Genotype by sex interaction at different phases during Nile tilapia culture period

Interação genótipo e sexo em diferentes fases do período de cultivo de tilápias do Nilo

ABSTRACT.

Co(variance) components and genetic parameters were estimated for performance and morphometric traits in male and female Nile tilapia at different growth periods to verify the need for separate selection programs for the two genders. Data set contained information on 1,720 animals, collected in cage system. Two-trait analyses using Bayesian methodology were conducted and the records of males and females were considered distinct traits. Rates of additive genetic variance, phenotypic and heritability were higher for females in estimates for morphometric traits and higher for males in performance traits. Whereas common hatchery environment showed higher relative importance for males, the nursery caused greater variations in females. The reduction of the genetic correlation rates caused by growth increased the difference between genders and indicated the treatment of males and females as a distinct feature selection.

Keywords:
Oreochromis niloticus; sexual dimorphism; Bayesian inference