The new variety of Fenneropenaeus chinensis “Huanghai No.2”

Two cultured populations of “Huanghai No. 1” variety and “Jikang 98” strain and four wild populations (the south coast of the Korean Peninsula population, Rushan Bay population, Qingdao coast population and Haizhou Bay population ) of F. chinensis were selected as base population via unbalanced nested breeding design in 2005. The multi-traits composite selection method was designed and applied for shrimp F．chinensis genetic breeding program, and three goal traits for growth rate, survival time and survivorship in resistance to White Spot Syndrome Virus (WSSV) were estimated. In order to efficiently decrease the influence of environmental differences on genetic variance, the larvae were breeded by standardised process during the constructing of the families. All pedigreed shrimps were fluorescence-tagged when they reached a body length of 3 cm. These shrimps were tagged with a unique family code by injecting different colors of “Visible Implant Fluorescent Elastomers” (VIE) before being stocked in one grow-out pond. The same number of marked shrimps were chosen from every family and randomly divided into two groups. The group cultured in the same pond was used to estimate the growth rate and survival rate, and the other group cultured in closed cement pit was infected WSSV artificially, which was used to test survivorship in resistance to WSSV later. The estimated results of genetic parameters also show that, the heritabilities of the shrimps were 0.22 for body weight at 170d, 0.14 for survivorship in resistance to WSSV, 0.03 for survival time. According to the information obtained from estimating the breeding value of individuals using BLUP method and the method of percentage weight, the group was selected on an index weighted 80% for growth rate, 15% for WSSV resistance and 5% for survival rate. In addition the breeding values (BV) were standardized, and then aggregate selection index was obtained. The next generation of families was selected to produce based on Selection index values. According to the information of Pedigree, the best mating arrangement was designed and increasing numbers of inbreeding coefficient was lower than 0.01. After four generations of selection, statistical results show that, the genetic gains of each generation on average were 13.56% for growth rate, 6.76% for disease-resistant and 5.05% for survival rate. It was revealed that the heritability of body weight was highest and with the maximal weight, in addition, the genetic gain of each generation was steadily above 12%. However, the heritability of survivorship in resistance to WSSV and survival rate were lower relatively，and the genetic gain of each generation was less and unstable. As the first F．chinensis new variety with multi-traits (better growth performance, higher survival rate and longer survival time after WSSV infection) for extensively farming in China, “Huanghai No.2” was approved by China National Aquaculture Variety Approval Committee as a new variety for aquaculture in 2009. In order to produce new disease-resistance shrimp variety, solve the viral disease of shrimp farming, it was necessary to find out the genetic mechanism of disease-resistant and improve the selection intensity of resistance-disease.