Construction of a high-density genetic map and QTLs mapping with GBS from the interspecific F1 population of P. ostii 'Fengdan Bai' and P. suffruticosa 'Xin Riyuejin'

Tree peony (Paeonia suffruticosa Andrews.) is an important ornamental and medicinal plant in China. However, the genetic mechanisms controlling the traits of interest have not been extensively investigated. In this study, an F1 hybrid population, derived from the cross of P. ostti ('Feng Dan') as the female parent and P. suffruticosa ('Xin Riyuejin') as the male parent, was used to construct the genetic linkage map using genotyping-by-sequencing (GBS) technique. From the high-throughput sequencing, a total of 243.35 Gb raw data were generated. And then 257,335,738 high-quality GBS markers were detected. Finally, an integrated genetic map containing 3868 markers was constructed, which distributed on 5 linkage groups (LGs). The genetic linkage map spanned 13175.5 cM with an average distance of 3.406 cM between adjacent markers. Based on this map, QTL analysis was performed. A total of 6 QTLs for 4 phenotypic traits of flower number, petal length, petal number and flowering stage were detected. This high-density genetic linkage map and QTL mapping for important flower related traits using GBS with an F1 population of tree peony in this study will provide a solid foundation for gene positional cloning and molecular marker-assisted breeding in the near future.