Studies On The Genetic Diversity Of The Registered Alfalfa Varieties (Medicago L.) In China

The genetic diversity , relationship between the 31 registered alfalfa varieties and an unregistered alfalfa variety in China were studied using the markers of seed storage proteins(SSPs) and peroxidase allozyme. The results show that as following:Monomer weights of alfalfa seed storage proteins in the 32 varieties are from 21.2Kd to 85.1kD.Bands polymorphism of SSPs appear mainly in 43.7kD to 25.7kD and 74.1kD to 66.lkD.The coefficient of gene differentiation (Gsri)of the 18 local varieties is 0.168 and that(GsT2) of the 14 bred ones is 0.162,indicating that the genetic variation mainly exist within varieties(the local varieties,83.2%;the bred ones,83.8%).The average gene diversity within the bred varieties (Hs2=0-3136) is lower somewhat than within the local ones(Hs1=0.3310),which shows that the heterozygosities of the local varieties is higher than that of the bred ones. It is closely related to the reproductive method of alfalfa seeds, the cultivating pattern and the resources of the parents breeding the bred varieties. The local varieties are divided seven groups with the index of λ1=3.854,and the relationship between local alfalfa varieties is mostly related to ecogeographic distribution. Given the index of λ2=3.700,the bred varieties are divided six groups which are decided by the parents of the 14 varieties. When the total 32 varieties are divided by λ3=4.015,there have nine groups which correlate to their ecogeographic distribution and their parents.The results of alfalfa peroxidase allozyme display that the coefficient of gene differentiation is 0.062,and the genetic variation of the total varieties exist mostly within varieties(93.8%) instead of among varieties(6.2%).