不同盐度下凡纳滨对虾生长和存活性状遗传评估

为揭示不同盐度环境对凡纳滨对虾家系体质量和存活性状的影响,本研究标记来自72个家系的4348尾对虾,在盐度30(HS组)和盐度15(LS组)条件下混养60 d,分析体质量和存活性状的遗传参数以及基因型与环境互作效应。结果显示,HS组的凡纳滨对虾平均体质量和存活率均高于LS组。估算体质量、存活性状遗传参数,结果显示HS和LS组体质量的遗传力估计值分别为0.51±0.08和0.30±0.07,属高遗传力;转换后存活性状遗传力估计值分别为0.22和0.39,也表现为中高遗传力水平。综合HS和LS组的数据,估算的体质量和转换后存活性状遗传力分别为0.45±0.07和0.31,均表现为高遗传力水平。然而由于收敛原因,在估计模型中未能包括共同环境效应,上述遗传参数估计值偏高。估算基因型与环境互作效应(G×E),结果显示两个盐度间体质量和存活性状均表现为高度遗传相关(0.81~0.90),G×E方差组分与加性遗传方差组分比值均小于0.5,G×E效应均不显著。研究表明,尽管凡纳滨对虾的生长和存活性状在两个盐度下存在一定差异,然而基因型与盐度的互作效应并不显著,由此认为在盐度15~30的范围内,不需要针对不同的盐度建立不同的选育系。

Genetic evaluation for body weight and survival of Pacific white shrimp (Litopenaeus vannamei) at different salinity

The purpose of the present study is to reveal the effects of different salinity on body weight and survival of families of Litopenaeus vannamei. A total of 4348 shrimps from 72 families were raised for 60 d in the 30 salinity and 15 salinity environment. We analyzed the genetic parameters of body weight (BW) and survival rate, and genotype by environment interaction (G×E) of L. vannamei at the 30 and 15 salinity. The results showed that at the 30 salinity, both the average body weight and survival rate were higher than those at the 15 salinity. In this study, the heritabilities of BW at the 30 and 15 salinity were (0.51±0.08) and (0.30±0.07), respectively, which were all high. After conversion, the heritabilities of survival were 0.22 and 0.39, which varied from medium to high. After integrating the data in the 30 and 15 salinity, the heritability of BW and converted heritability of survival were (0.45±0.07) and 0.31, respectively, which were both high. The estimates of genetic parameters might be over-estimated because the common environmental effect was not included in the estimation model due to convergence problem. The results showed there were high genetic correlations (0.81-0.90) for BW and survival between the two salinity. Ratios of G×E variance to additive genetic variance were all less than 0.5, G×E effects for BW and survival were not significant. These results suggested that although there were differences in growth and survival for families of L. vannamei between the 30 and 15 salinity, the G×E was not significant and re-ranking effect was low. Therefore, there is no need to establish a separate breeding line of L. vannamei for each salinity from 15 to 30 salinity environment.