脊尾白虾生长和繁殖性状的遗传参数估计

Estimation of genetic parameters for growth and reproduction traits in Exopalaemon carinicauda

中文关键词: 脊尾白虾  生长性状  繁殖性状  遗传力  遗传相关

英文关键词: Exopalaemon carinicauda  Growth trait  Reproductive trait  Heritability  Genetic correlation

中文摘要:

      为估计脊尾白虾(Exopalaemon carinicauda)生长和繁殖性状的遗传参数，本研究采用巢式交配设计建立家系，构建了40个脊尾白虾全同胞家系，其中，包括25个半同胞家系，利用一般线性模型估计了脊尾白虾50日龄和80日龄体长、总腹节长、体重以及抱卵量、单位体重抱卵量、单位体长抱卵量和第1次产卵时间性状的遗传力、表型相关和遗传相关。结果显示，50日龄体长、总腹节长、体重的遗传力分别为0.27~0.69、0.31~0.44和0.20~0.65，80日龄体长、总腹节长和体重的遗传力分别为0.39~0.54、0.31~0.47、0.33~0.71；抱卵量、单位体重抱卵量、单位体长抱卵量和第1次产卵时间的遗传力分别为0.45~0.52、0.30~0.49、0.43~0.48和0.33~0.77；经过t检验，全同胞方差组分估计的遗传力达到极显著水平(P<0.01)。因此，脊尾白虾的生长和繁殖性状的狭义遗传力的无偏估计值为全同胞方差组分估计的遗传力。体重与体长、抱卵量性状的遗传相关系数分别为0.951 4和0.205 8，体重与体长、抱卵量性状的表型相关系数分别为0.742 0和0.212 4。研究表明，脊尾白虾体长、总腹节长及体重3个生长性状和抱卵量、单位体长抱卵量、单位体重抱卵量及第1次产卵时间4个繁殖性状均达到中高等遗传力水平，体重和体长性状为高度正相关，体重和抱卵量性状为低度正相关。本研究为脊尾白虾高繁殖力性状良种选育工作提供了数据参考。

英文摘要:

      The ridgetail white shrimp (Exopalaemon carinicauda), belonging to the Palaemonidae family of crustaceans, is an economically important small-to-medium-sized shrimp in China that is naturally distributed on the coasts of the Yellow and Bohai Seas. Due to its rapid growth and high tolerance for environmental stress, the scale at which E. carinicauda is cultured has expanded in recent years. The reproductive performance of broodstock is crucial to the yield and quality of larvae, as the egg production of E. carinicauda is much lower than that of other economically important shrimps. Meanwhile, E. carinicauda seedling production mainly relies on wild shrimp or breeding parents, resulting in low fertility and poor seed quality, such that the cultivation of E. carinicauda is often hindered by a slow growth rate and poor disease resistance, seriously limiting the development of the E. carinicauda farming industry. Optimizing growth and reproductive traits is vital for the animal aquaculture industry, as these traits are crucial for developing high-quality seedlings and are directly related to yield. Cultivating new varieties with high fertility and fast growth rates can effectively improve the aquaculture of E. carinicauda. In this study, we estimated the genetic parameters of growth and reproduction traits in E. carinicauda. We constructed 40 full-sibling lines of E. carinicauda and 25 half-sibling lines by pairing one male with two females. Thirty shrimps were randomly selected from each line at 50 d and 80 d of age, and the body length, total abdominal length, and body weight were measured to calculate the genetic parameters. The number of eggs, body length, body weight, and incubation time of the first spawning were measured to ensure that the culture conditions for each line were consistent. The main baits used during incubation were folded brachyuran rotifers (Brachinonus plicatilis) and brine shrimp (Artemia sinica). The heritability, phenotypic correlations, and genetic correlations of body weight, body length, total abdominal length traits, time of first spawning, absolute egg count, egg count per unit of body length, and egg count per unit of body weight in E. carinicauda were estimated at the ages of 50 and 80 d using a general linear model. The results showed that the heritability estimate values for body length, total abdominal length, and body weight at 50 d were approximately 0.27–0.69, 0.31–0.44, and 0.20–0.65, respectively, and those for body length, total abdominal length, and body weight at 80 d were approximately 0.39–0.54, 0.31–0.47, and 0.33–0.71, respectively. The heritability estimate values for the number of eggs, the number of eggs per unit of body length, the number of eggs per unit of body weight, and the time of the first spawning were approximately 0.45–0.52, 0.30–0.49, 0.43–0.48, and 0.33–0.77, respectively. The heritability estimate values for all three growth-related traits and four reproduction traits almost reached the level of medium-high heritability. The heritability estimate values for growth and reproduction traits based on full siblings reached a highly significant level according to t-tests. Therefore, the unbiased estimates of narrow-sense heritability for growth and reproduction traits were those estimated by the full-sibling variance component. The phenotypic and genetic correlations for growth and reproduction traits were approximately 0–0.756 9 and –0.006 5–0.951 4, respectively. The genetic correlation coefficients of body weight with body length and egg count were 0.951 4 and 0.205 8, respectively. The phenotypic correlation coefficients of body weight with body length and egg count were 0.742 0 and 0.212 4, respectively. However, the genetic and phenotypic correlations between body length and egg count were poor. Therefore, we suggest that body length and egg count be set as two different targets in breeding programs. The results indicate that the heritability estimate values for body length, total abdominal length, and body weight at 50 and 80 d and for reproduction traits including egg count, egg count per unit length or weight, and time of first spawning almost reached the level of medium-high heritability. The growth and reproductive traits of E. carinicauda can be selected through individual or population-phenotypic selection. The above results provide important basic data to support the breeding of E. carinicauda and have considerable application value for future breeding programs.