【作者】 崔永霞；

【导师】 张名昌； 白建荣； 张效梅；

【作者基本信息】 山西大学 ， 作物遗传育种， 2012， 硕士

【摘要】 种质遗传基础狭窄是我国玉米育种的主要限制因素。在玉米地方品种蕴涵有优良基因,是玉米育种的宝贵资源。山西省地理位置特殊,大面积为山区,南北差异和垂直差异较大,它是华北平原区向西部山地、黄淮海温带作物区向高寒作物区的过渡区域,地形复杂。不同的玉米品种经过长期的驯化,形成了适应不同的生态环境的遗传丰富的玉米农家品种,是不可多得的种质资源。分析和利用山西玉米地方种质资源的遗传多样性,对扩大玉米种质基础具有重要作用。以DNA为基础的SSR分子标记技术具有许多优点诸如：操作简单,多态性高,大部分标记为共显性,对生物体的影响表现为中性,和不良性状无必然连锁,不受时间和空间的限制等优点。因此在遗传多样性分析等方面得到广泛应用。本文采用混合取样方法和SSR分子标记技术,利用均匀覆盖在玉米10条染色体上的48对引物对38个地方品种DNA样品进行PCR扩增,分析山西省38个玉米地方品种的遗传多样性及其之间的遗传关系。研究结果如下：148对引物在38个地方品种中共扩增出368个等位基因,每个SSR位点的等位基因数为2-16个,平均为7.67个；平均多态性信息量为0.76,变化范围0.24-0.89之间,第12号引物检测到等位基因数最多为16个。检测出稀有等位基因185个,占全部等位基因的50.3%；特有等位变异21个,占全部等位基因的5.7%。2几乎在所有的地方品种上检测到的等位基因数都在40个以上，如23号材料沁源白土玉米,20号材料屯留小玉茭上48对生物总共检测出的等位基因数分别为50和59个,说明这几个材料的遗传变异比较丰富。值得注意的是祁县的农家种玉米遗传多样性更加丰富,每个材料通过48对引物检测出的等何基因数都在41个以上祁县的小头白玉米和六十日及小白玉米都分别检测出47个等位基因;祁县的白马牙白洋玉米,软白玉米检测出的等位基因数分别为42,43,41个338个玉米地方品种之间的遗传相似系数在0.87到0.53之间。其中,青县小白玉米与大宁县白马牙的遗传相似系数最高为0.87,表明这两个地方品种的遗传距离较近,种质遗传基础差异比较小。沁源白马牙和和顺白玉米的遗传相似系数最小为0.53,表明这两个地方品种的遗传距离最远,种质遗传基础差异大。4根据遗传相似数矩阵,按照UPGMA进行聚类分析,得到152个混合样本SSR分析聚类图。再由152个混合样本的遗传相似系数矩阵计算出38个品种之间成对品种的平均遗传相似系数矩阵,得到38个品种的树状聚类图。更多还原

【Abstract】 The narrow germplasm base is the main factor limiting the success of corn breeding programs in China. In some regions, the local corn varieties may contain some desirable genetic features, and thus being considered as valuable germplasm resources for corn breeding. Due to the special geographical location of Shanxi Province, there is a large hilly area with a wide geographical diversity and significantly dispersed vertical height. In between the North China Plains and West China Plateau, Shanxi is the transitional region at where the predominant commercial crop changes from the Temperate Zone crops to the Frigid Zone crops. The terrains in Shanxi are complex. After a long-term cultivation, various corn varieties have developed into ecologically adaptive local corn varieties with diverse genetic variability, which are considered as rare germplasm resources. Therefore, the study and analysis on genetic diversity local germplasm resource in Shanxi play an important role in broadening the corn germplasm base. The SSR molecular marker technique based on DNA has many remarkable features, such as easy operation, higher polymorphism, co-dominant nature for most markers, moderate effect on the organism, no inevitable linkage between poor alleles, temporally and spatially independent and etc. Therefore, it is widely applied in various research fields, such as genetic diversity analysis and etc. In this study, both composite sampling approach and SSR molecular marker technique were employed to perform PCR gene amplification for38DNA samples of local varieties, based on48pairs of primes that homogeneously overlying10chromosomes in corn cell, and thus investigating the genetic diversities and correlations among the38local corn varieties in Shanxi. The results were as follow:1. By using the48primers, a total of368alleles have been detected due to the gene amplification done for the38local varieties. The number of alleles at each SSR locus ranged from2-16, with a mean of7.67; the average polymorphic information content was0.76, varying from0.24-0.89. The number of alleles detected by12#primer was16, which was the highest. A total of185rare alleles was detected, proportional to50.3%of the total allele number; the number of specific alleles was21, accounting for5.7%of total alleles.2.The local corn varieties from Qixian County had the most abundant genetic diversity, as at least41alleles have been detected by the48primers in each of the samples from the county. Specifically,47alleles were detected in "Qixian Small-head white corn","Qixian Sixty-day corn" and "Qixian Small White corn" respectively;42alleles were detected in "Qixian Baimaya Corn";43alleles were detected in "Qixian Baiyang Corn" and "Qixian Soft White Corn";41alleles were detected in "Qixian Baitu Corn".3. The coefficients of genetic similarity among the38local corn varieties ranged from0.87to0.53. In particular, both "Small White corn" from Jixian County and "Baimaya Corn" from Daning County had the highest coefficient of genetic similarity, which was0.87, indicating that a small genetic disparity between corn varieties in these two counties and a relatively less differed genetic base for germplasm. In contrast, both "Baimaya Corn" from Qinyuan County and "White Corn" from Heshun County had the lowest coefficient of genetic similarity, which was0.53, indicating that a large genetic disparity between corn varieties in these two counties and a relatively more differed genetic base for germplasm.4. By employing genetic similarity matrix, in combination with UPGMA cluster analysis, The SSR analytic clustering configuration of152hybrid samples was shown in Figure3.5. Through calculation based on matrix of genetic similarity coefficients among the152hybrid samples, the matrix of average genetic similarity coefficients for the38local varieties was obtained, and the clustering dendrogram of the38local varieties was shown in Figure3.6. By comparison, Figure3.6appeared to be a miniature version of Figure3.5.更多还原