Abstract:This study conducted diallel hybridization experiments on three excellent populations of Procambarus clarkii, namely Gehu, Jiangsu; Jianhu, Jiangsu; and Wuhu, Anhui, with high genetic diversity and fast growth. Six hybrid groups were obtained[Gehu ♀×Jianhu ♂ (GJ), Jianhu ♀×Gehu ♂ (JG), Gehu ♀×Wuhu ♂ (GW), Wuhu ♀×Gehu ♂ (WG), Jianhu ♀×Wuhu ♂ (JW), Wuhu ♀×Jianhu ♂ (WJ)], and three self crossing groups[Gehu ♀×Gehu ♂ (GG), Jianhu ♀×Jianhu ♂ (JJ), Wuhu ♀×Wuhu ♂ (WW)]. A comparative analysis was conducted on the growth performance and ecological adaptability of 9 combinations. The results showed that:(1) During the breeding cycle, the weight gain and weight gain rate of both male and female individuals in the WW and JJ combinations were significantly higher than those in the other combinations (P<0.05); Except for GJ and JG, the weight gain and growth rate of male individuals in all combinations were significantly higher than those in females. From March to May, no heterosis was observed in the growth traits of each hybrid group; (2) With the increase of breeding time, there were significant changes in the length/body length of the head and chest armor, as well as the length/body length of the abdomen in the 9 populations of crayfish. The length/body length of the head and chest armor gradually increased, while the length/body length of the abdomen gradually decreased. In May, there was differentiation between male and female individuals, and the proportion of female abdomen length was significantly higher than that of male. The ratio of head to chest armor width/body length, abdominal width/body length, and tail segment length/body length only showed a significant increase in April; (3) After 24 hours of dry dew, each group of shrimp began to die, and at 48 hours, the survival rate of each group showed significant differentiation. At 48 hours, the survival rate of the WW combination was significantly higher than that of the other combinations. The GJ and JG cross groups showed heterosis in terms of dry dew tolerance. This study found that the mixed germplasm of crayfish limited the heterosis of growth traits to a certain extent, but showed heterosis in stress resistance. Proper hybridization and re-selection are important breeding strategies. The growth and abdominal length ratio of crayfish showed obvious male and female dimorphism, and single sex breeding is also an important direction for future research.