Genetic Parameters Of Growth,Survival And Resistance Traits For Selective Breeding Population In Marsupenaeus Japonicus

Owing to its high economic value,Marsupenaeus japonicus has been commercially important as a primary oceanic aquaculture species from Hainan to Liaoning in China.Brood stock relys on natural fishing and without systematic breeding program.It is urgent to breed new shrimp strain with high stability of genetic traits for sustainable development of shrimp culture.Sixty-eight full-sib families of M.japonicus were produced by 68 sires and 68 dams,which were collected from Taiwan population.This study concentrates on selective breeding of M.japonicus to carry out the following three researches.1.Estimation of genetic parameters and breeding value for growth and survival of the selective breeding population in M.japonicus at different growth stage.Genetic parameters and breeding value for growth and survival traits were estimated by mixed linear models and restricted maximum at different growth stage of M.japonicus.The results show that the growth traits had a medium heritability(0.1545±0.0505~0.1992±0.0371)at different life stages(45,75,105,135,165,195,225,255,285d)and the survival traits had a low heritability(0.003±0.001)at 285 days.The phenotypic and genetic correlations between growth traits at different ages were generally high(P<0.01),which were 0.5052±0.0280~0.7121±0.0188 and 0.7177±0.0131~0.9896±0.0034 respectively,but the phenotypic and genetic correlations between growth traits and survival traits were low(0.005±0.06~0.097±0.29).2.Estimation of genetic parameters for growth and low salinity tolerance traits of M.japonicus.The aim of current study was to estimate the genetic parameters for growth and low salinity tolerance traits in M.japonicas at day 120.There were a total of 6120 tagged shrimps represent sixty-eight full-sib families evaluated for growth and low salinity tolerance traits in this study.Genetic parameters for growth and low salinity tolerance traits were estimated by Restricted Maximum Likelihood Method in M.japonicus.The results show that the tolerance of half lethal salt concentration and coefficient of variation were 6.749‰ and 19.30%,which suggest that low salinity tolerance traits were genetically stable.The low salinity tolerance traits had a lowheritability(0.0414±0.0826).The phenotypic and genetic correlations between growth traits and low salinity tolerance traits were low but positive,which were 0.1001±0.4425~0.1598±0.4417(P<0.01),which suggest that low salinity tolerance traits can be achieved by indirect selection on growth traits.3.Estimation of genetic parameters for growth and high ammonia tolerance traits in M.japonicusat different ages.The aim of current study was to estimate the genetic parameters for growth and high ammonia tolerance traits in M.japonicus at day 150 and day 270.There were a total of tagged shrimps represent sixty-eight full-sib families evaluated for growth and high ammonia tolerance traits in this study.Genetic parameters for growth and high ammonia tolerance traits were estimated by general linear animal mixed model and threshold model in M.japonicus.The results show that the tolerance of half lethal ammonia concentration were 42.055mg/L and 48.182 mg/L.The high ammonia tolerance traits had a low heritability(0.0327±0.0021)and(0.0287±0.0273)at day 150 and day 270.The phenotypic and genetic correlations between growth traits and high ammonia tolerance traits were low,which were-0.0820±0.0200~0.0800±0.1297 and-0.0220±0.0169~0.1741±0.0131,which suggest that high ammonia tolerance traits can be achieved by indirect selection on growth traits.The results show that the multi-characters selection should be applied in improving growth traits and high ammonia tolerance traits of M.japonicus.