低温胁迫条件下中国明对虾生长性状和耐低温性状的遗传参数评估

Evaluation of Genetic Parameters for Growth and Cold Tolerance Traits in Fenneropenaeus chinensis Under Low-Temperature Stress

本研究采用室内人工降温的方式,对69个中国明对虾(Fenneropenaeus chinensis)家系共1327尾成虾进行了耐低温实验,测定其生长和耐低温性状;并利用混合模型方程,通过平均信息约束极大似然法进行遗传力和遗传相关估计。采用2种动物模型对中国明对虾成虾低温下体重、体长的遗传力进行评估,模型1加入了共同环境效应,模型2没有加入共同环境效应。由模型1获得的体重、体长的遗传力分别为(0.206±0.177)、(0.187±0.179),由模型2获得的体重、体长的遗传力分别为(0.317±0.065)、(0.298±0.063),均为中低等遗传力。经似然比检验体重、体长在模型1和模型2间的似然比值均无显著差异(P>0.05),表明模型1和模型2之间无显著差异,模型2为较优遗传模型。以半致死时的存活状态作为耐低温性状指标,遗传力为(0.169±0.078),为低等遗传力。低温下体重、体长之间的表型和遗传相关分别为(0.823±0.010)和(0.969±0.018),为高度正相关;低温下体重、体长与半致死时的存活状态的表型相关分别为(0.187±0.030)和(0.218±0.030),为低度正相关;而遗传相关分别为(0.517±0.205)和(0.538±0.203),为中度正相关。本研究表明,对生长性状进行的选育不会降低其耐低温能力,中国明对虾耐低温性状可与生长性状进行共同复合选育。

In the present study, a preliminary evaluation was conducted on the cold tolerance and growth traits of 69 Fenneropenaeus chinensis by indoor artificial cooling. A linear mixed model with average information restricted maximum likelihood was used to evaluate the genetic parameters. Two animal models were used to evaluate the heritability of body weight（BW） and body length（BL） under low-temperature stress in F. chinensis. The heritability of BW and BL observed in model 1 were（0.206±0.177） and（0.187±0.179）, respectively, and for model 2, these were（0.317±0.065） and（0.298±0.063）, respectively, which ranged between medium to low. The differences between the two models were tested by likelihood ratio test, and the likelihood ratio values for Model 1 and Model 2 were 1.640 and 1.764, respectively, which were not significantly different（P〉0.05）. The results showed that the two models were not significantly different, and that model 2 was the optimal model. The heritability of the survival status at half lethal time（SS50） among cold tolerant traits was（0.169±0.078）. The phenotypic and genetic correlation coefficients between BW and BL under low-temperature stress were（0.823±0.010） and（0.969±0.018）, respectively, which were relatively high. The phenotypic correlation coefficients between BW and SS50; and BL and SS50 were comparatively low with values（0.187±0.030） and（0.218±0.030）, respectively. The genetic correlation coefficient between BW and SS50; and BL and SS50 were comparatively high with values（0.517±0.205） and（0.538±0.203）, respectively. The results showed that during breeding of F. chinensis, the cold tolerant variety can be selected together with growth traits.