DEVELOPMENT OF A COLD‐TOLERANT POPULATION OF RED TILAPIA THROUGH INTROGRESSIVE HYBRIDIZATION

Abstract

ABSTRACT A population of red tilapia with cold tolerance traits similar to Tilapia aurea has been produced using introgressive breeding techniques, i.e., hybridization (female T. aurea x male red tilapia, heterozyqous for red trait) followed by backcrossing (female T. aurea x F‐1 male, red phenotype). Progeny of the F‐1 backcross, consisting of approximately 50% normal and 50% red phenotype, survived longer under conditions of ambient cooling than either T. aurea or T. mossambica (P < 0.05). There were no differences in cold tolerance between the normal and red phenotypes of the F‐1 backcross population (P > 0.05). Mean lower lethal temperatures for the three groups were: T. aurea (11.6 °C), T. mossambica (13.8 °C), and F‐1 backcross, red and normal phenotypes pooled, 10.0 °C.