Color, growth and maturation in ploidy-manipulated fancy carp

Abstract

Ploidy manipulation was used to examine the effects of triploidizatin and gynogenetic diploidization in fancy carp, a race of Cyprinus carpio. Ultraviolet dosages of at least 9000 erg/mm 2 were required to inactivates sperm genetically. An interval of 10–12 min before the start of 60-min cold treatments was required to retain the second polar body in fertilized eggs. At optimum conditions, survival rates of gynogenetic diploids were 80% to the eyed embryo stage and 25% to hatching; corresponding values in triploids were 73% and 32%, respectively. The highest success rates in inducing gynogenetic diploids and triploids were 100% and 68.9%, respectively. Triploids with the Japanese strain as the female and European strain as the male parent grew slower than control diploids when they were reared in the same pond for 20 months. However, triploids using the Japanese strain as both parents grew larger in 7 months than control diploids. Triploids at 20 months of age had less developed gonads and more fat around the digestive tract than diploid fish. Male-specific color spots were smaller in triploids than in control diploids. The typical red and white fancy carp colors were found in the gynogenetic diploids in almost the same frequency as in the control diploids. Recombination between gene and centromere was observed at the Gpi-2 locus in gynogenetic diploids.