太平洋牡蛎和葡萄牙牡蛎养殖群体数量性状比较分析

Comparison analysis of quantitative traits and path between two cultured populations of Crassostrea gigas and C. angulata

太平洋牡蛎和葡萄牙牡蛎是两个近缘种,属亚种关系,二者都是中国重要的养殖贝类。为了查明这两种牡蛎养殖群体数量性状间的相关性及影响产量的组成因素,分别对179只太平洋牡蛎和140只葡萄牙牡蛎1龄贝的形态性状(壳长、壳宽、壳高)和活体重4个性状进行了测量,并应用通径分析等方法讨论了形态性状对活体重的影响。结果表明,3个形态性状都能够显著地影响活体重,其中壳高的作用是最大的,其对太平洋牡蛎和葡萄牙牡蛎活体重的直接作用分别为19.5%和23.89%。形态性状对太平洋牡蛎和葡萄牙牡蛎活体重间接决定作用差异较大,其中太平洋牡蛎3个形态性状对活体重的间接决定作用较大,均达到10%以上,而葡萄牙牡蛎3个形态性状对活体重的间接决定作用却非常小。利用多元回归分析建立了壳长、壳宽、壳高估计这两种牡蛎活体重(Y1,太平洋牡蛎)和(Y2,葡萄牙牡蛎)的回归方程,分别为:Y1=-119.456 5+1.389 7x1+2.089 0x2+0.777 8x3(R2=0.767 9),Y2=-42.373 9+0.532 8x1+1.289 5x2+0.5 177x3(R2=0.490 9)。本研究结果可为这两种牡蛎的选择育种提供理论依据,即以提高活体重为目标,主要选择壳高,但对太平洋牡蛎还应该加强对壳宽的协同选择。

The Pacific oyster Crossostrea gigas and the Portuguese oyster C. angulata are two close related species and also two of the most important cultured mollusks in China. To clarify correlation among quantitative traits and composi-tions influencing production, four quantitative traits including three morphological traits （Shell length, shell width and shell height）and live body weight of the two oysters were measured and analyzed through path analysis for 140 randomly chosen individuals from the Pacific oyster and 179 randomly chosen individuals from the Portuguese oyster. The results showed that all morphological traits made significant impact on the live body weight in the two oysters, and shell height gave directly predominant effect, which was up to 19.5 % for the Pacific oyster and 23.89% for the Portuguese oyster,respectively. However, morphological traits had significantly indirect effects on the live body weight or had not a signifi-cant difference between the two oysters. All three morphological traits had significantly indirect effect on the live body weight via another morphological trait in the Pacific oyster, and the effect was more than 10%,but the indirect effect was very little in Portuguese oyster. Regression equations between the live body weights（Y1 and Y2 represent the Pacific oyster and the Portuguese oyster, respectively.）and morphological traits of shell length （x1）, shell width （x2）and shell height（x3）were also established, and equations were as followsY 1=-119.456 5＋1.389 7x1＋2.089 0x2＋0.777 8x3 （R2=0.767 9）,Y2=-42.373 9＋0.532 8x1＋1.289 5x2＋0.517 7x3（R2=0.490 9）. The results provided a theoretical basis for selec-tive breeding for Crossostrea gigas and C. angulata,that is,shell height should be firstly selected in order to improve live body weight,whereas shell width should be simultaneously selected for the Pacific oyster.