Genetic Diversity And Utilization Potential Analysis Of Alfalfa(Medicago Sativa L.)Germplasms Of Xinjiang

Alfalfa(Medicago sativa)is the most important leguminous forage all of the world,it has heigh production,good palatability and heigh protein content.So it has great value of research and production exploitation potential.XINJIANG is the region where distributed more alfalfa germplasm resources of China.Study of alfalfa germplasm resources in XINJIANG could discover more alfalfa genetic variation of China,and it's useful for pick out the better alfalfa germplasm resources that could be used in breeding.It could also guide the alfalfa germplasm resources' genetic diversity protection of Xinjiang and ensure the resource's sustainable use.Combined phenotype,stress resistance and DNA molecule technological means,20 alfalfa germplasm resources' main morphological characteristic,major agronomic traits,winter hardiness(including fall dormance and wintering rate),primary nutrients,salt resistance,drought resistance,and ISSR?RAPD?SSR 3 kinds of molecular markers had been studied in this paper.The results are as follows:1.The difference of fall domancy characters of alfalfa that came from northern Xinjiang and southern Xinjiang was very big.All germplasm resources collected from northern Xinjiang were fall dormancy type,most of their fall dormancy level was 1,one germplasm resources' fall dormancy level was 3.Semi-domancy germplasm resources had not been found from northern Xinjiang.But,there were fall dormancy type and semi-domancy types in southern Xinjiang area.Germplasm resources of 1,2,3 dormancy level were existed in fall dormancy types,and 4 to 5 dormancy level germplasm resources had been detected in the semi-domancy types in southern Xinjiang.2.Morphological variation between the alfalfa populations of Xinjiang were significant,among which variation of leaf area was the biggest,it changed from 0.83cm2 to 3.10cm2,germplasm ChangJi had the biggest leaf area.Next was the variation of natural height,it changed from 36.20cm to 110.30cm.Germplasm AerTai2 had the biggest seed production(2221.11kg/hm2),and its variation was the biggest in major agronomic traits.Germplasm KuerL had the biggest total hay production(38459.22kg/hm2).The wintering rate of germplasm HaBHe reached 98.53%.All of germplasm HaBHe?ChangJi?TaChen?XinY2?FuHai?KuerL?HeT?MinFl had bigger height,higher hay and seed production,quicker regrowth speed,higher winter percentage,better comprehensive agronomic characters and with excellent production performance,could be used in alfalfa breeding and production priority.3.Germplasm HaBHe had higher crude protein content(21.28%),higher amino content(17.15%)and lower crude fiber content(26.32%),could be used priority in quality breeding of alfalfa.4.The regression analysis of stress concentration versus relative germination indicated the simulation results of cubic polynomial model was more close to reality.The difference of salt resistance and drought resistance among tested germplasms were very significant.Lethal concentration of NaCl salt ranged from 0.129%to 1.114%.Lethal concentration of PEG-6000 ranged from4.751bar to 13.704bar.5.All of the three kinds of molecular markers(ISSR?RAPD?SSR)research showed the genetic diversity of XINJIANG alfalfa was abundant.There was high genetic differentiation among the tested alfalfa populations.But,the sequencing of genetic diversity of different alfalfa germplasms of XINJIANG was differ.The correlation of genetic relationship between ISSR,RAPD and SSR were not significant.6.Comprehensive comparative of the research results of morphological characteristics,agronomic traits,nutritive value,winter hardiness,drought resistance,salt tolerance,and genetic diversity of 20 alfalfa germplasm resources showed that germplasm HaBHe had better morphological indexes,relatively taller plants,higher grass yield and seed yield,faster regeneration speed after cutting,higher rate of overwintering,good production performance.It also had higher crude protein and amino acid content,lower crude fiber content,and good drought resistance and salt tolerance at seed germination stage.SSR and ISSR molecular markers identified it's genetic diversity were in the middle level among the tested germplasms.RAPD molecular marker identified it had low genetic diversity,which fully reflected the uniformity of the comprehensive characteristics.So,germplasm HaBHe had great potential for breeding,production and utilization,which could be used as hybrid parents or directly to breed new alfalfa varieties.