Induced All-Female Autotriploidy in the Allotetraploids of Carassius auratus red var. (♀) × Megalobrama amblycephala (♂).

Following activation by UV-irradiated BSB sperm, the fertilized eggs of tetraploid hybrids (abbreviated as 4nF1) (4n = 148, AABB) of Carassius auratus red var. (abbreviated as RCC) (2n = 100, AA) (♀) × Megalobrama amblycephala (abbreviated as BSB) (2n = 48, BB) (♂) developed into normal live gynogenetic offspring without chromosome doubling treatment. Some of these were autotriploids with three sets of red crucian carp chromosomes (abbreviated as G1) (3n = 150, AAA). G1 were all-females, and can produce unreduced (3n) eggs at age 1 year. After activation by UV-irradiated BSB sperm, the fertilized eggs of G1 developed into a second generation of autotriploid gynogenetic offspring (abbreviated as G2) (3n = 150) without chromosome doubling treatment. G1 were obviously different from both 4nF1 and RCC in their morphological traits and showed a significantly higher growth rate than RCC. In aquaculture, the autotriploid fish could provide an important source of gametes for the production of all-female triploid fish and for the establishment of autotriploid gynogenetic lines.