甜椒核心种质资源比较构建研究

构建核心种质可大幅提高种质资源利用效率。以410份甜椒种质资源为材料,基于8个性状表型数据,采用混合线性模型分析方法无偏地预测基因型值,利用马氏距离计算种质间遗传距离,分别采用两种聚类方法(最短距离法和类平均法)和两种取样方法(随机取样法和偏离度取样法),按照25%抽样比率构建甜椒核心种质库。采用均值、方差、极差和变异系数4个指标评价不同取样和聚类构建核心种质库水平。结果表明,最短距离法能极显著增加性状方差和变异系数,明显优于类平均法;偏离度取样法优于随机取样法;基于马氏距离、最短距离法和偏离度取样方法获取的102份甜椒核心种质资源能代表原群体遗传多样性。该研究可为甜椒种质资源有利基因发掘和新品种选育奠定基础。

Comparative study on the construction of sweet pepper core collection

Core collection construction could greatly improve the utilization efficiency of genetic resources. Taking 410 sweet pepper germplasm as tested materials, genotypic values of eight traits were unbiasedly predicted by using linear mixed model analysis method. Genetic distances among accessions were calculated using Mahalanobis distance based on genotypic values. The core collections of sweet pepper were constructed with 25%sampling ratio by using two cluster methods (single linkage and UPGMA) and two sampling strategies (random sampling and deviation sampling), respectively. The core collections derived from different sampling strategies and cluster methods were evaluated with the mean, variance, range and coefficient of variation. The results showed that the single linkage cluster method could significantly increase the variances and coefficients of variation of eight traits, obviously better than UPGMA;the deviation sampling was better than the random sampling. Total 102 core accessions of sweet pepper, selected based on Mahalanobis distance, single linkage cluster and deviation sampling, could represent the genetic diversity of the initial collection. This study laid the foundation for the identification of favorable genes and breeding of new varieties in sweet pepper.