日本乌贼(Sepiella japonica)形态性状与体质量的相关性及通径分析

Correlation and path coefficient analysis on body weight and morphometric traits of Sepiella japonica

为了研究湛江海域日本乌贼野生群体的形态性状对体质量的影响,随机选取捕捞的野生日本乌贼106尾,分别准确测量体长(X1)、胴长(X2)、体宽(X3)、体高(X4)、眼间距(X5)、触腕长(X6)、第一对腕长(X7)、第二对腕长(X8)、第三对腕长(X9)、第四对腕长(X10)与体质量(Y)等11个性状,采用多元回归分析、相关分析及通径分析方法,计算所有性状间的相关系数,获得相关性状的通径系数、决定系数及相关指数,剖分出形态性状对体质量的直接作用与间接作用。结果表明,10个形态性状与体质量的相关系数极具差异统计学意义(P<0.01);分析得到胴长(X2)、体高(X4)、第一对腕长(X7)为对体质量影响最大的3个性状,其通径系数达极具差异统计学意义(P<0.01),分别为0.580、0.310、0.180;胴长(X2)对体质量的直接作用最大,体高(X4)对体质量的间接作用最大;体高(X4)、第一对腕长(X7)对体质量的间接作用大于直接作用,均主要通过胴长(X2)来间接影响体质量;胴长(X2)的单一决定系数最大,其次是胴长(X2)与体高(X4)共同决定系数,3个性状对体质量的决定系数总和达到0.970,表明它们是影响体质量的主要形态性状;应用逐步回归法建立以Y为应变量,胴长(X2)、体高(X4)、第一对腕长(X7)为自变量的多元线性回归方程:Y=-82.025+11.232X2+14.582X4+12.628X7,决定指数R2为0.970,拟合效果较理想。该研究为后期开展日本乌贼选育测量指标的确定提供参考依据。

In order to study the effect of morphological traits on body weight of S.japonica lived in Zhanjiang sea area,106 wild populations of S.japonica were randomly selected and the body length(X1),mantle length(X2),body width(X3),body height(X4),interocular space(X5),tentacle length(X6),the first tentacle(X7),the second tentacle(X8),the third tentacle(X9),the fourth tentacle(X10)and body weight(Y)were accurately measured respectively.Multiple regression analysis,correlation analysis and path analysis were used to calculate the correlation coefficient,the path coefficient,determining coefficient and correlation index.The direct and indirect effects of morphological traits on body weight were dissected.The results showed that the correlation coefficient between 10 morphological traits and body weight reached the extremely significant level(P<0.01).Mantle length(X2),body height(X4)and the first tentacle(X7)were the three traits that had the greatest impact on body weight.The path coefficients of the three traits reached the extremely significant level(P<0.01),with the path coefficients of 0.580,0.310 and 0.180 respectively.The direct effect of mantle length(X2)on body weight was the largest,while the indirect effect of body height(X4)on body weight was the largest.The indirect effect of body height(X4)and the first tentacle(X7)on body weight was greater than that of direct effect.They indirectly affect body weight through mantle length(X2).The single determining coefficient of mantle length(X2)was the largest,followed by the common determining coefficient of mantle length(X2)and body height(X4).The total determining coefficient of three traits on body weight reached 0.970.It showed that these traits were the main morphological traits affecting body weight.The stepwise regression method was used to establish the multiple linear regression equation with body weight(Y)as the dependent variable,mantle length(X2),body height(X4),and the first tentacle(X7)as the independent variables:Y=-82.025+11.232X2+14.582X4+12.628X7.In the model,the ratio of the sum of squares of total regression and the sum of squares of total residuals was 0.970.The fitting effect was ideal.The above results provided a reference for the determination of measurement index of S.japonica breeding in the later stage.