【作者】 高燕会；

【导师】 祝水金；

【作者基本信息】 浙江大学 ， 作物遗传育种， 2004， 博士

【摘要】 棉属有四个栽培种，其中亚洲棉（G.arboreum L）和草棉（herbacium L）为二倍体棉种、陆地棉（G.hirsutum L）和海岛棉（G.barbadense L）为异源四倍体棉种。棉花栽培种是棉花遗传育种最重要的种质资源，对于四个栽培棉种的种间杂交及其相关研究，不仅可提供丰富的中间优良育种材料，并可阐明棉花的遗传进化和遗传亲缘关系，对于棉花遗传改良具有重要的理论和实践意义。本研究以陆地棉、海岛棉、亚洲棉和草棉等四个棉属栽培种为材料进行种间杂交，对种间杂种及其亲本进行形态学、细胞遗传学、生理生化、荧光原位杂交和分子标记等研究，以明确四个栽培棉种及其种间杂种的遗传特点，进一步了解四个栽培棉种之间的亲缘关系和进化关系，为棉花种质资源的研究和利用提供科学依据。主要研究结果如下： 1．四个栽培棉种及其种问杂种F₁的形态学和细胞遗传学观察 四个栽培棉种的植株、叶片、茎杆以及花器等器官都有明显的差异；叶片、茎杆以及叶柄的横切面结构观察结果表明，两个二倍体栽培棉种的叶片横切面构造为等面叶，两个四倍体栽培棉种却均为背腹叶；（亚洲棉×草棉）F₁正反交的叶片也为等面叶，（陆地棉×海岛棉）F₁正反交F₁仍为背腹叶，而它们的四元杂交种均为等面叶；四个栽培棉种的叶柄和茎的横切面结构基本一致，只是直径形状和和维管束多少的不同，四元杂种的叶柄和茎的横切面结构的差异不明显。四个栽培棉种间杂交种F₁的细胞学观察结果表明，（亚洲棉×草棉）F₁减数分裂中期Ⅰ，形成一个环状四价体，直接证明了亚洲棉与草棉之间存在一对相互易位；（陆地棉×海岛棉）F₁减数分裂中期Ⅰ联会基本正常，主要形成二价体，偶尔出现一些单价体和多价体，以及染色体桥。两个二倍体棉种以及两个四倍体棉种间的杂种F₁植株生长和结实正常，但花粉半不育，说明亚洲棉和草棉之间以及陆地棉和海岛棉之间的亲缘关系很近，它们之间主要是由于染色体结构变异而形成生殖隔离，最后形成不同的物种。而四个栽培棉种相互杂交形成的四元杂种在减数分裂中期Ⅰ联会极不正常，其染色体构型为2n=52=5.14Ⅰ+14.69Ⅱ+2.46Ⅲ+1.50Ⅳ+0.70Ⅴ+0.15Ⅵ，减数分裂后出现大量的多分体，最终导致花粉不育，这是四元杂种F₁不育的细胞学原因，同时也说明四倍体栽培棉种的A染色体组与二倍体棉种的A染色体组并不是完全同源的，四倍体棉A染色体组的供体种仍需进一步研究。 2．四个栽培棉种及种间杂种染色体荧光原位杂交研究 通过对栽培棉种的rDNA-FISH结果进行分析，草棉的2对随体都是c型的，亚洲棉的随体为b，c型的，陆地棉为c，a，a型，而海岛棉的2对随体分别为ca型，可以推断草棉是最原始的棉种。此外，染色体核型分析结果表明，两个二倍体栽培棉种的染色体多为比较对称的In和S。类型，只是在染色体的长度上有差异，而两个四倍体栽培棉种的核型差异较大。四个栽培棉种的随体染色体数目和染色体类型的明显差异暗示了海岛棉和陆地棉在美洲有着不同的变异中心，四倍体棉种可能是多系统发育起源。 栽培棉种间杂种的体细胞和花粉母细胞的减数分裂染色体的gONA一FlsH的检测结果表明，两个二倍体棉种或两个四倍体棉种之间的杂种各染色体几乎均有亲本杂交信号，进一步证明它们之间的同源性。3.四个栽培棉种及种间杂种F;的生理生化分析四个栽培棉种及其种间杂种Fl的POD和SOD活性和同卫酶谱带进行结果表明，四个栽培棉种间的POD同工酶活性是有差异的，二元杂种 （亚洲棉X草棉）Fl的POO同工酶活性介于两亲本之间，（陆地棉x海岛棉）Fl的POD同工酶活性要高于两亲本，表现一定的优势。不同的四元杂种FI的POD同工酶活性也是不同的，其中以草棉为母本的四元杂种F，几乎检测不到PoD酶活。对POD同工酶谱的分析结果表明四个栽培棉种间的POD同工酶谱有一条很宽的相同条带，（亚洲棉X草棉）Fl有一条区分于亲本的POD同工酶谱带，（陆地棉x海岛棉）Fl的POD同工酶谱带和母本的POD同工酶谱带相同的较多。不同组合的四元杂种F，的POD同工酶是不同的，其中有3个组合兼有四个亲本的特征谱带，l个组合没有POD同工酶谱带，为特殊的资源材料。 栽培棉种间的SOD活性也不同，二倍体棉种的SOD活性基本相同，但四倍体棉种间的SOD活性相差较大，且种内不同品种的SOD酶活也有较大的差异。栽培棉种间二元杂种的SOD酶活性均介于两个亲本之间;四元杂种SOD酶活性同样也是介于四个亲本之间的。栽培棉种及其杂交种SOD同工酶谱分析结果表明，各个栽培棉种间的SOD同工酶差别不大，亚洲棉、草棉、陆地棉和海岛棉各有3、3、5、5条SOD同工酶谱带，其区别只是条带亮度的不同。栽培棉种间杂交种F，的同工酶存在着一定的差别，其中（亚洲棉X草棉）Fl的SOD同工酶谱带较其亲本的条带细而淡，并缺失双亲的另一条酶带;陆地棉和海岛棉杂交种SOD同工酶谱带与亲本相似，但酶谱带亮度不同。四个四元杂种组合的SOD同工酶谱带较弱。因此，SOD同工酶谱带很难鉴别物种之间的差异。4.四个栽培棉种及种间杂种杂种F:SSR分子标记多态性分析以四个栽培棉种及其种间杂种Fl为研究材料，进行ssR分子标记多态性分析。结果?更多还原

