Heritability Estimates Of "Huanghai No. 1" Shrimp (Fenneropenaeus Chinensis) For Growth And Resistance To High PH And High Ammonia

Heritability is one of the important parameters in quantitative genetics, and is the important basis for selective breeding. Heritability estimate is used to explain the genetic rules of quantitative traits, and it is also helpful to estimate breeding value, establish selective projects and breeding programs. In this study,"Huanghai No.1"shrimp (Fenneropenaeus chinensis) which was the first new successful breeing animal aquaculture species in China were used to estimate the heritabilities for growth and resistance to high pH and high ammonia at 3 and 4 months. 9 half-sib groups and 21 full-sib families were produced by an unbalanced nest design that each male mated with 1~4 females. Intra group correlation of full-sibs was used and Causal components of phenotypic variance were calculated with the GLM procedure of the SPSS software to complete the estimates. The main purpose of the study is to provide theory basis for multi-traits compound breeding and an example for selective breeding of stress-resistance traits. The results are as follows:1. Heritability estimates for body weight and body length of"Huanghai No.1"shrimp (Fenneropenaeus chinensis)Both body weight and body length of offsprings were measured in 3 and 4 months after hatching (n=30). The results indicate that heritabilities in narrow sense for body length are 0.46~ 0.53 and 0.44~0.48 at 3 and 4 months, respectively. Estimates of heritabilities in the narrow sense for body weight are 0.45~0.48 and 0.42~0.43 at 3 and 4 months, respectively. The higher heritabities were found in"Huanghai No.1"shrimp compared to other shrimp species which may be is related to selection intensity. So it is important to combine phenotypic selection with marker assisted selection (MAS) in order to have a good and rapid selection process.2 Heritability estimates of"Huanghai No.1"shrimp (Fenneropenaeus chinensis) for resistance to high pH and high ammoniaTest on the acute toxicity of pH and ammonia were carried out to determine 24h LC50 value and the survival ratios of offsprings were used to estimate the heritabilities for resistance to high pH and high ammonia of"Huanghai No.1"shrimp. The results are as follows: (1) The survival ratios of"Huanghai No.1"shrimp are 34.15% and 26.54% under high pH and high ammonia conditions at 3months, while at 4 months they are 49.27% and 39.46%, respectively. (2) A reduction of heritabilities in the narrow sense for resistance to high pH from 0.29~0.31 at 3 months to 0.26~0.31 at 4 months suggests significant maternal effects are present. In the same way, the heritabilities in the narrow sense for resistance to high ammonia declined from 0.21~0.23 to 0.15~0.22. (3) T test show that the heritabilities of"Huanghai No.1"shrimp obtained from intra group correlation of full-sibs are precise and unbiased for resistance to high pH and high ammonia. (4) With the development of"Huanghai No.1"shrimp smaller heritabilities will be estimated due to less maternal effect and close to the expected value.