三疣梭子蟹(Portunus trituberculatus)耐低盐的遗传力估计

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

关键词:  三疣梭子蟹  Ⅱ期幼蟹  80日龄稚蟹  耐低盐  遗传力

Key words:  Portunus trituberculatus  Second phrase crabs  80-day-old crabs  Tolerance to low-salinity  Heritability

摘要:

应用数量遗传学原理和全同胞组内相关法估计三疣梭子蟹(Portunus trituberculatus) Ⅱ期幼蟹和80日龄稚蟹耐低盐性状的遗传力。实验中采用梭子蟹室内人工控制定向交尾方法，构建了32个全同胞家系，包括9个半同胞家系。测定Ⅱ期幼蟹和80日龄稚蟹在盐度11胁迫下的存活率分别为55%和64%，差异显著。利用SPSS软件的一般线性模型(GLM)，计算存活率变量的方差组分，估计耐低盐性状的遗传力。基于全同胞方差组分分析显示，全同胞方差组分估计的遗传力是对三疣梭子蟹两个发育阶段狭义遗传力的无偏估计值，Ⅱ期幼蟹耐低盐遗传力为0.18，属于低度遗传力；而80日龄稚蟹耐低盐遗传力为0.20，属于低度遗传力。因此，家系选育方法更适于三疣梭子蟹耐低盐新品种培育。

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.