed that most of the SSR markers could be used in related spesies.2. Application of12polymorphic SSR markers in studying genetic relationships among48tree peony species and cultivars. A total of42alleles were generated across48tree peony accessions, the polymorphism information content varied from0.257to0.794, with an average of0.468. Shannon Index was ranged from0.594to1.771and the mean value was0.906, which means the markers developed are in high genetic diversity. Cluster analysis demonstrated that P. rockii was the main ancestor of the Xibei cultivars, P. rockii and its cultivars were closely related to P. decomposita,P. ostii contributed significant genetic information to Zhongyuan cultivars, Zhongyuan cultivars and P.×lemoinei hybrids also have some relationships between each other. Principal component analysis (PCA) based on gene frequency further illustrated these genetic relationships. PCA supported the results of the clustering analysis, and it is easily discernable that cultivars from the same group distributed together, while wild accessions with a close relationship to cultivars were distributed with the cultivars.