Identification Of Molecular Markers For The Excellent Characters Of Hypophthalmichthys Nobilis And Breeding Route Of Shanggao Population

Eleven growth traits,including body mass,full length,body length,head length,snout length,tail stalk length,head height,body height,tail stalk height,body width and head width,were measured in Shanggao and Ruichang Bighead culture populations at 8 months and 20 months of age,respectively.The differences of growth traits and proportional traits(the ratio of length traits to body length)between the two populations were analyzed.Principal component analysis,classification discriminant analysis and path analysis of body mass based on two stage phenotypic traits were carried out based on proportional traits.The results showed that the growth traits of the upper high population at these two growth stages were significantly lower than that of Ruichang population.The results showed that the accurate determination rates of the original group individuals aged 8months and 20 months were 96.6% and 95.9%,respectively.Body height,total length,head length,caudal stalk length and body length played a significant role in determining body weight in 8-month-old fish,and the coefficients of body height and body length on body weight were 0.178 and 0.110,respectively.Body length,body height and head width play a significant role in determining body weight in 20-month-old fish,and the coefficient of determining body height to body weight is the highest 0.456.In conclusion,the growth performance of the high population at these two growth stages was lower than that of the Ruichang population.Subsequently,microsatellite molecular marker technology was used to preliminarily screen out a number of microsatellite loci with polymorphism in the Ruichang population,and finally the polymorphism loci was used to verify in the upper high population and screen the progeny with good traits.100 pairs of primers were developed and designed based on Bighead genome,and24 pairs of primers were obtained from related species for subsequent experiments.Nine microsatellite loci were detected in Ruichang population,and a total of 29 alleles were obtained,with 2-5 alleles amplified by each pair of primers.The number of effective alleles ranged from 1.0317 to 3.3957,with an average of 1.9033.The observed heterozygosity ranged from 0.2712 to 0.9688,with an average value of 0.5916.The expected heterozygosity was 0.0310～0.7129,with an average of 0.3750.SSR polymorphism information content ranged from 0.0399 to 0.7227,with an average value of 0.3924.In the upper high population,9 microsatellite loci were detected,and30 alleles were obtained.2～5 alleles were amplified from each pair of primers.The number of effective alleles ranged from 1.5424 to 4.2013,with an average of 2.087.The observed heterozygosity ranged from 0.1905 to 0.8045,and the mean value was0.5537.The expected heterozygosity was 0.3049～0.8095,with an average of 0.4729.SSR polymorphism information content ranged from 0.3730 to 0.675,with an average value of 0.5166.The results showed that the genetic diversity of these two populations was moderate.Correlation analysis using spss26.0 software showed that among the 9 selected microsatellite markers,there were significant or extremely significant correlations with head length,kiss length,body height,head width,body width,head length/body length,kiss length/body length,and head width/body length,respectively.