脊尾白虾形态性状对体质量影响的通径分析

为确定适于脊尾白虾人工选育的理想测度指标,实验以4月龄的池塘养殖脊尾白虾为研究对象,随机选取177尾测定体长、全长、头胸甲长、头胸甲宽、头胸甲高、第一腹节高、第一腹节宽、腹部长、额剑上齿数目、额剑下齿数目和体质量共11个指标,采用相关分析和通径分析方法,计算以形态性状为自变量对体质量作依变量的通径系数及决定系数,并定量分析了形态性状对体质量的影响效应.通径分析显示,脊尾白虾体长、头胸甲宽、头胸甲高、第一腹节宽对体质量的通径系数达到极显著水平,是直接影响体质量的主要指标,其中以体长对体质量的直接影响最大,而其余指标对体质量的直接影响均较小,是影响体质量的次要因素,经逐步回归分析后均被剔除；逐步回归分析建立了体长、头胸甲宽、头胸甲高和第一腹节宽对体质量的回归方程,其回归截距及相应的回归系数分别为-3.277、0.470、0.980、0.528和1.942.研究表明,体长、头胸甲宽、头胸甲高和第一腹节宽与体质量的复相关系数(R2)为0.976,为影响体质量的主要自变量.

Path analysis of effects of morphometric attributes on body weight of Exopalaemon carinicauda

The effects of morphometric attributes on body weight of Exopalaemon carinicauda were analyzed by method of path analysis. Data of ten morphometric attributes, including the body length, total length, carapace length, carapace width, carapace height, first abdominal segment height, first abdominal segment width, abdomen length, number of upper frontal eminence spin and number of lower frontal eminence spin, were collected from 177 four-month-old E. carinicauda. The correlation coefficients among all attributes were calculated, and the path coefficients and determination coefficients were calculated in path analysis by taking the body weight as a dependent variable, and the other ten morphometric attributes as independent variables. Path analysis indicates that the path coefficients of four morphometric attributes (body length, carapace width, carapace height, first abdominal segment width) to body weight achieve significant difference (P<0.01) level. These attributes are significant factors determining body weight, among which body length weights the most (0.468**). While the direct effects of total length, carapace length, first abdominal segment height, abdomen length, number of upper frontal eminence spin and number of lower frontal eminence spin to body weight are quite small, therefore, they are the insignificant factors influencing the body weight and eliminated. The stepwise regression analysis establishes a multiple regression equation on the effects of body length, carapace width, carapace height, first abdominal segment width on body weight. The regression intercept and partial regression coefficients of the equation are -3.277, 0.470, 0.980, 0.528 and1.942. Judging from the high multiple-correlation coefficient (R2=0.976), the main attributes (body length, carapace width, carapace height, first abdominal segment width) determining the body weight have been selected.