野生大珠母贝形态性状对湿重和壳重的相关性及通径分析

Correlation and path analysis of morphological traits to wet weight and shell weight of wild Pinctada maxima

【目的】确定野生大珠母贝形态性状对湿重和壳重的直接或间接作用及其决定系数,为人工选育目标性状提供最佳的测量指标。【方法】以在海南三亚市西岛附近海域捕捞的157只贝龄超过2龄的野生大珠母贝为研究对象,对其形态性状[壳长(x1)、壳高(x2)、壳宽(x3)、绞合线长(x4)]及湿重(y1)和壳重(y2)进行测量后,采用多元回归分析确定形态性状与湿重和壳重间的相关性,通过相关性和通径分析获取影响湿重和壳重的主要形态性状,并建立最优回归方程。【结果】大珠母贝各性状指标的变异系数范围为8.29%～41.80%,且各性状指标间的相关性均达极显著水平(P<0.01)。通径分析结果表明,对湿重和壳重直接影响作用最大的形态性状分别是壳高(0.468)和壳宽(0.573),其中,壳高对湿重的决定系数为0.219,壳宽对壳重的决定系数为0.381;对湿重和壳重间接决定作用最大的均为壳高通过壳宽,对应的决定系数分别为0.285和0.381。剔除对湿重和壳重不显著的形态性状后,分别构建大珠母贝形态性状与湿重和壳重间的回归方程,对湿重的回归方程为y1=3.245x1+7.747x2+23.521x3-2383.820(R2=0.897),对壳重的回归方程为y2=4.888x2+27.089x3-1531.922(R2=0.858)。【结论】在大珠母贝的选育过程中,当以湿重为选育目标时应以壳高为直接选择,同时加强对壳宽的协同选择;而在以壳重为选育目标时应以壳宽为直接选择,同时加强对壳长的协同选择。

【Objective】The direct or indirect effects of morphological traits on the wet weight and shell weight of wild Pinctada maxima and the determination coefficients were determined,in order to provide the best measurement index for artificial breeding target traits.【Method】One hundred and fifty-seven wild P.maxima individuals more than 2 years old,which were caught in sea areas around Shixi Island,Sanya,Hainan,were measured four morphological traits including shell length(x1),shell height(x2),shell width(x3)and hinge length(x4),wet weight(y1)and shell weight(y2)were also detected.Multivariate regression analysis was used to determine the correlation between four morphological traits and wet weight and shell weight.Correlation analysis and path analysis were used to obtain the main morphological traits affecting wet weight and shell weight,and an optimal regression equation was established.【Result】The results showed that,the coefficient of variation between the traits of P.maxima was from 8.29%to 41.80%,four morphological traits attributed extremely significantly(P<0.01)correlated to wet weight and shell weight.According to path analysis,the largest direct effects on wet weight and shell weight were shell height(0.468)and shell width(0.573)respectively,the coefficient of determination of shell height to wet weight was 0.219,and the coefficient of shell width to shell weight was 0.381.The largest indirect effects on wet weight and shell weight was shell height through shell width,and their determination coefficients were 0.285 and 0.381.Eliminating the insignificant morphological traits on wet weight and shell weight,regression equations between P.maxima morphological traits and wet weight,shell weight were established.The equation for wet weight was y1=3.245x1+7.747x2+23.521x3-2383.820(R^2=0.897),for shell weight was y2=4.888x2+27.089x3-1531.922(R^2=0.858).【Conclusion】During selecting and breeding of P.maxima,when wet weight is the breeding target,shell height should be directly selected and the shell width should be selected simultaneously.When shell weight is the target of breeding,shell width should be selected directly,and at the same time,the cooperative selection of shell length should be strengthened.