摘要
[Objective] This study was conducted to compare the genetic diversity and growth performance of two Litopenaeus vannamei populations at low temperature. [Method] One population（selected population, SP） was produced through inbreeding and 3 years of selection from seven popula- tions of L. vannamei introduced from the United States and Singapore. The other population （hybridized population, HP） was the F1 generation of the crosses between Population SP and some excellent populations introduced from South Korea and Singapore. The growth performance of the two populations at low temperature was compared, and the genetic diversity and genetic differentiation between the two populations were assessed using 13 microsatellite loci. [Result] The shrimps of population HP had better growth performance than those of population SP. The average body weight （BW） for population HP, which was （13.18±3.65） g/ind., was significantly higher than that of population SP, which was （12.20±3.14） g/ind. The coefficient of variation in body weight for population SP was 25.74%, and that for population HP was 27.69%. The other growth indices of popula- tion HP were all higher than those of population SP. One-way analysis of variance （ANOVA） indicated that there were highly significant differences in both BW and width of third abdominal segment （WTAS） between HP and SP（P〈0.001）. The specific growth rate （SGR） and absolute growth rate （AGR） for population HP were （5.09±0.61） %/d and （0.26±0.60） g/d, respectively, while the SGR and AGR for population SP were （4.94±0.57） %/d and （0.24±0.63） g/d., both significantly lower than those of population HP （P〈0.001）. Genetic diversity analysis revealed that the number of alleles （Na） of population HP （Na=7.9） was slightly higher than that of population SP （Na=7.6）. The average polymorphic information content （PIC） of HP and SP populations was similar 0.63 and 0.62, both indicating high level of genetic diversity. The average observed heterozygosity （HQ） of HP and SP was 0.492 and 0.483, and the expected heterozygosity（He） was 0.675 and 0.663, respectively. Both Ho and He of population HP were higher than those of population SP, suggesting that HP had higher genetic diversity than population SP. Moreover, the mean of FsT values at the 13 microsatellite loci between HP and SP was 0.155 6, suggesting there was a significant genetic differentiation between the two populations. [Conclusion] Our results provide a theoretical basis for the breeding of new L. vannamei strains that are resistant to low temperature.
[Objective] This study was conducted to compare the genetic diversity and growth performance of two Litopenaeus vannamei populations at low temperature. [Method] One population（selected population, SP） was produced through inbreeding and 3 years of selection from seven popula- tions of L. vannamei introduced from the United States and Singapore. The other population （hybridized population, HP） was the F1 generation of the crosses between Population SP and some excellent populations introduced from South Korea and Singapore. The growth performance of the two populations at low temperature was compared, and the genetic diversity and genetic differentiation between the two populations were assessed using 13 microsatellite loci. [Result] The shrimps of population HP had better growth performance than those of population SP. The average body weight （BW） for population HP, which was （13.18±3.65） g/ind., was significantly higher than that of population SP, which was （12.20±3.14） g/ind. The coefficient of variation in body weight for population SP was 25.74%, and that for population HP was 27.69%. The other growth indices of popula- tion HP were all higher than those of population SP. One-way analysis of variance （ANOVA） indicated that there were highly significant differences in both BW and width of third abdominal segment （WTAS） between HP and SP（P〈0.001）. The specific growth rate （SGR） and absolute growth rate （AGR） for population HP were （5.09±0.61） %/d and （0.26±0.60） g/d, respectively, while the SGR and AGR for population SP were （4.94±0.57） %/d and （0.24±0.63） g/d., both significantly lower than those of population HP （P〈0.001）. Genetic diversity analysis revealed that the number of alleles （Na） of population HP （Na=7.9） was slightly higher than that of population SP （Na=7.6）. The average polymorphic information content （PIC） of HP and SP populations was similar 0.63 and 0.62, both indicating high level of genetic diversity. The average observed heterozygosity （HQ） of HP and SP was 0.492 and 0.483, and the expected heterozygosity（He） was 0.675 and 0.663, respectively. Both Ho and He of population HP were higher than those of population SP, suggesting that HP had higher genetic diversity than population SP. Moreover, the mean of FsT values at the 13 microsatellite loci between HP and SP was 0.155 6, suggesting there was a significant genetic differentiation between the two populations. [Conclusion] Our results provide a theoretical basis for the breeding of new L. vannamei strains that are resistant to low temperature.
基金
Supported by Central Public-interest Scientific Institution Basal Research Fund,Yellow Sea Fisheries Research Institute,CAFS(20603022017001)
National Natural Science Foundation of China(41676148)
Taishan Scholar Program for Seed Industry and China Agriculture Research System(CARS-48)
