Genetic Parameters Of Growth And Survival For The Selective Breeding Population In Litopenaeus Vannamei

Litopenaeus vannamei, with wide temperature adaptability, strong resistance disease, fastgrowth, low protein content of feed demand for intensive farming,etc, is the most aquacultureproduction of shrimp variety in the world, recently. In recent years, domestic and foreignscholars had detail and outstanding studys on breeding, culture, nutrition, and resistance,however,L.vannamei does not belong to indigeous species and no distribution in our natural sea. Shrimpaquaculture production had been severely restricted due to the serious recession of speciesquality, waht’s more, irregular breeding models and bad managements made destruction andpollution of aquaculture water environment and multiply shrimp bacteria, so to establish a stableand secure and efficient breeding models and cultivate high quality disease resistance andadaptability variety have become a major issue to be resolved.In this paper, we assessed the survival and growth rate and harvest weight of shrimp indifferent regions. Test the performance of each family at the temperature18℃and28℃andestimate the genetic parameters and genotype environment interaction of body length，weightand survival. Measure the meat measurements of shrimp cultured at18℃temperature andanalyze the genetic correlations with other measurements. The results follows below:1. The survival rates of shrimps have no significant difference between different regions andmodels, while growth rates and harvest weight have a significant differences.The survivalrate and growth rate are both negatively correlated with the harvest weight.The correlationcoefficients of growth rate, survival rate and harvest weight are0.300,-0.122and0.186,respectively, statictical tests are not significant(P>0.05). The growth performance of the samefamily varies in different regions, showed that specific test and corresponding breeding planis needed to different areas.5excellent performances of survival rate and harvest weightfamilys were selected based on phenotype.2. The estimates of body length heritability at different temperatures were0.12±0.04and0.07±0.03, respectively, while the estimates of harvest weight heritability at differenttemperatures were0.15±0.05and0.06±0.03, respectively, all belong to the lowheritability(h2<0.15), but survival were0.29±0.08and0.20±0.07, respectively, which belongto medium heritability. Z-score test of the heritability shows significant differences in bodylength and harvest weight(Z≥1.96), but no significant differences in survival at differenttemperatures(Z<1.96). The heritability values estimated based on females lower than males.Survival and weight of L.vannamei had an low linear positive correlation at bothtemperatures, the coefficient was0.102and0.175, respectively. The genetic correlation ofbody length, weight and survival of L.vannamei at different temperatures were0.999,0.899and0.865, respectively. The K values of body length, weight and survival were0,0.20and0.09, respectively, indicating that both effect of genotype and environment interaction weresmall, and had no significant statistical tests(K<0.5). Breeding was not required established aseparate group of core population. 3. The meat measurement(MR) and heritability of L.vannamei at low temperature were52%and0.12±0.04, respectively. The heritability estimates of first abdominal segmentwidth(FASW), first abdominal segment length(FASL), carapace length(CL), abdominalsegment total length(ASL), body length(BL), first abdominal segment height(FASH), bodyweight(BW) and meat weight(MW) were0.23±0.06,0.12±0.04,0.12±0.04,0.16±0.05,0.09±0.04,0.38±0.09,0.07±0.03and0.09±0.04, respectively. FASW has the mostgenetic correlation with MR, which the coefficient was0.44±0.20.we estimates the genetic parameters of L.vannamei at different temperatures, indicating thatit’s practicable and potential to low temperature resistant varieties breeding without separate,The meat measurement can be as an indicator for low temperature breeding. The results of thisstudy can provide basic data for breeding of new varieties resistant to low temperature.