Abstract:To explore the growth performance of tetraploid offspring of Pengze crucian carp (Carassius auratus pengsenensis)♀×Xingguo red carp (Cyprinus carpiouar singuonensis)♂,and to explore the development and application prospects of the new Pengze crucian carp variety,the body weight and length data of tetraploid offspring of Pengze crucian carp (PX) and gynogenetic offspring of Pengze carp (PP) at 0,30,60,90,120,150 and 180 d after hatching were taken through the 180 d feeding experiments,and then the growth performance of the two offspring were analyzed. The results showed that during the 180 d experiment,the body weight and body length of PX were significantly different from those of PP. At the end of the experiment,the body weight and body length of PX were 30.18% and 7.70% higher than those of the PP. The absolute weight gain rate of the two groups showed a trend of first increasing,then decreasing and then increasing,reached the maximum at 30-60 d,reached the minimum at 90-120 d,and the difference between them was significant at 0-90 d and 120-180 d (P<0.05).The absolute growth rate showed the same trend,but there was no significant difference between the two groups after 90 d. It was found that the accumulation volume of the two offspring was different except for 90-150 d (P<0.05),and it reached the maximum value of 0.010 5±0.001 2 at 30-60 d. During 30-180 d,the coefficient of fatness of PX was significantly different from that of PP,indicating that the tetraploid offspring were more obese. The growth curve was obtained by fitting the relationship between body weight and body length in different periods,and the growth curve of PX and PP were:W=0.0320L2.991 5(R2=0.977 9), and W=0.0307L2.9941,R2=0.982 7,respectively. To sum up,the hybrid tetraploid offspring of Pengze crucian carp ♀× Xingguo red carp♂show good growth performance,which has the potential of cultivating new variety of Pengze crucian carp and the value of promotion.