钝缀锦蛤选育群体F2生长性状相关性及遗传力分析

为开展钝缀锦蛤早期群体选育,通过生长性状研究群体选育的潜力,以经1代群体选育钝缀锦蛤(Tapes dorsatus)为亲本,通过阶段性移养的方式建立7个半同胞家系和混养F_2闭锁群体,分析12月龄和18月龄F_2群体的生长性状相关性,基于约束极大似然法(Restricted Maximum Likelihood,REML)估算12月龄钝缀锦蛤生长性状遗传力。结果显示钝缀锦蛤生长性状相关性达到极显著水平(P0.01)。根据多元回归分析结果,12月龄F_2群体壳长、壳高和壳宽对体质量直接作用为0.377,0.370,0.276;18月龄F_2群体壳长、壳高和壳宽对体质量直接作用为0.389,0.361,0.351。2个阶段壳体性状对体质量的直接作用相近,且直接作用大于间接作用,壳长对体质量直接作用最大。相比12月龄,8月龄F2群体壳宽对体质量的直接作用提高。12月龄和18月龄F2群体壳长(x_1)、壳高(x_2)、壳宽(x_3)对体质量(y)的回归方程分别为y=-48.724+0.513x_1+0.754x_2+0.882x_3(R~2=0.848)和y=-94.689+0.772x_1+1.141x_2+1.608x_3(R~2=0.864)。估算壳长、壳高、壳宽、体质量半同胞个体遗传力分别为0.14±0.16、0.10±0.08、0.49±0.28、0.29±0.14,壳宽的遗传力最高,表明壳宽是钝缀锦蛤选育的首选性状。本研究结果为钝缀锦蛤群体选育提供基础数据。

Correlation and Heritability Analysis on Growth Traits for F2 Population of Tapes dorsatus

In order to carry out the early population breeding of Tapes dorsatus,the potential of population breeding was studied through growth traits. Taking the population breeding of F₁ generation tapered dorsatus (T.dorsatus) as parents, 7 half-sib families and polyculture F₂ closed population were established through cultivation in certain period. The correlation between the growth traits of 12 months old and 18 months old F₂ population was analyzed. Based on the restricted maximum likelihood (REML) method, the heritability of the growth traits of 12 months old T.dorsatus was estimated. The results show that the correlation of growth traits of T.dorsatus reaches a very significant level (P<0.01). According to the results of multiple regression analysis, the direct effects of shell length, shell height and shell width on body weight of the F₂ population at 12 months old are 0.377, 0.370 and 0.276.The direct effects of shell length, shell height and shell width on body weight of the F₂ population at 18 months old were 0.389, 0.361 and 0.351.The direct effects of shell traits on body weight in the two stages are similar, and the direct effect is greater than the indirect effect. Shell length has the greatest effect on body weight, and the direct effect of shell width on body weight of F₂ population at 18-month-old is improved. The regression equations of shell length (x₁),shell height (x₂) and shell width (x₃) on body weight (y) of F₂ population at 12 and 18 months old are y=-48.724+0.513x₁+0.754x₂+0.882x₃(R²=0.848) and y=-94.689+0.772x₁+1.141x₂+1.608x₃ (R²=0.864),respectively.The estimated heritability of half-sib individuals of shell length, shell height, shell width and body weight are 0.14±0.16,0.10±0.08,0.49±0.28 and 0.29±0.14.The heritability of shell width is the highest, indicating that shell width is the preferred trait for selective breeding.The results will provide basic data for population selection and breeding of T.dorsatus.