Selection Evaluation Of F₁, F₂ And F₃ Selected Generations Of Yellow River Populations Of Chinese Soft-shelled Turtle, Trionyx Sinensis

Excepting Tibet,Qinghai and Xinjiang,Chinese soft-shelled turtle(Trionyx sinensis) distributes in various regions of China.And in overseas,it distributes in North Korea, Japan and Vietnam mainly. After the researches of our laboratory,Yellow River population of Chinese soft-shelled turtle shows better economic traits and genetic traits compares with the other geographic populations.The staff of Shaoxing National Chinese soft-shelled turtle Wild Strain Farm has selected the Yellow River population,and three generations have been produced.This study was based on previous work,and was used to evaluate selection effect of F₁,F₂ and F₃ selected generations of Yellow River populations of Chinese soft-shelled turtle. Specific contents are as follows:1. A Comparative Study on Aquaculture Performance Among F₁-3 Selected Generations of Yellow River Populations of Chinese Soft-shelled TurtleA Comparative Study on Breeding Performance was carried out from larvae to adult stage among F₁,F₂ and F₃ selected generations of Yellow River populations of Chinese soft-shelled turtle.The main results were:(1) Daily individual body weight gain: The F₂ and F₃ were higher than the F₁ significantly in larvae stage(p﹤0.01),and the order was F₃≈F₂﹥F₁. The F₃ was higher than the F₁ and F₂ significantly in adult stage(p﹤0.01), and the order was F₃﹥F₂﹥F₁.(2) The daily average yield per square meter: The F₂ and F₃ were higher than the F₁ significantly in larvae stage(p﹤0.01),and the order was F₃﹥F₂﹥F₁. The F₃ was higher than the F₁ and F₂ significantly in adult stage(p﹤0.01), and the order was F₃﹥F₂﹥F₁.(3) The coefficient of variation of body weight: the order was F₁﹥F₂﹥F₃ in larvae stage, and the order was F₂﹥F₁﹥F₃ in adult stage.So the F₃ was growth most orderly.(4) The ratio of skirts: the order was F₃(18.1%)﹥F₂(17.79%)﹥F₁(17.47%)in adult stage. Comprehensive analysis of four traits show that they are improved generation by generation.2. Microsatellite analysis of genetic variation in F₁,F₂ and F₃ selected generations of Yellow River populations of Chinese soft-shelled turtleTo access genetic variations during genetic selection of Chinese soft-shelled turtle (Trionyx sinensis) , the specimens of Chinese soft-shelled turtle , collected from three selected generations (F₁, F₂ and F₃) of Yellow River population as testing group , and their base population (F0) as well as the Taihu population as control group , were amplified by ten pairs of microsatellite primers . The result showed that : (1) A total of 250 alleles were detected in all examined loci . In all five populations the value of average allele number (Na) were 4.60～5.30 , the value of average of effective number of alleles (Ne) were 3.24～3.59 ; the value of average observed heterozygosity (Ho) were 0.4833～0.5300 , the value of average expected heterozygosity (He) were 0.5949～0.6459 and the value of average polymorphism information content (PIC) were 0.5340～0.5684 . (2) The three selected generation's heredity multiple parameter Ho, He and PIC demonstrated reduces identically , along with the increases of Selected generations . It indicated that the mass selection targeted on phenotypes such as growth , body color , body shape , produced a detectable effect on the genetype . (3) The phylogenetic tree showed that studied five populations were clustered into two groups , the first group consisted of the four Yellow River populations while the second group belongs to Taihu Lake population. It indicated that a significant genetic differentiation between Yellow River populations and Taihu Lake population had existed and not been changed by current three generations selection .3. Microsatellite analysis of genetic variation between F₃ selected generations of Yellow River population and Representative populations of major mainland of Chinese soft-shelled turtleMicrosatellite markers were used to observe and analyse the genetic variation between F₃ selected generation of Yellow River population and five representative populations of major mainland of Chinese soft-shelled turtle. The result showed that : (1) A total of 334 alleles were detected in all 14 examined locis. In all six populations the value of average allele number (Na) were 3.6～4.2, the value of average of effective number of alleles (Ne) were 2.53～2.99 ; the value of average observed heterozygosity (Ho) were 0.4714～0.5821 , the value of average expected heterozygosity (He) were 0.5515～0.5997 ; the value of average polymorphism information content (PIC) were 0.4872～0.5406 and the value of average Shannon's Information index (H′) were 1.001～1.106. Six populations of Chinese soft-shelled turtle had relatively higher genetic diversities, and F₃ selected generation of Yellow River population slightly lower than other populations. (2) F-statistics and AMOVA analysis showed that the genetic differentiation between F₃ selected generation of Yellow River population and Yellow River population is not significant(P>0.05) , and the genetic differentiation between F₃ selected generation of Yellow River population and the other four populations is very significant(P<0.01). (3) The phylogenetic tree showed that studied six populations were clustered into three groups. The first group consisted of F₃ selected generation of Yellow River population and Yellow River population.The second group consisted of Poyang Lake population and Dongting Lake population,and the third group consisted of Huaihe River population and Taihu Lake population. (4) Overall, Selection make F₃ selected generation of Yellow River population tend to purified,and this lead to the result that the genetic diversities of F₃ selected generation of Yellow River population slightly lower than other populations.But the historic pattern of biological evolution and regional differentiation of Chinese soft-shelled turtle can not been changed by current three generations selection.The F₃ selected generation of Yellow River population still have relatively higher genetic diversities, and have relatively higher breeding potential.