【作者】 高伟；

【导师】 王坤波；

【作者基本信息】 华中农业大学 ， 作物遗传育种， 2010， 硕士

【摘要】 棉属包括5个四倍体棉种,其中陆地棉和海岛棉为栽培种,达尔文棉、黄褐棉和毛棉为野生种。从种质资源角度来讲,陆地棉野生种系也属于四倍体野生棉,它是未经栽培驯化的陆地棉原始类型,不仅具有抗病虫,耐干旱、耐盐碱、纤维高强优质等遗传特性,而且比野生资源更容易导入栽培品种,所以对于改进棉花品质和抗性都具有很好的利用价值。本研究利用形态学标记和SSR标记对18份四倍体棉种及42份陆地棉野生种系材料的遗传多样性进行了综合分析,以期进一步验证前人所得的棉花种属关系结果；并了解野生种系及材料间的多样性水平及其遗传关系。其意义在于为今后有效利用陆地棉野生种系材料提供理论依据,为育种家提供更广泛的种质资源,从而促进棉花种质资源的收集、保存以及有效利用。研究主要结果如下：1.对陆地棉野生种系进行了形态学性状观察,结果发现尖斑棉和阔叶棉多数材料的花柱高度较低,阔叶棉的株高在7个种系中最低；莫利尔棉和玛利加郎特棉多为晚熟材料,但后者多数材料含花瓣基斑。鸡脚叶或超鸡脚叶是帕默尔棉最明显的特征。2.对野生种系17个形态及农艺性状的统计分析表明,不同材料之间存在较大差异,不同性状在不同材料间表现出了不同程度的多样性,尤以主茎茸毛、叶片形状、花瓣基斑大小以及铃数的变异系数较大,均大于50.00%,而以株高的变异系数为最小,仅为21.10%。3.多样性指数分析显示,13个质量性状的平均多样性指数为0.992,而4个数量性状的平均多样性为1.972,总体平均多样性程度较高,不同性状之间的多样性指数差异较大。各种系内部多样性指数均明显低于总体,以莫利尔棉种系质量性状的多样性指数为最低(0.435)。4.形态学数据聚类分析显示,所有野生种系材料之间的遗传距离在0.602-2.127之间变化,平均为1.387。42份材料中的28份均准确聚到如下四个分支：尖斑棉(Ⅰ),玛利加郎特棉(Ⅱ),莫利尔棉(Ⅲ),阔叶棉(Ⅳ),而其他3个种系均因材料数目较少无法单独聚成一类,散布在其他种系中。5.95对SSR引物在60份四倍体材料中共检测出658个等位基因位点,其中多态性位点580个,占88.15%；引物等位位点数的变化范围为2-14个,平均每对引物6.93个；对于陆地棉野生种系而言,95对引物中有90对SSR引物能在42份材料间扩增出多态性条带,共检测出530个等位基因位点,包括多态性位点438个,占82.64%；引物等位位点数2-12个,平均每对引物5.89个。6.多态信息含量(PIC)、基因多样性(H’)和有效等位基因数(Ne)在四倍体棉种间和陆地棉野生种系内的变化幅度均较大,表明SSR标记可以反映较丰富的遗传多样性信息,但陆地棉野生种系多样性程度低于四倍体棉种间多样性。7.60份材料的成对相似系数范围为0.157-1.000；对于42份陆地棉野生种系材料来说,成对相似系数范围缩小为0.306-1.000,平均相似系数为0.493,将所有相似系数分10个区间统计,在0-0.700区间内的系数占总数的92.56%,表明陆地棉野生种系的遗传相似性很低,从反面也就说明其遗传多样性非常丰富。8.基于SSR标记的UPGMA聚类分析表明：陆地棉与陆地棉野生种系中阔叶棉的亲缘关系最近。海岛棉与达尔文棉的亲缘关系非常相近。黄褐棉与毛棉相对较近。陆地棉与其他四个棉种的亲缘关系最远。更多还原

