家蚕饲料效率的遗传通径分析

以7个原种和杂交种的5龄蚕为实验材料,采用0.5指数限制给桑法,调查了食下留存率、茧层生产效率、产卵效率三项主要的饲料效率性状及其构成原因,进行了遗传通径分析。结果表明:(1)这些饲料效率性状(效应因素)和其构成原因(原因因素)间,以及各原因间均存在正的遗传相关。(2)原因因素中,体重增加量、茧层量、产卵量的直接影响(直接通径系数)均为正向效应,而间接影响均为负向效应;其他原因因素的直接影响几乎都为负效应,而间接影响几乎都为正效应。(3)从育种观点看,要选育饲料效率高的品种,宜在适当控制给食条件下选择目的生产物量(体重增加量、茧层量、产卵量)高的蛾区或个体继代。

Genetic path analysis of feed efficiency in silkworm Bombyx mory

The fifth instar larvae of seven parent races and hybrids were used in the experiment. Three major characters of feed efficiency, the conversion efficiency from ingested food to body substance, to cocoon layer, to weight of eggs laid, and their cause factors were measured under restricted feeding such as feed index 0.5. Analysis of genetic path coefficients was carried out based on these basic data. The results were as follows. 1. There were genetic positive correlation between three feed efficiency characters ( effect factors ) and their cause factors, as well as between these causes. 2. In the cause factors, the direct influence ( direct path coefficients ) of body weight gain, cocoon shell weight, weight of eggs laid were all positive, and their indirect influence ( indirect path coefficients) were negative. On the other hand, the direct influence of other causes was almost negative and the indirect effects were positive. 3. From the breeding view point, in order to breed high feed efficient race, it would be relatively effective to Select the moth batch or individuals which had high body weight gain, cocoon shell weight, weight of eggs laid for reproduction and multiplication by control feeding.