Genetic parameters and genotype by environment interaction for cold tolerance, body weight and survival of the Pacific white shrimp Penaeus vannamei at different temperatures

The inability of Penaeus vannamei to tolerate low temperatures is of major economic concern in temperate climates, as it reduces their growing season and leads to over-winter mortality. In this study, the heritability of body weight and survival under two grow-out temperature conditions, genotype by environment interaction for body weight and survival at different grow-out temperatures, and the heritability of cold tolerance traits of P. vannamei were investigated and estimated. The heritability estimates for body weight in normal controls (CK) and low-temperature groups (LTT) were, respectively, moderate (0.3191 +/- 0.0622) and low (0.1368 +/- 0.0889), and those for survival were all low (0.1094 +/- 0.0265 and 0.0598 +/- 0.0229, respectively). The genetic correlations between the CK and LTT groups for body weight and survival were 0.4788 +/- 0.2073 and 0.2968 +/- 0.2284 respectively, and both of them showed significant differences from unity (P < 0.05). Furthermore, their K-values were all higher than 0.50, which indicated that the genotype-by-environment interaction effect was substantial in both growth and survival at different temperatures. The cold tolerance heritability estimated from a cold temperature challenge (18 degrees C to 8 degrees C) using cooling degree hours for each individual (CDH) and survival rate of each family at half lethal time (SR50) were low (0.0258 +/- 0.0205 and 0.0211 +/- 0.0196 respectively), and negative genetic correlations between these cold tolerance traits and body weight (-0.7702 +/- 0.4583 and -0.8253 +/- 0.4553 respectively) were also estimated from the cold challenge. However, they showed no statistically significant differences from zero. Thus, more research needs to be conducted on the more accurate heritability of cold tolerance trait and genetic correlations between traits in P. vannamei to further improve the achievement of breeding goals. (C) 2015 Elsevier B.V. All rights reserved.