Analysis of molecular genetic diversity in Alfalfa(Medicago sativa L.)germplasm is of great importance for conserving and breeding programs.The objective of this study Wag to evaluate the genetic diversity of alfalfa varieties.and to identify them through screening the variety-specific primers.This report analyzed the genetic diversity of 16 alfalfa varieties from Gansu Province based on RAPD markers using bulking equal quantities of DNA from 20 individuals of a cultivar.Based on the Roger's distances between the sixteen cultivars,the dendrogram by UPCMA cluster analysis showed that the relationships among these cultivars were tightly related to breeding programs.There was a clear difference between creeping variety Jindera and other erect varieties.Within the erect accessions.3 distinct groups including one introduced varieties and synthetic varieties originated from alien germplasm.one east-central group and one west group,were detected.Four of 10 primers,OPE4,OPE5,OPE6 and OPE7.amplified the specific bands belong to 5 cultivars,Gannong 3,Ganza 27,Jindera,Longdong and Algoniun,were detected,respectively,which could be used to identify alfalfa varieties throngh exploring the variety-specific primers.

Alfalfa (Medicago sativa L.) belongs to the typical allogamy,and the sampling strategies are closely related to its molecular genetic diversity analysis. Four alfalfa varieties,Longdong (local variety), Zhonglan 1 (synthetic variety),Graze and Queen (introduced variety),were selected and their bulked DNA samples obtained from 10,20,40 and 60 individual plants,respectively. The results of unweighted pair-group method with arithmetic averages (UPGMA)analysis based on random amplification polymorphic DNA (RAPD)and simple sequence repeat (SSR)markers showed that 40 and 60 bulked DNA sample methods had the same genetic relationships between these 4 alfalfa varieties, which indicated that populations with 10 and 20 individual plants were too small,and the accurate analysis were positive related to the sampling numbers but the cost of analysis increased also. According to the results above,40 individual plants was the suitable sampling strategies in genetic diversity analysis of alfalfa based on RAPD and SSR markers.

Alfalfa(Medicago sativa L.) is a forage legume of world-wide importance and the genetic relationship and distance among cultivars are of great interest for breeding programs.In this paper,random amplified polymorphic DNA(RAPD) was used to analyze the genetic diversity of 11 alfalfa cultivars.A total of 132 discernible loci were obtained for all populations using 10 primers,and 81.1% of these loci were polymorphic,which indicated a high genetic diversity in the cultivars from Gansu Province.According to the Roger's distance,the smallest MRD(0.1406) occurred between cultivars 'Tianshui' and 'Longzhong',while the largest(0.4610) was detected between cultivars 'Tianshui' and 'Dingxi'.The result of AMOVA analysis showed that the majority(61.25%) of genetic variation was within populations and 38.75% among populations.