Genetic effects influencing salinity tolerance in six varieties of tilapia (Oreochromis) and their reciprocal crosses

Six tilapia varieties were used in two 6 x 6 diallel crosses. Salinity was increased in daily increments of 7 g L⁻¹ in five replicate trials to estimate the salinity tolerances of 2205 F₁ juveniles from parental varieties and their reciprocal crosses. Genetic effects potentially influencing salinity tolerance were estimated, including line effects, maternal effects, reciprocal and specific reciprocal effects, direct heterosis, specific combining abilities (SCAs) and general combining abilities (GCAs). The mean heterosis, [graphic removed] , for salinity tolerance was 4.46 g L⁻¹ (P