【作者】 关潇；

【导师】 卢欣石；

【作者基本信息】 北京林业大学 ， 草业科学， 2009， 博士

【摘要】 苜蓿(Medicago sativa L.)是豆科苜蓿属,耐干旱、冷热,产量高且质优,能改良土壤,因而被广泛栽培利用,主要用制干草、青贮饲料或用作牧草。本研究采用形态学、光合遗传特性及SRAP分子标记技术,以世界15个国家的42份野生紫花苜蓿为材料,从表型、光合和DNA分子标记三个水平对野生紫花苜蓿种质资源的遗传多样性进行了分析,主要研究结果如下:1、野生紫花苜蓿具有丰富的表型性状多样性。在13个重要表型特征中叶面积的变异幅度最大,株丛形态的变异最小。各表型特征间相关分析说明主茎直径与主茎长度以及叶表面毛与叶背毛呈极显著正相关,叶面积与千粒重、叶宽、叶长都是极显著正相关。2、42份野生紫花苜蓿的主成分分析表明:不同种质之间表型性状间的主要变异来源于生长习性、花色、千粒重、叶面积以及越冬率这五个因子的影响。将供试材料分为5个类群的聚类结果显示了苜蓿生殖生长状况的差异。3、首次在国内运用技术较新且在牧草类作物应用非常少的SRAP标记对42份野生紫花苜蓿种质进行研究,用13对引物扩增,共扩增出273条带,其中多态性条带为229条,多态性比率83.88%,高于目前所报道的其他作物,每对引物组合平均21条的多态性条带。各材料间的GS值范围在0.498～0.882之间显示苜蓿种质资源间存在着非常丰富的遗传多样性。42份野生紫花苜蓿材料的聚类结果将所有材料划分为5类,典型特征是叶面积、千粒重、花色的不同,研究表明SRAP标记更能准确的反映材料的遗传多样性。4、研究了42份材料的净光合速率日变化曲线发现:按表型性状所分的五个类别中各材料的净光合速率的日变化趋势基本上是一致的,但115号、122号、114号这三份材料的变化趋势与组内其他材料表现出了不一致的趋势;但SRAP分子标记所分的五个类别中各材料净光合速率的日变化趋势在各自类别中是完全一致的,由此可见,光合特性也是研究遗传多样性的重要手段,光合特性和分子标记以及表型性状对于研究苜蓿的遗传多样性具有同等重要的地位。更多还原

【Abstract】 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.更多还原