Principles of Genetics and Breeding

13.1.7.1.2. Cross breeding in Tilapia

In tilapias very few investigations have been carried out on crossbreeding among different genetic groups of the same species. Most investigations concentrated on interspecific hybrids. Some yield advantage of crossbreds between geographical isolates of T. nilotica over intra isolate spawns is indicated by Guerrero.

Investigations of a similar nature in Israel, involving O. niloticus and O. aureus have not detected any such advantage.

Most strains of red tilapias are based, at least in part, on the genetic determinant(s) of “red” isolated in O. mossambicus. Growth rate of these strains appears to be slow, compared to fast growing species or hybrids, presumably due to the relative slow growth of O. mossambicus. Faster growing, cold tolerant strains of red tilapia have been developed by introgressing the red determinant(s) of O. mossambicus into O. aureus T. After two generations of backcrossing to O. aureus, the resultant red introgression product showed a cold tolerance and growth rate similar to O. aureus.