Research Of Pyramiding Of Growth-related Genotypes In Largemouth Bass (Micropterus Salmoides)

Largemouth bass, the common name for Micropterus salmoides, belongs to Perciformes, Porcoidei, Cehtrachidae, Micropterus. The main way of breeding at present is selecting artificially: the traditional way of breeding is based on phenotypic selection, but itcan not reflect samples’ genotype really, and the application of molecularmarker-assisted selection for gene pyramiding breeding have not be seen. Genepyramiding breeding is a method of multiple genes by hybridization and selection ofpolymerization in the same material, in order to achieve the purpose of genetic’simprovement. This technology has been developed and applied in crop and livestockand poultry, but a similar report in the fish is rarely to see.Selected from the laboratory has received a number of growth-associated molecularmarkers, Among them, there were eight molecular markers closely related to growth offish closely, such as sites of single nucleotide polymorphism located in IGF-I, POU1F1,PSSIII and MSTN gene and sites of microsatellite: JZL60, JZL67, MisaTpw76andMisaTpw117. Using the technology of STR genotyping, distribution of number ofdominant genotype analysis of selected and growth associated markers in largemouthbass (Micropterus salmoides) new variety "YouLu No.1" generations of breeding.Polymerization for the advantage of the traditional breeding process in genotype;correlation analysis of largemouth bass advantage reproduction genotypes enrichmentquantity and growth traits, explore the application of a growth advantage genotypefeasibility polymerization breeding. STR genotyping technique is a technologyexperiment of distinguished by capillary electrophoresis fragment size, determine thegenotypes of individual. This study provides theory basis for the growth traits of genepyramiding.1. Pyramiding of growth-related genotypes in generations of the largemouth bass (Micropterus salmoides),“Youlu No.1”Using eight molecular markers associated with growth traits of largemouth basswhich were obtained by our laboratory, genotypes of thirty test fishes among differentbreeding generations of largemouth bass "YouLu No.1" were detected and STRgenotype distribution analysis were conducted. Then statistical analysis of the dominantgenotypes in each generation was conducted. Results showed that the number ofadvantage genotypes is0~6in the tested fishes. The average number is2.12,2.70,2.90and3.08in F2, F3, F5and F6generations respectively, presenting a trend of increasingby generation.140largemouth bass "YouLu No.1" and same number of non breedinglargemouth bass were detected. Results showed that average number of dominantgenotypes of "YouLu No.1" was2.606and that of non breeding largemouth bass was2.312. Number of dominant genotypes of the selection group is higher than that of thebreeding population. The results above show with breeding generations progressive,number of largemouth bass dominant genotypes were synchronous increasing trend.This means that the artificial selection has polymerized the advantage genotype to someextent. The result of this research will provide guidance for gene pyramiding breedingof growth related markers.2. Association of pyramiding of growth-related genotypes in largemouth bass(Micropterus salmoides)Four hundred largemouth bass Selected from different farms. Detecting the numberof dominant genotype in each individual by eight molecular markers which related withthe growth trait closely, Choose largemouth bass20tail who contains4or more than4dominant genotypes, wherein the female9, male11tails for population reproduction,Cultivates fries in cement pond After the eggs have been hatched. Randomly selectedtails of5000and reared in1114㎡pond when fishes at the age of two mouths.Randomly collected288tails for measured weight after the fishes grows nine mouths,using technology of STR Genotyping to detect the quantitative of advantage genotypesin offspring. Results showed that the number of advantage genotypes is1~6in the offspring, the body weight is110~410g. The number of dominant genotype2or3ofthe population accounted for the largest proportion, respectively:34.72%and38.19%.The number of dominant gene from largemouth bass population average weight of1-6were:227.83g,239.56g,258.81g,273.02g,302.50g and305.60g, more advantagegenotypes, more excellent growth phenotypic traits. The number of dominant genotypeis related to the growth rate positively. The dominant genotype groups were associatedwith the analysis of the remaining population weight showed: the average weight of thegroups which has dominant genotype higher than the other groups in each locus. Themaximum difference is in weight of MSTN gene, for14.60%, the differences of otherloci for0~12.76%. The dominant genotype on MSTN has larger contribution to theweight. The result of this research could provide guidance for gene pyramidingbreeding.