Genetic Diversity Of Germplasm Resources On Wild Alfalfa (Medicago Sativa L.)

Alfalfa(Medicago sativa L.)is one of the most important member of the Geguminous genus Medicago.it is drought-resistant,hot and cold-resistant,high yield,good quality,could improve soil texture.So it is Cultivated and used widely,The main purpose is made into hay, silage or forage.Morphology,Genetic characteristics of photosynthetic and SRAP molecular marker technology are used in this research.Morphology,Genetic characteristics of photosynthetic and SRAP molecular marker technology are used in this research.Forty-two accessions of wild alfalfa are used as sample which came from thirteen courtries all over the world.The genetic diversity of alfalfa germplasm resources are analyed by phenotype,photosynthesis and DNA.The main results as follows:1.The alfalfa germplasm produces rich morphological diversity.Among the thirteen observed properties,morphological variances most significant in the mutation rate in the leaf area,and no significant variances occur in the features of plant morphology.The significant correlation was tested among morphological characters of alfalfa,the results showed a highly significant positive correlation between stem diameter and stem length,pubescence of germinal leaflet abaxial, pubescence of germinal leaflet adaxial and leaf area and 1000-seed weight,leaf width and leaf length.2.Principal Component Analysis show that the variances of phenotypic characteristics in different germplasm which came from forty-two accessions of wild alfalfa because of plant morphology,color,1000-seed weigh,leaf area and winter rate.Five main clusters generated by dendrogram with morphological characters revealed the difference of procreating growth.The cluster analysis suggested the high universality of distributing and ecological adaptability in alfalfa germplasm,too.3.The present study is the first report of ea evaluating the levels and patterns of genetic diversity among 42 collections of wild alfalfa by SRAP,a new molecular marker with few applications in forage and grass.Thirteen primer combinations were used and 273 bands were Produced in SRAP,of which 229(83.88%)were polymorphic.The percentage polymorphic band were higher than other species by SRAP marker.The coefficient range of genetic similarity was 0.498-0.882 with 0.686 on average,which showed rich genetic diversity of alfalfa germplasm,too.4.42 accessions could be divided into 5 main groups by cluster and principal component analysis,which could reveal the diversity from material more clearly. 5.After researching on the cluster analysis about phenotypic characteristics,SRAP molecular marker and the curves of diurnal course of photosynthesis,the result show that those materials can be divided into 5 groups by cluster analysis about phenotypic characteristics.The diurnal course of photosynthes of every material which came from each group is basically consistent,but number 115,number 122 and number 114 which came from group 2 and group 3 are different with the materials that came from the same group in the trend of diurnal dynamics.However,every material which came from each group are completely consistent by the cluster analysis about SRAP molecular marker in the diurnal course of photosynthes.So that phenotypic characteristics, molecular marker,photosynthetic characteristics are the same important in the research of genetic diversity about alfalfa.