关键词: 陇东野生紫花苜蓿, 过氧化物酶同工酶, 亲缘关系, 紫花苜蓿种质

Abstract: Longdong wild alfalfa(Medicago sativa L.cv.Longdong) is a rhizomatous perennial autotetraploid(2n=4x=32) legume forage found in the Longdong region of Gansu.It is considered to be Medicago sativa on the basis of its morphology,and has potential as forage because of its high branching ability,presence of rhizomes and its tolerance to trampling,cold and drought.but little is known about the genetic differences between Longdong wild alfalfa and cultivars.Peroxidase(POD) isozymes of Longdong wild alfalfa and other 38 alfalfa cultivars were analyzed using polyacrylamide gel electrophoresis.The genetic relationship among 39 cultivars was studied primarily based on cluster analysis and calculation of euclidean distance.The results showed that the POD isozymes zymograms of accessions had eleven isozyme bands which included four main ones,among which Longdong wild alfalfa had seven.39 alfalfa accessions were clustered into 6 groups using average linkage(between groups).Longdong wild alfalfa was clustered in an independent group.The Euclidean's distance between Longdong wild alfalfa and other tested materials varied from 0.748 to 1.622 with an average of 0.795 which were much more than between the cultivars which ranged from 0.533 to 1.029 with an average of 0.795,suggesting that the genetic distance between Longdong wild alfalfa and other 38 accessions was relatively wide.According to the genetic distance and cluster analysis,Longdong wild alfalfa can be regarded as distinct alfalfa germplasm,with the potential to broaden the genetic basis of cultivars developed by breeding programs.

Key words: Longdong wild alfalfa, Peroxidase isozymes, Genetic relationship, Alfalfa germplasm