Genetic parameters and response to selection for harvest body weight of pacific white shrimp, Litopenaeus vannamei

Genetic parameters and response to selection were estimated for the harvest body weight of Litopenaeus vannamei. The data consisted of 24072 progeny from 178 sires and 171 dams in two generations (G(0) and G(1)) with a nested mating structure. All families were randomly divided into two groups and then cultured in two farms at different locations (Huanghua and Qingdao). The heritability estimates from G(0) and G(1) were 0.278 +/- 0.136 and 0.423 +/- 0.065 respectively. Over two generations, the heritability estimate was 0.335 +/- 0.087, and the common environmental effect was 0.084 +/- 0.031. A bivariate animal model was used to estimate variance and covariance components, whereby the body weight in the two farms was treated as a genetically distinct trait. Genetic correlation was close to unity (0.943 +/- 0.066), indicating that a genotype by environmental interaction for harvest body weight was small. The response to selection in harvest body weight was estimated using two methods (the realized and predicted responses). The realized response was estimated from the difference in the least squares means of body weight for the selection and control populations. The predicted response was obtained from the difference in the mean estimated breeding values between generations. The realized response was 2.30%, while the predicted responses were 2.00% and 1.37% for within- and across-generation datasets using two sets of genetic parameters respectively. The results would provide crucial information in pacific white shrimp breeding programs in China.