Analysis of the Germplasm Resources and Genetic Relationships among Cymbidium tortisepalum Cultivars Using Amplified Fragment Length Polymorphism Markers

Cymbidium tortisepalum, a Chinese orchid, originated from the basin of Sanjiang, Northwest Yunnan province. This study reports the genetic relationships among 84 cultivars of Cymbidium tortisepalum by amplified fragment length polymorphism (AFLP) markers, including 16 cultivars with plain flowers, 22 cultivars with butterfly-petal-shaped flowers, 19 cultivars with lotus-petal-shaped flowers, 10 cultivars with plum-petal-shaped flowers, and 17 cultivars with poly lips' or poly petals' flowers. Nine AFLP primer combinations produced a total of 1614 fragments with an average of 179 fragments per primer pair, of which 1411 bands were polymorphic. Based on the amplification results, fifty-five of the tested cultivars had a total of 117 specific bands. Unweighted pair group method based on arithmetic average (UPGMA) analysis was performed on dice's similarity coefficient matrix and also average similarity of each cultivar. The dice coefficients among the tested cultivars ranged from 0.1045 to 0.7750, with an average value of 0.4097. The tested 84 cultivars of C. tortisepalum were grouped into four clusters with the similarity coefficient of 0.35. The first cluster consisted of 14 cultivars with plain flowers, 22 cultivars with butterfly-petal-shaped flowers, 15 cultivars with lotus-petal-shaped flowers, and 5 cultivars with plum-petal-shaped flowers. The second cluster included other 2 cultivars with plain flowers. The third cluster contained 17 cultivars with poly lips' or poly petals' flowers, 5 cultivars with plum-petal-shaped flowers, and 3 cultivars with lotus-petal-shaped flowers. The fourth cluster comprised one cultivar with lotus-petal-shaped flowers. These results revealed that the genetic relationships among tested cultivars of C. tortisepalum were related to their flower types' classification.