我国陆地棉基础种质表型性状的遗传多样性分析

Genetic Diversity of Basal Germplasm Phenotypes in Upland Cotton in China

选用43份陆地棉基础种质为研究材料,随机区组排列种植,并进行果枝数、铃数、株高等田间性状调查和衣分、铃重、纤维品质等测定.按照不同时期、不同来源、不同生态区对这些基础种质分别进行表型性状的遗传多样性分析.结果表明:基础种质间在产量、品质、农艺性状等表型性状上差异显著或极显著,遗传多样性指数为0.88;3期基础种质大部分性状差异不显著,但第2、3期基础种质比第1期的纤维长、整齐度高、细度好、衣分增加、早熟性提高、抗病和耐旱性增强,第2期基础种质遗传多样性和遗传丰富度最高;来自不同棉区的基础种质表型性状差异较大,黄河流域棉区基础种质综合性状较好,长江流域棉区产量性状较高,北部特早熟棉区早熟性好,美国引进种质抗黄萎病性较强;国内基础种质比国外品种在纤维长、强、细上的变异系数均有不同程度降低,但国内基础种质表型多样性比引进品种高.以上研究说明引进品种经过长期的环境适应、自然选择和人工选育后,产生了表型变异较为丰富的基础种质类型.

43 basal germplasms were chosen as the experimental subjects and they were planted in randomized block manner; the numbers of their fruiting shoots, bolls and plant heights were investigated in the field and their lint percentage to seed cotton, boll weights and fiber qualities were measured. Besides, the genetic diversity in their phenotypic traits was analyzed in terms of their time histories, sources and ecological zones. It was shown that these basal germplasms significantly or extremely significantly differed in such phenotypic traits as yield,quality and agronomic traits and their genetic diversity index was 0.88;the basal germplasm newly developed or derived in 1970s and 1980s did not significantly differ in a majority of their traits,but the basal germplasms screened from the varieties extended at home and abroad in 1950s and 1960s and the varieties newly developed or derived in 1970s and 1980s were better in fiber length,uniformity and fineness and lint percentage to seed cotton, early maturity, disease resistance and drought tolerance than the eleven varieties introduced from such countries as the United State and former Soviet Union,and the highest genetic diversity and abundance appeared in the basal germplasms screened from the varieties extended at home and abroad in 1950s and 1960s;the basal germplasms from different cotton production zones greatly differed in their phenotypic traits,the basal germplasms from the cotton production regions covered by the reaches of Yellow River showing a overall set of advantageous traits,the basal germplams from the cotton production regions covered by the reaches of Yangtze River performing better in their yield traits,the basal germplasms from the cotton production regions of extremely early maturity in north China performing well in their early maturities,and the basal germplasms introduced from the United States having good resistance to verticillium wilt; domestic basal germplams were lower in the CVs of their fiber length,strength and fineness than introduced foreign basal germplasms,but the former were more diverse in their phenotypes than the latter. These above indicated that after their long environmental adaptations the introduced varieties produced basal germplasms with rich phenotype variations due to natural and artificial selections.