The formation of tetraploid stocks of red crucian carp x common carp hybrids as an effect of interspecific hybridization

F3-F8 hybrids of red crucian carp (Carassius auratus red var.) (female) x common carp (Cyprinus carpio L.) (male) were found to be allotetraploids by examining the numbers and karyotypes of chromosomes, the DNA content of red blood cells, and the mean nuclear erythrocyte volumes. It is concluded that the females and males of F2 hybrids were able to produce, respectively, diploid eggs and diploid spermatozoa and they fertilized to form tetraploid fish.