Single gene inheritance of red body coloration in Taiwanese red tilapia

Abstract

Randomly selected red tilapia ( Oreochromis mossambicus×O. niloticus) broodfish were mated in aquaria and small concrete ponds at a ratio of one male to three females. Eggs were collected from individual females and artificially incubated. Body color was examined when the fry were 2 weeks old. A phenotypic ratio of three red to one black colored tilapia was obtained. Results of F2 progeny obtained from crosses of various body color combinations of the F1 progeny showed that red body coloration was inherited as a single gene with incomplete dominance. The study demonstrated that of the six possible matings, pink×pink, pink×red, pink×black, red×red, red×black, and black×black, the first three produce only pink or red tilapia. Thus, it is suggested that RR is the genotype for pink color, Rr for red color, and rr for black color.