Hybridization in fishes; reasons, applications and detection methods

Hybridization is an important breeding method for obtaining new varieties that increase genetic diversity. Inter-specific hybrids have been produced for aquaculture and stocking programs to increase growth rate, transfer desirable traits between species, combine desirable traits of two parents into a single group. The aim of hybridization in the aquaculture industry is to improve the performance of hybrids compared to their parents under specific environmental conditions. Improvement in production performance in different traits is quite coincidental due to the presence of allelic interaction in hybrids which can provide hybrid vigor or heterosis. Until now, numerous hybrids of fish have been produced naturally or by direct human intervention. Hybrids constitute a significant proportion of some countries’ production for certain taxa. Hybridization has been used in combination with polyploidization to improve developmental stability in hybrid progeny. The results of inter-specific hybridization can be variable and depend on the genetic structure (including the sex) of the parent fish. Detection of hybrid nature of the progeny has a key role in the hybridization practices. Different methods can be used to investigate the true nature of hybrids, such as molecular methods which provide us the possibility to test at early larval stages or even after larval hatching. High precision and accuracy as well as suitable performance test speed make them efficient tools for hybrid detection. Hybridization between different species of food as well as ornamental fish with emphasizing on most important Iranian fish species have been reviewed.