[Study on the relationships of Cymbidium by RMAPD technique].

Cymbidium is one of the Orchidaceae genera. There are 70 Cymbidium species in the world, mainly distributed over the tropical and the subtropical area of Asia and northern Australia. In China, approximately 49 species and some variations are distributed over the provinces to the south of Qinling. The orchid market of China is quite wide, not only because of their view and admiration value, but also their officinal value as well. Some species of Cymbidium are morphologically similar, so the identification of Cymbidium species and the understanding of the relationships between them are very important for new varieties breeding of Cymbidium. This study attempts to apply RMAPD to detect the relationships between the Cymbidium species. 456 pairs of RMAPD combinations were screened, but only 12 pairs of them were used to analyze the genetic polymorphism of 16 Cymbidium. 362 bands were produced by 12 pairs of RMAPD primers in total, including 90 polymorphic bands (24.8%). The polymorphic bands of each primer combination ranged from 3 to 11 with the average of 8. Among all species, genetic similarity coefficient ranged from 0.63 to 0.87. The result showed that the genetic distance was closest between C. floribundum and C. aestivum, C. ensifolium and C. sinense, C. maguanense and C. hookerianum, which is almost the same as the traditional classification. It was the first time that species of Cymbidium were detected by RMAPD technique. This study shows RMAPD is an appropriate and effective molecular marker technique to identify the relationships of Cymbidium.