| Chinese soft-shelled turtle (Pelodiscus sinensis) is one of premium fishery animals in China, which has high nutritional value and medicinal value. Therefore they are favored by consumers and the aquatic product farmers. With the rapid development of Chinese soft-shelled turtle industry, the germplasm resources of Chinese soft-shelled turtle are under tremendous threat since the 1990s.Although many studies about germplasm conservation and breeding work has been carried out in recent years, but they still cannot be adapted to development speed and scale of the Pelodiscus sinensis.The protection of germplasm resources and breeding for Chinese soft-shelled turtle remains increasingly urgent.We have carried out work on Pelodiscus sinensis breeding with Guangdong LuKa Enterprise CO. With the study of morphological and genetic of different geographic populations, good purebred Yellow River population and Dongting Lake population have been selection. The study of germplasm and breeding were carried out in this paper to provide theoretical basis for protecting germplasm and breeding.1. Growth analysis:To assess the growth of three populations of soft-shelled turtle(Pelodiscus sinensis)in China:Huanghe(HH), Dongting(DT), Lvka(LK) (DT♀ ×HH♂),an experiment in aquaculture performanc was carried. The experiment was started from 1 August 2012 to 15 April 2013. The growth data of the three populations of Pelodiscus sinensis (weight, carapace length, carapace width, plastron length, plastron width, body height, back apron width) were recorded every 30 day period. Results showed that:(1) the order of growth rate was HH>LK>DT;(2) Uniformity, in early stage Luka population was best,the order during young turtle was DT>LK>HH;(3) The back apron width of three populations had no significant difference;(4) bait coefficient:DT<LK< HH;survival rate:DT>LK>HH.These data suggest the growth speed,uniformity,bait coefficient and survival rate of Luka population were between the parents.The conclusion was that the LK showed obvious advantages.2. Correlation analysis of morphometric traits and body weight at different month ages:120 specimens of each month at 1-month-old stage,3-month-old stage(before winter),9-month-old stage(after winter),11-month-old stage and 13-month-old stage were measured respectively in terms of carapace length, carapace width, plastron length, plastron width, body height,back apron width and body weight. Correlation coefficients, path coefficients and determination coefficients of each trait to body weight were calculated through correlation analysis, path analysis and multiple linear regression. The variables that F test of path coefficients showed no significant was eliminated and then the optimal regression equation was established. The results showed that the correlations between morphometric traits and body weight of Pelodiscus sinensis at different month ages reached significant level(P<0.01)and among all traits reached significant level (P<0.05). At 3-month-old stage,9-month-old stage and 13-month-old stage, the trait with strongest direct effect on body weight was carapace length, but that at 1-month-old stage was plastron length, at 11-month-old stage was plastron width. The result of determinant coefficient analysis was consistent with that of path analysis, and the fitness of equations at different stages was good(86.1%～94.0%) besides3-month-old stage (R2=0.835<0.85) Research have shown that the major morphometric traits affecting body weight were different at different month ages, traits for selection should be beconsideredat different stages.This study provided a scientific basis for selective breeding for Pelodiscus sinensis.3. Effects of morphometric traits on body weight of three cultured populations of Pelodiscus sinensis:Body weight and six morphometric traits in three cultured populations of Pelodiscus sinensis were compared using the path analysis and multivariable regression analysis. Results show that the major morphometric traits affecting body weight were significant variations in the three populations. The major morphometric traits that affected body weight of Yellow River population were carapace length and body height, while that of Dongting Lake population were carapace length, carapace width and body height and that of Luka population were plastron length and plastron width. The multiple regression equations were established as y=-801.208+75.656x1+84.630x5 for Yellow River population, y=-504.672+57.146x1+44.990x2-35.820x5 for Dongting Lake population and y=-591.999+53.211x3+48.537x4 for Luka population. The correlation indexes of each population were greater than 0.85.These indicated that the equations were good and the major morphometric traits affecting body weight were found. Research have shown that the major morphometric traits affecting body weight were different in those three cultured populations, so morphometric traits for selection should be considered at different populations. |
PDF Full Text Request