【Abstract】 Cotton (Gossypium sps) being the world’s major fiber crop, it has been growing in more than 80 countries. It has four cultivated species namely G. arborewn, G. herbarium which are diploids and G. hirsutum, G. barbadense which are allotetraploids. These species have been the important source of the germplasm for cotton inheritance and breeding programmes, and these species are valuable in the cotton genetic improvement research. Studies on the interspecific crossing among the four species and their relationships not only provides enough intermediate quality materials, but also explains their genetics, evolution and phylogenetic relationships, which will be significant for the theory and practice. The characteristics of the karyotype, chromosomes, the relationships and evolution among the four species and their hybrids (F1) were studied by using the morphology, cytogenetics, physiological-biochemical characteristics, fluorescent in-situ hybridization (FISH) and molecular markers and so on. Results of all these studies are as follows and they would provide the scientific evidence for the resources of the cotton germplasm. 1. Study on the morphology and cytogenetics among the four cultivated cotton speciesand their hybrids (F1).The characteristics of the plants, leaves, stems and floral tissues between the four cultivated cottons were found to be significantly different. The leaves of the G. arborewn and G. herbarium were isobilateral leaves, and those of G.hirsutum and G. barbadense were dorsiventral leaves. The reciprocal F] of cross G. arborewn x G. herbarium were also isobilateral leaves, while reciprocal F1 cross of G.hirsutum x G. barbadense were also dorsiventral leaves. The quadrispecific hybrids F1 were isobilateral leaves, regardless of their cytoplasms. The structures of the leaf stalks and the stems were analogous to each other among the four cultivated cotton species except their diameters varied with species.The cytogenetics of interspecific hybrids (F1) among the four cultivated cotton species were studied in this paper and results are as follows: The diploid interspecific hybrid (G arborewn XG. herbarium) F1had a four-chromosome-ring at the meiotic metakinesis. The synapses of tetraploid hybrid (G. hirsutum x G. barbadense) F1 was found to be regular, which mainly formed bivalents, sometimes some univalents, multivalents and chromosome bridge. The diploid interspecific hybrid and the tetraploid hybrid grown and fruited regularly, but the pollen were semisterile. All these showed that the relationship was close between G. arborewn, G herbarium, and between the G. hirsutum and G. barbadense. The meiosis of the quadrispecific hybrid (F1) was abnormal, The chromosome configurationof the quadrispecific hybrid (F,) 2n=52=5.141+14.69 II+2.46 III+1.50 IV+0.70V+0.15VI. There were lots of multiad at the anaphase, which resulted pollen sterility which were the reason for sterility of the quadrispecific hybrid F1. These showed that the A-sub-genome of the tetraploid cultivated cotton species were homologous incompletely with the diploid A genome of the cultivated cotton species. The donor of A-sub-genome for tetraploid cultivated cottons were still studied on.2. Study on the FISH of the four cultivated cotton species and their hybrids.We concluded the results from the analysis of the rDNA-FISH for the four cultivated cotton species: 2 pairs of satellites of G herbarium were ’c’, those of G. arboreum were ’b’ and ’c’, G.hirsutum were ’c’, ’a’, ’a’ , G barbadense were ’c’ and ’a’. So we could infer that G herbarium was the original cotton species and the donor species of A-sub-genome of two allotetraploids. In addition, the results of the karyotype showed that chromosomes of G. arboreum and G herbarium were symmetrical, except that the chromosome length was different. Different numbers and types of satellites of G.hirsutum and G barbadense showed that G.hirsutum and G barbadense had different center of variation. The developmental origin of the tetraploid cultivated cotton species could be更多还原