南沙群体大珠母贝表型性状比较及通径分析

Comparison and path analysis of phenotypic traits of wild Pinctada maxima in Nansha population

为确定南沙群体野生大珠母贝(Pinctada maxima)外部形态性状对其体质量的影响程度,为人工选育提供参考指标,以南沙群岛自然海域捕捞的1龄野生大珠母贝为研究对象,对其外部形态性状壳长、壳高、壳宽和绞合线长及其体质量进行测量统计,并进行相关性、多元逐步回归和通径分析。结果显示,大珠母贝的各性状指标变异系数区间为(13.751%,38.947%),并且各性状相关系数均达到极显著水平(P<0.01);剔除差异不显著的形态性状建立最优回归方程,其中R 2=0.933;通径分析结果显示,南沙群体大珠母贝对体质量的直接作用最大的外部形态性状为壳宽(0.439),而壳长通过壳高对体质量的间接作用影响最大(0.384),其中壳宽对体质量的决定系数为0.193,壳宽通过壳高对体质量的决定系数最大(0.312)。结果表明,当以南沙群体野生大珠母贝体质量为选育目标时,应注重对壳宽的选择。

In order to determine the influence of external morphological traits of wild Pinctada maxima in Nansha population on its body weight and provide the reference index for artificial breeding,the 1-year-old wild P.maxima collected in the natural sea area of Nansha Islands were taken as the research objects.The shell length,shell height,shell width and hinge length of external morphological traits and the body weight were measured and counted,and the correlation,multiple stepwise regression and path analysis were carried out.The results showed that the coefficient of variation of each trait index was(13.751%,38.947%),and the correlation coefficients of each trait reached a very significant level(P<0.01).The optimal regression equation was established by excluding morphological traits with no significant difference,R 2=0.933;The path analysis results showed that the external morphological traits with the greatest direct effect on body weight of P.maxima in Nansha population were shell width(0.439),and the indirect effect of shell length on body weight through shell height was the greatest(0.384).The determination coefficient of shell width on body weight was 0.193,and that of shell width through shell height was the greatest(0.312).The results show that the selection of shell width should be taken into account when the body weight of wild P.maxima in Nansha population is used as the breeding target.