Estimation of the Heritability of the Tolerance to Low-Salinity in Portunus trituberculatus

Abstract:

Along with the rapid expansion of the culture of Portunus trituberculatus, various problems, such as diseases, larval degeneration, and natural resource depletion, have largely led to economic losses. Salinity is an osmotic pressure-related environmental and water quality factor which has great impact on the growth, the respiratory metabolism, the immune defense, and the survival of P. trituberculatus. In this study, we estimated the heritability of the body weight of P. trituberculatus with the intra-group correlation of full-sibs. A total of 400 mature crabs were taken from the culture, and 100 sires and 300 dams were mated in 1♂×3♀, and 9 half-sib families and 32 full-sib families were generated. We divided 450 individuals equally into 9 groups from each family at Ⅱ stage, and 270 individuals were divided equally into 9 groups from each family at the 80-day stage. The subjects were stressed under salinity 11 and then the survival rates were measured. Causal components of phenotypic variance were calculated with the GLM procedure of SPSS software. The heritability of Ⅱ stage and 80-day stage was 0.120.24 and 0.130.26 respectively. No significant difference was found in the heritability between the maternal and the paternal genetic variances. However, there was a significant difference in the components variance of full-sibs within sires and dams. The values from components of variance of full-sibs within sires and dams were 0.18 and 0.20 for Ⅱ stage and 80-day stage respectively, and they were precise and unbiased. These results suggested that the heritability of the tolerance to low salinity was low in P. trituberculatus.