Target Region Amplification Polymorphism (TRAP) for Assessing Genetic Diversity and Relationships Among Cultivated Populations of Dendrobium officinale

Abstract

Dendrobium officinale (Orchidacesae) is one of the rare and endangered species of herbs in China. Therefore, it will be beneficial to investigate the genetic diversity and relationships of cultivated populations of D. officinale for quality improvement. In this study, eight target region amplification polymorphism (TRAP) primer combinations were selected from fifty-four combinations, which were designed based on the related genes of the polysaccharides and alkaloids. A total of 148 fragments were scored in nine cultivated populations of D. officinale, including 130 (87.84%) polymorphic fragments. The analysis of genetic diversity revealed high level of genetic diversity in cultivated populations of D. officinale (H = 0.4125, I = 0.5985). Based on analysis of genetic structure, there was a moderate variation (Gst = 0.4706) and lower gene flow (Nm = 0.5625) among the cultivated populations due to some isolated measures, and domestication of excellent cultivars. Moreover, UPGMA dendrogram and Principal Coordinate Analysis (PCoA) indicated that nine cultivated populations were divided into four major groups. The results suggested that genetic relationships were associated with geographical germplasm sources instead of cultivation locations. Therefore, TRAP markers can be effectively employed to analyze genetic diversity and relationships among cultivated populations of D. officinale.