SSR Analysis And Gentic Parameter Of Growth Traits In Hucho Taimen

Hucho taimen(Pallas) is a kind of indigenous and endangered cold-water fish in China. Since the problems of artificial propagation and larval fish domestication were solved, its artificial cultivation brings in good economic benefit. However, fry quality and quantity could not be guaranteed due to all artificial breeding parents are derived from wild population without genetically modified. The phenomenon of slow growth, poor resistance and low survival rate are serious. So, It is important for the aquaculture of Hucho taimen developed steadily and healthily by breed up an good variety with high growth rate and low disease incidence. In this study, genetic parameter, one single marker QTL and hybrid incompatibility of Hucho taimen were discussed to provide important data for selective breeding.Nine half-dam families and 34 fu11-sib families were established by nest design using one female parent mated to four male parents. Nineteen of 34 fu11-sib families were raise under 11~14℃while others were under 8~10℃. Variance components of phenotypic variance under different period were calculated with the GLM procedure of the SPSS software. The estimate of narrow-sense heritability were 0.413~0.675 for body weight and 0.297~0.777 for body length under low temperature, while 0.396~0.558 and 0.194~0.624 for body weight and body length respectively under high temperature, all of them were relatively high. Variance components between female parents were larger than variance components between male parents for each growth trait, indicate that large maternal effect or other non-additive genetic effects exist, and heritability estimate from variance components between male parents were relatively unbiased. The estimate of narrow-sense heritability under high temperature were larger than low temperature, suggesting that G×E interaction exist and phenotypic selection could respond favorably under low temperature. Genetic and phenotypic correlation of body weight and body length was significant under different temperature and period (P<0.01), the estimate of genetic and phenotypic correlation were 0.815~0.939 and 0.794~0.939, respectively. Relatively high heritability estimates and positive genetic correlations indicate that growth traits of Hucho taimen could improved favorably either through selection on body weight or body length.12 polymorphic EST-SSR markers were developed from its cDNA library by (CA)16 probe. The EST-SSRs and other 32 genomic SSRs were used to one single marker QTL analysis of growth traits in Hucho taimen. Result showed five markers were significantly related to growth traits, which is of great important for molecular assisted selective breeding. Intergeneric hybridizations of Hucho taimen(♂) and Brachymystax lenok(♀) were produced in this study. The results showed phenomenon of hybrid incompatibility such as low larval floating rate and high deformity rate. 30 microsatellite primers were used for genetic analysis on relationship between F1 hybrids and their parents. The results are as follows: 1) twenty-five pairs of mocrosatellite primers showed specific bands on both parents, 2 pairs showed specific bands only on H. taimen while 3 pairs only on B. lenok; 2) All bands of microsatellite locus came from parents except one F1 hybrid on locus Omi84TUF, the inherited character of 21 locus completely follows the Mendelian rule indicated that the hybridization between the parents are gamogenesis and most genetic material come from both of the parents; 3) Four locus Omi105TUF, Omi156TUF , Omi165TUF and Omy16DIAS showed doubled maternal bands or no paternal specific bands on some F1 hybrids, this may be caused by abnormality in process of pairing or separation for some chromosomes, which may result in hybrid incompatibility; 4) The genetic similarity and genetic distance between F1 hybrids and H. taimen were 0.6735 and 0.3953 respectively, the genetic similarity and genetic distance between F1 hybrids and B. lenok was 0.7298 and 0.3150 respectively, the results showed F1 hybrids had more closer relationship with B. lenok. It was also supported by UPGMA clustering.We provide important data for selective breeding such as genetic parameter and EST-SSR marker, and we also reasonablely explain the phenomena of hybrid incompatibility. Above all, all achievement of this study is of great meaning for the selective breeding.