【Abstract】 There are five tetraploid cotton species including 2 cultivated species, G.hirsutum and G.barbadense, and 3 wild species, G. darwinii watt, G. mustelinum Miers ex Watt and G. tomentosum. From the perspective of germplasm resources, G.hisutum L.races also belong to the tetraploid wild species. They are primitive types of the Gossypium hirsutum without cultivation and domestication, which not only has unique hereditary property of disease or insect resistance, drought or salt tolerance, high sthength and quality fiber but also easier to transfer good gene into cultivated species than wild resouces. So there was good value for utitilization to improve fiber quality and resistance. In order to verify the results of relationship among cotton species reported in previous studies and discover the diversity level of races and its genetic relationship, the genetic diversity of 18 allotetraploid cotton species and 42 upland cotton races were assessed based on agronomic and SSR analysis. Its significance lies in providing theoretical basis for effective utilization of races in future and offering more germplasm for breeders, thereby promoting the collection, conservation and effective utilization of cotton germplasm resources.The main results are as follows:1. Morphological observation of races revealed:The stylus height of the most Punctatum and Latifolium were low, but the plant height of the Latifolium was the lowest. Most of the Morrlli and Marie-galante were late-maturing, but there were petal base spots in most of the Marie-galante. Chicken foot-shaped and Super chicken foot-shaped were the clearest characteristic of Palmeri.2. Statistical analysis based on 17 morphological and phenological characters of races revealed:There were obvious differences in various materials, and different traits of different materials have expressed some degree of diversity, especially the coefficient of variations (CV) of Stem solfandthick, Leaf shape, Petal base spot size and Boll number were larger than 50.00%, but the CV of plant height was the smallest, only 21.10%. 3. The results of diversity indices indicated that the average diversity indice of 13 qualitative trait was 0.992, which among 4 quantitative trait was 1.972. So the whole diversity was relatively high, but the diversity indexes of different traits varied in larger interval. The diversity indices of each race were distinctly lower than general, the diversity indice of qualitative trait was the smallest in Morrlli, only 0.435.4. The cluster results based on morphological data showed that the genetic distance of all races was among 0.602-2.127 with an average of 1.387.28 cotton germplasms among 42 cotton germplasms mentioned above that were classified into 4 branches exactly:Punctatum(Ⅰ),Marie-galante(Ⅱ), Morrlli(Ⅲ),and Latifolium(Ⅳ). However, other 3 races could not be clusted branches respectively because of small amount of materials, which were clustered in other races.5.95 pairs of primers used in 60 different germplasm accessions, and a total of 658 DNA fragments were scored, of which 580 polymorphic bands were obtained, accounting for 88.15% of the total bands; The range of allele (NA) per SSR locus were 2 to 14 with the average of 6.93; Similarly, with 90 primers among 95 primers produced polymorphisms in all materials, we could detecte 530 DNA fragments in 42 upland cotton races, of which 438 polymorphic bands(82.64%) were obtained; The range of allele (NA) per SSR locus were 2 to 12 with the average of 5.89.6. The variation limit of polymorphism information content(PIC), Shannon-weaver diversity index(H’) and Effective number of alleles(Ne) varied widely, indicating a wide genetic variation among 60 tetraploid cotton species and 42 upland cotton races by SSR markers, but diversity among the five tetraploid cotton species were more abundant than races.7. The genetic similarity (GS) coefficient in 60 germplasms ranged from 0.157 to 1.000, the minimum of which in 42 races reduced to 0.306 and with the average of 0.493. Count the numbers of the coefficient in 10 interval distribution, the percentage was 92.56% in the range of 0-0.700, which displayed that genetic similarity were very low in upland cotton races, in other words, the genetic diversity of upland races were so abundant.8. UPGMA cluster analysis based on SSR showed that the genetic relationship is the nearest between upland cotton and G. hirsutum race.Latifolium, Gossypium barbadense and G. darwinii watt is very close, G.mustelinum Miers ex Watt and G.tomentosum L.Nuttall ex Seeman is a bit close, It’s the farthest between upland cotton and others.更多还原