褐点石斑鱼(♀)×清水石斑鱼(♂)杂交子代幼鱼形态性状对体质量影响的通径分析

Path Analysis of Morphometric Traits on Body Weight for Hybrid Grouper(Epinephelus fuscoguttatus♀ × E.polyphekadion♂)

用相关分析、通径分析及多元回归分析方法分析褐点石斑鱼(Epinephelus fuscoguttatus,♀)与清水石斑鱼(E.polyphekadion,♂)杂交子代(下称杂交石斑鱼)3月龄幼鱼全长(X_1)、体长(X_2)、头长(X_3)、吻长(X_4)、体宽(X_5)、体高(X_6)、尾柄高(X_7)、眼径(X_8)及眼后头长(X_9)等9个形态性状对体质量(Y)的影响效果,并建立最优回归模型。结果表明,3月龄杂交石斑鱼9个形态性状与体质量相关性均极显著(P<0.01),其中,全长、体高、体宽及尾柄高等4个性状对体质量的直接作用均达极显著水平(P<0.01),总决定系数为0.933;全长对体质量的直接作用最大(0.713),对体质量的决定系数最高(0.508),体高、体宽及尾柄高对体质量直接作用均较小,主要通过间接作用来影响体质量。以逐步回归分析方法建立以全长、体高、体宽及尾柄高估计杂交石斑鱼体质量的最优回归方程:?=–35.301+3.678 X_1+3.234 X_6+2.432 X_5+2.226 X_7。

133of3-months aged hybrid(Epinephelus fuscoguttatus♀×E.polyphekadion♂)were randomly selected and10morphological traits including the total length(X1),standard length(X2),head length(X3),snout length(X4),body width(X5),body depth(X6),caudal peduncle depth(X7),eye diameter(X8),head length after eyes(X9),and body weight(Y)were measured.The correlation coefficients,path coefficients and decision coefficients were calculated,then the effects of morphometric traits on body weight were analyzed.The results showed that the correlation coefficients between all morphometric traits and body weight were extremely significant(P<0.01).The path coefficients of four morphometric attributes(X1,X6,X5,X7)to body weight reached significant difference level(P<0.01).Among them,X1was the most predominant variable to affect body weight(0.713).The results of determinant coefficients analysis revealed that X1had the predominant determinative effect(0.508).X6,X5,X7exhibited slight direct effect and significant indirect effect through other phenotypic features on the body weight.The trend of determination coefficient analysis was similar to that of path analysis.High multiple correlation index(R2=0.933)between phenotypic features and body weight indicated that the selected traits were practically useful.The stepwise regression analysis established a multiple regression equation on the effects of body weight were presented as?=-35.301+3.678X1+3.234X6+2.432X5+2.226X7.These results provide a reference for the study of the relationship between morphometric traits and body weight of hybrid grouper.