尖吻鲈幼鱼形态性状对体质量影响的通径分析及生长曲线拟合

目的]探明尖吻鲈(Lates calcarifer)幼鱼形态性状对其体质量的影响程度,为尖吻鲈优良形态性状的选育提供参考.方法]分别测量4月龄尖吻鲈的体质量(Y)和25个(X1~X25)形态性状,经相关分析和通径分析找出影响体质量的主要形态性状,并结合逐步回归分析建立4月龄尖吻鲈形态性状对体质量的回归方程,筛选出最优拟合曲线模型.结果]4月龄尖吻鲈体质量与各形态性状间均呈正相关,相关性均达极显著水平(P<0.01);通径分析发现吻至第2背鳍终点的距离(X2)对体质量的直接作用最大(0.589),其次为全长(X4),而吻至第1背鳍起点的距离(X1)主要通过X4、体高(X5)、体宽(X6)和X12间接影响体质量;决定系数分析结果显示,这5个性状对体质量的共同决定系数之和为0.982,说明体质量主要受这些性状的影响;经多元回归分析,建立了4月龄尖吻鲈形态性状与体质量的多元回归方程:Y=-148.455+0.506X4+ 1.382X5+2.268X6-0.064X1+0.342X12.将回归方程中的X4、X5、X6、X11和X12等5个形态性状与体质量分别进行模型拟合,最优拟合模型均为幂函数模型,分别为Y=1.18E-05X43.011、Y=0.001X52851、Y=0.033X62.501、y=0.001X112.636和Y=0.00 1X122.799.结论]对4月龄尖吻鲈进行以体质量为主目标亲本选育时,应以吻至第2背鳍终点的距离(X12)为主要选择性状,全长(X4)、体高(X5)、体宽(X6)和吻至第1背鳍起点的距离(X11)为辅助选择性状.

Path analysis and growth curve fitting of morphological traits to body weight of juvenile Lates calcarifer

Objective] The study was conducted to explore the influences of morphological traits on body weight of juvenile Lates calcarifer,and provide theoretical evidence for selective breeding of L.calcarifer with sound morphological traits.Method] Body weight (Y) and 25 morphological traits (X1-X25) from four-month-old L.calcarifer were measured.The main traits that affecting body weight of juvenile L.calcarifer were searched by correlation analysis and path analysis.The regression equation of morphological traits of four-month-old L.calcarifer to body weight was established by stepwise regression analysis,the optimal fitting curve model was also selected.Result]The results showed that significant positive correlation between morphological traits and body weight of four-month-old L.calcarifer was found,and all the correlation coefficients reached extremely significant level (P＜0.01).The path analysis revealed that distance between proboscis and the end of the second dorsal fin(X12) displayed the largest direct effect(0.589) to body weight,and follow by total length(X4),distance between proboscis and the start of the first dorsal fin(X11) affected body weight indirectly by X4,body height (X5),body width (X6) and X12.The analysis results of determination coefficients showed that the total decision coefficient of six morphological traits to body weight was 0.982,and indicating those morphological traits were the main influencing factors to body weight.The multiple regression equation of four-month-old L.calcarifer morphological traits to body weight was established by multiple regression analysis:Y=-148.455+0.506X4+ 1.382X5+2.268X6-0.064X11+0.342X12, X4,X5, X6,X11 and X12 in the were fitted with body weight respectively,the best fitting model were all power function model:Y=1.18E-05X43.011,Y=0.001X52.851,Y=0.033X62.501,Y=0.001X112.636,Y=0.001X122.799.Conclusion]When selecting parents with body weight of four-month-old L.calcarifer as the main target,the distance between proboscis to the end of the second dorsal fin(X12) should be considered firstly,and total length(X4),body height(X5),body width(X6) and the distance of the proboscis to the origin of the first dorsal fin should be as assistant traits in the selection.