控制海岛棉零式果枝类型的基因发掘与功能鉴定

The sea-island cotton （G. barbadense L.）is one of the most important cultured varieties in the world, has many merits such as having long，fine and strong fiber，and it is the important raw material of high-grade for special spinning cotton textiles. Southern xinjiang is one of China's important production regions of sea island cotton. Zero-fruit branch plant type, as a basic plant type, has good characteristics , including excellent fertility and early-maturing, and has been used today. The trait plays an important role in the sea island cotton breeding and cultivation. A large number of cotton high-density molecular genetic maps have been constructed and SSR markers have been explored and utilized. The sequence of Gossypium Raimondii has been completed in 2012. These researches have provided a molecular foundation for related gene location and biological character molecular identification. In present project, the cross of 9122И×hai 3-79 is to be made, which includes one parent with zero fruit branch type, the other parent, hai 3-79, with Ⅲ-type fruit branch. High polymorphism, good stability of SSR primers are be employed to screen the polymorphism between two different fruit branch type sea-island cotton cultivars and to construct a genetic linkage map of sea-island cotton. Based on composite interval mapping to mine and map genes of zero fruit branch type and using genetically modified (GM) methods to clarify related genes regulating zero fruit branch type of the sea-island cotton, this study is to determine candidate genes and provide theoretical basis for sea-island cotton（G. barbadense L.）breeding programs.

海岛棉是世界重要的棉花栽培种之一，具有纤维长、细、强等优点，是纺制高档和特种棉纺织品的重要原料。南疆是中国重要的海岛棉生产基地，零式果枝株型为基本株型，具有丰产早熟优质的特性，一直沿用至今，在海岛棉育种和栽培生产中发挥了重要的作用。大量棉花高密度分子遗传图谱的构建和SSR标记的开发利用，2012年雷蒙德氏棉的成功测序，为相关生物学性状的基因定位和鉴定提供分子基础。本项目以海岛棉零式果枝品系9122И和长果枝海岛棉遗传标准系3-79作亲本配制杂交组合，利用多态性高、稳定性好的SSR标记构建海岛棉种内遗传连锁图谱，应用复合区间作图法对控制零式果枝的基因进行定位，结合棉花测序数据挖掘基因，并通过转基因手段以期对相应基因进一步进行功能鉴定，从而明确相关基因在调控海岛棉零式果枝形成中的生物学功能，为海岛棉的株型育种提供候选基因及理论依据。

海岛棉是世界重要的棉花栽培种之一，具有纤维长、细、强等优点。南疆是中国重要的海岛棉生产基地，零式果枝株型为基本株型，具有丰产早熟优质的特性，一直沿用至今。本项目以海岛棉9122И（零式果枝）和H7124（长果枝）杂交，种植亲本及杂交F2代进行果枝类型鉴定和数量性状分析，同时提取基因组DNA，建库测序与棉花基因组测序数据比对，对零式果枝基因进行定位并筛选候选基因，结果如下：.1、筛选出具有多态性的SSR引物213对。.2、F1代无论正交反交均为长果枝,零式果枝相对于长果枝而言为隐性性状，受细胞核基因控制，与细胞质基因无关。.3、F2代中发现除了双亲的果枝类型即零式、长果枝类型之外，出现第三种类型即叶腋处零式果枝和长果枝混生的现象；调查F2代9642株，其中零式、长果枝和混生分别为2838、3501和3303，零式果枝占1/3.4；零式果枝性状不是由单个基因控制，可能由多个基因或主效、修饰基因控制。.4、对F2三种果枝类型中分别收获300个单株进行经济性状分布及相关研究不同果枝类型棉株存在显著或极显著差异，零式果枝产量、品质性状表现最差；3种果枝类型产量性状相关性趋势一致，籽棉重与铃数、单铃重间呈极显著正相关，铃数与铃重间呈负相关关系，衣分与其他产量性状相关性不显著；零式果枝中纤维品质5个指标之间呈显著或极显著的正相关，且与单铃重间呈显著或极显著正相关；而另两种果枝中，除马克隆值以外，长度、整齐度、强度和伸长率间呈显著或极显著的正相关，但与衣分间均呈负相关；混合果枝类型是南疆海岛棉育种的理想株型。.5、估计6个亲本各性状的配合力效应值和遗传参数，3-79的品质性状GCA最高，泗棉 3号和新陆早3号衣分和单铃重具有正向的高GCA值。3-79×新陆早3号为最佳组合。叶片茸毛与棉酚腺体数的HN2和HB2均＞60%，而叶片SPAD与干重均则＜50%。.6、测定并比较35个海岛棉品种叶绿素含量、SPAD值，结果品种间有显著差异，SPAD值与叶绿素含量各指标间存在显著或极显著正相关，35个海岛棉品种依据叶绿素含量、SPAD值分为5类。.7、经过基因组DNA测序，零式果枝基因定位在D07染色体9052280-18595524的区间，有5个候选基因，其中“Gh_D07G1075”与张天真团队研究并发表的序列一样。.