乌龟形态性状对体重的影响效果

Effects of morphometric traits on body weight for turtle Chinemys reevesii

选择I龄乌龟291只,测定背甲长、背甲宽、甲桥长、腹甲长、腹甲宽、体高和体重共7个性状,采用相关分析和通径分析方法,计算了以形态性状为自变量对体重做依变量的相关系数、通径系数、决定系数及相关指数,定量地分析了形态性状对体重的影响效果。结果表明,乌龟7个形态性状与体重的相关系数达到极显著水平(p﹤0.01);通径分析揭示了多元分析中多个自变量与依变量的真实关系,背甲长、背甲宽、体高和腹甲长对体重的通径系数达到显著水平,它们是影响体重的重要指标,其中背甲长对体重的直接影响(0.597**)最大,是影响体重的主要因素,其次是背甲宽(0.193**)和体高(0.159**),腹甲长对体重的影响(0.063*)较小;甲桥宽与体重的相关程度很大(0.873),但它与腹甲宽对体重的直接影响都非常小,主要通过其他性状间接影响体重,是影响体重的次要因素,均被剔除;决定系数分析结果与通径分析结果有一致的变化趋势;所选形态性状与体重的复相关指数R2=0.940,说明影响体重的主要自变量指标已经找到,多元回归分析建立了背甲长(X1)、背甲宽(X2)、腹甲长(X4)、体高(X6)对体重(Y)的回归方程,回归截距和相应的回归系数分别是-236.255,2.421,1.188,0.162,1.680;建立回归方程为Y=-236.255+2.421 X1+1.188 X2+0.162 X4+1.680 X6;为乌龟遗传育种提供一定的理论依据和测度指标。

The effects of morphometric traits on body weight for Chinemys reevesii were analyzed.Data were collected from 291 one-year-old turtles from JinGuiWang Industrial Co.Ltd,JiangXi Province.We measured seven parameters,i.e.,the carapace length（X1）,carapace width（X2）,carapace bridge（X3）,plastron length（X4）,plastron width（X5）,body height（X6） and body weight（Y）.The correlation coefficients among the attributes were calculated as well.The first six morphometric traits were selected as independent variables and body weight was used as a dependent variable for path analysis.Accordingly,path coefficients,determinant coefficients,and correlation index（R2） were calculateds.The results showed that all seven correlation coefficients were very significant（p﹤0.01） between each morphometric traits and the weight levels;The path coefficients analysis revealed a truthful relationship within the independent variables and the dependent variable.The path coefficients（Pi） of the carapace length,carapace width,body height and plastron length to the body weight all reached a significant level.The body weight was affected by these major traits.Among three attributes above,carapace length was a key factor to the body weight,with a level of 0.597＊＊.The second and the third were 0.193＊＊ and 0.159＊＊,respectively.Carapace bridge and plastron width,however,had little direct effect on body weightThey were secondary factors for body weight and neglected.The diversification of determination coefficients（di）was consistent with that of path coefficients（Pi）.This indicated that the main variables had been chosen from the results of high correlation index（R2=0.940）.The multiple regression equation of the body weight was obtained including carapace width,carapace length,plastron length and body height.;The constant and corresponding coefficient were-236.255,2.421,1.188,0.162,1.680,respectively.AThe equation among body weight and various traits was described as Y=-236.255＋2.421X1＋1.188X2＋0.162X4＋1.680X6.This study provided theoretical evidence and measurement indicators for heredity and breeding of Chinemys reevesii.