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

摘要： 利用聚丙烯酰胺垂直板凝胶电泳技术对陇东野生紫花苜蓿(Medicago sativa L. cv. Longdong)及其他38个紫花苜蓿品种的过氧化物酶(POD)同工酶酶谱特征进行分析,通过对供试材料间欧氏距离的计算和聚类分析,初步探讨了39个紫花苜蓿材料间的亲缘关系.结果表明:供试材料共表现出11条酶带,且都具有4条主酶带,其中陇东野生紫花苜蓿表现出条酶带;用组间均连法进行聚类分析,39个供试材料可聚为6类,其中陇东野生紫花苜蓿单独为一类,且与其他38个供试材料间的欧氏距离介于0.48～1.622,平均值(1.088)远远高于其他供试材料间的平均欧氏距离(0.533～1.029),表明它们之间的遗传距离相对较大.由此可确定陇东野生紫花苜蓿与其他供试材料间的亲缘关系较远,为一相对独立的紫花苜蓿种质资源,可通过育种途径扩大栽培品种的遗传基础.

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