凡纳滨对虾群体自交与杂交子代幼体对低温、低盐抗逆性与生长比较

为提高凡纳滨对虾种苗质量,探索群体选择育种和杂交育种方法在凡纳滨对虾大规模人工育苗生产中的应用,对1个经过人工选择的凡纳滨对虾群体A的自交和杂交子代的抗逆性和生长性状进行了比较。群体A是2008年来自美国种虾的子一代,并经过2个世代的人工选择和自交传代。群体B为2010年来自广东的繁育群体。A群体自交,及其与B群体的正、反杂交,产生3组不同交配组合的子代。对3个组合后代仔虾幼体的抗低温、低盐能力及养成期的生长性状进行比较分析,结果表明,以A群体为母本的杂交组AB抗逆性最强,以B群体为母本的杂交组BA抗逆性次之,而A群体自交组抗逆性最弱。在低温(13.0±0.9) ℃和低盐4.7条件下,AB组存活率分别比AA组高27.6%和64.4%。3个组合养成期的体质量生长速度为AB组(253±55) mg/d、 BA组(208±52) mg/d、AA组(219±36) mg/d,AB组比BA组快21.6%,比AA组快15.5%。研究表明,凡纳滨对虾的杂交优势与亲本的提纯、选优密切相关。

A comparative study on growth,low-salinity and low-temperature resistance among the inbred and hybrid offsprings at larval stages for Litopenaeus vannamei

In order to improve the quality of Litopenaeus vannamei seedlings and explore the application of mass selection and crossbreeding methods in large-scale production of artificial breeding,a comparative study on inbred and hybrid offsprings within stock A was carried out.Stock A was introduced from America in 2008 and was then artificially selected for two generations.Stock B was selected from Guangdong cultured population in 2010.The inbred line AA(A♀×A♂)and reciprocal cross lines AB(A♀×B♂)and BA(B♀×A♂)between these two stocks were established.Then a comparative study on growth,low-salinity and low-temperature resistance at larval stages was conducted among these three lines.The results showed that the offsprings for AB showed the best resistance capacity of low-temperature and low-salinity among three lines.Under the low temperature of(13.0±0.9) ℃ and the low-salinity of 4.7 conditions,the survival rates for AB line was 27.5% and 64.6% higher than that of the inbred line AA,respectively.The growth rate for body weight at the grow-out stage were(253±55) mg/d for AB line,(208±52) mg/d for BA line and(219±36) mg/d for AA line.The growth rate for AB line was 21.6% and 15.5% faster than that of BA and AA lines.The results indicated that heterosis of Litopenaeus vannamei was closely related with mass selection for broodstock.