木薯‘新选048’自交系群体表型鉴定评价及遗传多样性分析

Phenotypic identification and genetic diversity of cassava cultivar ‘Xinxuan 048’ inbred lines

为了研究木薯‘新选048’自交系群体的遗传差异,本研究通过变异系数、遗传多样性指数、多态性比例、遗传相似系数、聚类分析等方面对‘新选048’的83个自交系株系进行表型鉴定及遗传多样性分析。结果表明,自交系株系各性状的变异系数处于9.94%~157.74%之间,数量性状的变异系数低于质量性状,叶长最低,茎分叉习性最高;遗传多样性指数处于0.07~1.91之间,数量性状的遗传多样性指数高于质量性状,叶尖形状和顶端叶颜色最低,最大薯长最高。块根中氢氰酸(HCN)、淀粉和可溶性总糖含量均发生分离。与亲本相比,各株系的淀粉含量均低,可溶性总糖含量均高,且分离出低HCN株系。相关性分析表明,极显著相关的性状有26对,显著相关的性状有16对。24个表型性状共提取了9个主成分, 21个性状起主要作用。利用SSR分子标记进行遗传多样性分析, 18对引物共扩增出78条条带,多态性比例达89.74%,各株系间遗传相似系数介于0.40~0.90之间。对比表型聚类和分子标记聚类结果,发现二者具有一定的关联性,但不完全相同,聚类结果并无明显规律。本研究通过自交系鉴定出一批木薯中间材料,丰富了我国木薯种质资源的遗传多样性,并为木薯自交系育种提供参考。

In order to study the genetic differences of cassava ‘Xinxuan 048’ inbred lines, the phenotypic identification and genetic diversity analysis of 83 ‘Xinxuan 048’ inbred lines were carried out through variation coefficient, genetic diversity index, polymorphism ratio, genetic similarity coefficient and cluster analysis. The results showed that, variation coefficient of all relevant traits of the inbred lines ranged from 9.94% to 157.74%, the leaf length was the lowest, the stem fork habit was the highest, and variation coefficient of quantitative characters was lower than that of qualitative characters. The genetic diversity index was between 0.07 and 1.91, the genetic diversity index of quantitative characters was higher than that of qualitative characters. The genetic diversity index of the top leaf color and the tip shape was the lowest, the genetic diversity of the maximum tuber length was the largest. The phenotype value of hydrocyanic acid(HCN), starch and total soluble sugar content in the tuber of the population presented wide segregation. Compared with the original parent, starch content decreased, total soluble sugar content increased, and lines with low HCN content appeared. The correlation analysis showed that there were 26 pairs of highly significant correlated traits and 16 pairs of significantly correlated traits. Nine principal components were extracted from 24 phenotypic traits, and 21 traits played a key role. Totally, 78 bands were amplified by 18 pairs of primers, and the polymorphism ratio was 89.74%. The genetic similarity coefficients between the lines ranged from 0.40 to 0.90. By comparing the results of phenotypic clustering and molecular marker clustering, it was found that there was a certain correlation between them, but they were not identical. Meanwhile, there was no obvious rule in clustering results. In this study, a number of cassava intermediate materials were identified through inbred line, which enriched the genetic diversity of cassava germplasm resources in China and provided reference for cassava inbred line breeding.