Total 380 4-month-old amur sturgeon( Acipenser schrenckii)were randomly sampled,and their 11 phenotypic characters( including full length,body length,head length,snout length,length of head behind the eye,tail handle height,tail length,eye diameter,body thickness,body weight,body height)were measured. By correlation analysis and path analysis,the au-thor studied the correlation coefficient,path coefficient and determination coefficient between body weight and 11 phenotypic charac-ters of amur sturgeon,and explicated the main phenotypic characters affecting the body weight of 4 -month-old amur sturgeon. The results showed that all correlation coefficients between body weight and each morphological character reached a very significant level(P﹤0. 01). The main phenotypic characters which affected the body weight of 4-month-old amur sturgeon were full length, body height,tail handle height and eye diameter. Both the path coefficient and determination coefficient between full length and body weight were the highest,being 0. 395** and 15. 60% respectively. Eye diameter exhibited a slight direct effect(0. 160**) and a significant indirect effect(0. 4152)on the body weight. The results of determination coefficient analysis were similar to those of path analysis. The total determination coefficient between all phenotypic characters and body weight was 0. 882,which was equal to the value of correlation index R2 . Through stepwise regression analysis and significance test for partial regression coefficients,the multiple regression equation describing the relation between body weight( y)and full length( x1 ),body height( x2 ),eye diameter (x3),tail handle height(x4)of amur sturgeon was built as follows:y= -92.751+3.018x1 +12.472x2 +50.765x3 +35.335x4.%随机选取4月史氏鲟幼鱼380尾，测量其体重、全长、体长、体厚、体高、头长、吻长、尾长、尾柄高、眼径、眼后头长共11个形态学指标。采用相关分析和通径分析方法，研究了史氏鲟4月龄幼鱼外部形态对体重的相关系数、通径系数及决定系数，明确了影响史氏鲟4月幼鱼体重的主要外部形态性状。结果表明，各形态性状与体重的相关系数均达到极显著水平（P ﹤0.01）；影响史氏鲟4月幼鱼体重的主要性状是全长、体高、眼径、尾柄高；全长对体重的通径系数最大（0.395**），对体重的决定系数最高（15.60%）；眼径对体重的直接作用较小（0.160**），主要是通过间接作用来影响体重（0.4152）；决定分析的结果和通径分析的变化趋势一致；各形态性状对体重总的决定系数Σd＝0.882，它与相关指数R2的数值相等；通过逐步回归分析方法，经偏回归系数显著性检验，建立了体质量为因变量，全长、体高、尾柄高和眼径为自变量的多元回归方程为：y＝-92.751＋3.018x1＋12.472x2＋50.765x3＋35.335x4。
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