墨西哥湾扇贝(Argopecten irradians concen-tricus)选育系与对照系数量性状对闭壳肌重影响的通径分析
Effect of Quantitative Traits on Adductor Muscle Weight in Selected and Control Lines of Argopecten irradians concentricus

墨西哥湾扇贝(Argopecten irradians concentricus)的闭壳肌重是遗传育种的主要经济性状。本实验测量了壳高、壳长、壳宽、铰合线长、全湿重以及闭壳肌重等6个性状，其中闭壳肌重为因变量，其余5个性状为自变量。分析测得的数据、计算性状的决定系数、对闭壳肌重进行通径分析并且建立两品系的回归方程。结果显示，测量的所有性状的平均数中，选育系均大于对照系，尤其选育系的闭壳肌重更显著地大于对照系；两个品系测量的所有性状分别存在显著的相关性(P < 0.01)。通径分析结果表明，墨西哥湾扇贝选育系中，对于闭壳肌重直接影响最大的是全湿重(Pi = 0.574)，其次为壳长、壳高、壳宽、铰合线长。对照系中直接影响最大的是全湿重(Pi = 0.789)，其次为壳高、铰合线长、壳宽、壳长。各性状决定系数的计算结果与通径分析相一致，均为全湿重的决定系数最大。研究结果表明，墨西哥湾扇贝选育系和对照系在形态上存在显著的差异，今后可以对墨西哥湾扇贝不同品系选择不同的数量性状作为育种的目标性状来间接提高闭壳肌重量。
The adductor muscle weight of A. irradians concentricus is the main characters of genetic selecting. Six characters were measured, including shell height, shell length, shell width, hinge lines length, total wet weight and muscle weight. Among them, muscle weight was dependent variable, and oth-ers were independent variables. We analyzed the measured date, calculated the determination co-efficient of the character, carried out path analysis on the adductor muscle weight and established the regression equation of the two lines. The results showed that the average of all characters measured in the selective lines was larger than that in the control lines, especially the weight of the adductor muscle in the selective lines was more significant than that in others. There was a signifi-cant correlation between all characters measured in two lines (P < 0.01). Path analysis showed that the most direct impact on the weight of the adductor muscle in the selective lines is total wet weight (0.574), followed by shell length, shell height, shell width and hinge lines length. The total wet weight (0.789) in the control lines had the greatest direct impact, followed by shell height, hinge lines length, shell width and shell length. The calculation of the determination coefficient for each character was consistent with the path analysis, and total wet weight was the largest. The results indicated that there were significant differences between the selective and the control lines. It is also speculated that the weight of the adductor muscle can be increased indirectly by selecting dif-ferent quantitative traits of different lines as the target traits.