The Breeding Of Ornamental Oviparous Killifish By Space Mutation

The experimental material was fertilized eggs of killifish (Nothobranchius Guentheri) which some were carried into space by Shenzhou VII spacecraft and the other were preserved on earth, the eggs were incubated and cultivated. In this study, we observed the difference of hatching rate of eggs, larvae abnormality, fry survival and growth rate of fry between the space group and the ground control group. The comparison rearing were be done continuously 5 generation between the two groups killifish, the difference of body size , fecundity and egg fertilization rate were observed. We revealed the fecundity difference between different families of space group or ground control group,the selective breeding were done to the larger fecundity families of space group. The influence of fecundity and fertilization rate of killifish by difference of water temperature and mating pattern of male and female fish were observed also. The major research contents of this dissertation included:1. The difference of hatching rate of fertilized eggs and larvae abnormality are no significance between space group and ground control group. The growth rate and body size of space group male fish were larger than the ground control group, the difference was significant (p﹤0.05).The fry survival rate of space group was higher than the ground control group(p﹤0.05).2. After 5 generations comparison rearing, the results showed that the body size of F₁,F₂ space group male fish were larger than the ground control group, the difference was significant (p﹤0.05),but there was no significant difference of male fish body size between F₃,F₄,F₅ of space group and ground control group, respectively. There was no significant difference of female fish body size between F1 to F5 of space group and F1 to F5 of ground control group(pï¹¥0.05); the fecundity of the space group was larger than the ground control group(p﹤0.05),but the difference of fertilization rate of eggs were no significance(pï¹¥0.05).3. The fecundity difference between different families of space group or ground control group was significant (p﹤0.05), and the difference among families of space group was larger than ground control group.4. The daily fecundity and fertilization rate of killifish were higher under 26℃temperature condition,26℃is the best temperature to Nothobranchius Guentheri reproduction. When the mating pattern were 4♂+1♀,2♂+1♀and 1♂+ 1♀the daily fecundity were higher, and the fertilization rate of which were higher too, 4♂+1♀,2♂+1♀and 1♂+1♀were the best mating pattern to Nothobranchius Guentheri production.