Analysis Among 40 Cultivars Of Cymbidium Longibracteatum Using AFLP Marker

The genetic diversity and relative relations of 40 cultivars of Cymbidium longibracteatum were studied by using amplified fragment length polymorphism(AFLP) makers.The main results were as follows:1.AFLP reaction system suitable to Cymbidium longibracteatum had been optimizeded through experiment.The results of AFLP analysis was clear,reliable,easy to repeat and high stabilization.2.12 AFLP primers combinations were used in AFLP analysis.These primers combinations generated 515 bands,of which 242 bands were polymorphic.The rate of polymorphic bands was 45.45%and the average polymorphic bands was 42.92 per primer combinations.The bands mainly distributed among 200 bp and 1200bp.3.The clustering result of 40 cultivars of Cymbidium longibracteatum showed that the samples were clustered by colors besides minority of red cultivars.The genetic similarity of 40 cultivars among 0.7858 and 0.9563 and the average genetic similarity was 0.8837.This indicated that the genetic variability of Cymbidium longibracteatum was not high.4.The analysis of genetic similarity based on the same colors indicated that:the genetic variability and genetic diversity within colorful-spots cultivars was higher than others for the average genetic similarity of colorful-spots cultivars was 0.9012,the lowest and the genetic similarity range of colorful-spots cultivars was 0.8667～0.9563,the widest.The analysis of genetic similarity based on different colors indicated that:the relative relations between green cultivars and red cultivars was further for their genetic similarity was the lowest(0.8840),the relative relations between red cultivars and colorful-spots cultivars and that between red cultivars and colorful-spots cultivars were closer for their genetic similarity were higher.5.The analysis of genetic similarity and clustering both indicated non-significant gene differentiation,low genetic similarity and low genetic diversity of Cymbidium longibracteatum.There seemed no apparent differences between samples that from different areas.The Cymbidium longibracteatum samples used in this study were all from man-made environment.The low genetic variability of samples was due to the same growing conditions,pollinate conditions and purposely controlling.This was beneficial for keeping ornamental characters and high purity of Cymbidium longibracteatum.