Abstract:In this study we compared the reproductive performance of female parents, growth of these filial generations, survival, and yield of six inbreeding generations (F1-F6) of full-sib families of Portunus trituberculatus. The statistical methods applied in the study were single factor analysis of variance (One-Way ANOVA), least significant difference (LSD), multiple comparison analysis, and analysis of covariance. We set up the reproduction between two full-sib inbreeding families (F3-F6), Pedigree A (F6) and B (F3), at different genetic purification degree. There are four experimental groups, of which there are two inbreeding groups F66 (A♀×A♂) and F33 (B♀×B♂) and two hybrid groups F63 (A♂×B♀) and F36（B♂×A♀). By comparing the growth of filial generations of four experimental groups during the outdoor periods, we found that at 80-day, 100-day, 120-day and 150-day, different characters of the same hybrid group had different heterosis at the same growth stage, and the same character of the same experimental group also had different heterosis at different growth stages. In inbreeding groups, different characters had the same growth trend as F33 > F66. As for the growth rate, the hybrid groups showed overall heterosis (-3.50% to 19.47%) with different heterosis levels in individual characters. In terms of survival, hybrid groups showed significant heterosis compared to inbred groups with a heterosis rate of 24.8%, and the overall heterosis of 15.99% in the yield associated with survival. Family A benefited more from the hybridization than Family B regarding both the growth characters and the survival, which was consistent with the results of early growth study in the four sub-generation experimental groups. Genetic differences between Family A and B were the basis of potential heterosis and improvements in characters.
