基于表型的棉花种质资源遗传多样性分析及核心种质的抽提

Analysis of Genetic Diversity of Cotton Germplasm Resources and Extraction of Core Germplasm Based on Phenotypic Traits

种质资源是遗传育种研究的基础,分析种质资源的遗传多样性,可为亲本选配提供一定的理论依据。通过对500份棉花种质资源材料的11个表型性状,进行遗传多样性、相关性、主成分和聚类分析,结果表明,11个性状的平均变异系数为9.69%,有6个性状的变异系数超过了10.0%,其中结铃数的变异系数最大为20.14%,纤维整齐度的变异系数最小为1.81%;各性状的遗传多样性指数为1.71~2.06,结铃数的遗传多样性指数最高,生育期的遗传多样性指数最低;相关性分析表明,各性状间存在着不同的相互关联,纤维长度与纤维整齐度、断裂比强度、生育期呈极显著正相关,与马克隆值极显著负相关,断裂比强度与马克隆值、生育期呈极显著正相关,衣分与纤维长度、纤维整齐度、马克隆值呈极显著正相关,与子指呈极显著负相关,铃质量与衣分、纤维长度、纤维整齐度、生育期呈极显著正相关;主成分分析提取到了5个主成分,累积贡献率为73.677%,第1主成分与纤维长度、断裂比强度、纤维整齐度有关,第2主成分主要和衣分有关,第3主成分主要与马克隆值有关,第4主成分主要与果枝数有关,第5主成分主要与铃质量有关;聚类分析将500份棉花种质材料在遗传距离1.33处分成了4大类,第Ⅰ类群包含1份材料,属于株高高、铃质量大、衣分低、子指高的材料;第Ⅱ类群包含73份材料,属于结铃数少,衣分偏低,纤维品质较差的棉花材料,第Ⅲ类群包含122份棉花材料,属于铃质量、衣分、纤维长度、纤维强度最好的棉花材料,第Ⅳ类群包含304份棉花材料,属于铃数、铃质量、衣分、纤维长度、纤维强度适中的棉花材料;提取了50份棉花资源材料构建了核心种质库,核心种质库与原始群体相比各性状的变异系数、方差更高,表明核心种质具有更好的异质性,更大的变异。核心种质库用最少的资源数目保留了种质资源的遗传信息,不仅减少了种质保存的工作量,也更有利于育种亲本的选配。

Germplasm resources are the basis of genetic breeding research.Analyzing the genetic diversity of germplasm resources can provide a certain theoretical basis for parental selection.Genetic diversity,correlation,principal component and cluster analysis were performed on 11 phenotypic traits of 500 cotton germplasm resources materials.The results showed that the average coefficient of variation of the 11 traits was 9.69%.And there were 6 trait which coefficient exceeded 10.0%.The variation coefficient of the number of bells(20.14%)was maximum,and the variation coefficient of the fiber uniformity(1.81%)was minimum.The genetic diversity index of each trait was in the range of 1.71-2.06.The genetic diversity of boll number was highest and the genetic diversity index of growth period was lowest.Correlation analysis showed that there were different correlations between the various traits.Fiber length was significantly positively correlated with fiber uniformity,fiber strength and growth period but it was significantly negatively correlated with the micronaire value.The fiber strength was significantly positively correlated with the micronaire value and growth period.The lint percent was significantly positively correlated with the fiber length,fiber uniformity,and micronaire value but significantly negatively correlated with the seed index.The boll weight was significant positive correlated with lint percent,fiber length,fiber uniformity and growth period.By the principal component analysis,5 principal components were extracted which cumulative contribution rate was 73.677%.The first principal component mainly related to fiber length,fiber strength,and fiber uniformity;the second was mainly related to the lint percent;the third was mainly related to the micronaire value;the fourth was mainly related to the number of fruit branches and the fifth was mainly related to the boll weight.Cluster analysis classified 500 cotton germplasm materials into four clusters at genetic distance 1.33.ClusterⅠcontained only one material,which character was high plant height,high boll weight,low lint percent,high seed index.ClusterⅡcontained 73 materials,which characters were few boll,low lint percent,and poor fiber quality.The ClusterⅢcontained 122 materials,which characters were high boll weight,high lint percent,long fiber and high fiber strength.ClusterⅣcontained 304 materials,which boll number,boll weight,lint percent,fiber length,and fiber strength were moderate.50 germplasm resources were extracted to construct the core collection.The variable coefficient and variance of each trait in core collection were higher than ones in the original population.Indicating that the core germplasm has better heterogeneity.The core collection heterogeneity was better than the original population.The core collection retains the genetic information of germplasm resources with the least number of resources,which not only reduces the workload of germplasm conservation,but also facilitates the selection of breeding parents.