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11.1.4 Crossbreeding
Crossbreeding is a breeding programme that tries to find mating combinations between different populations of fish which produce superior offspring for grow-out, offspring that are said to exhibit hybrid vigour. Although crossbreeding is a method of increasing yields, the results of crossbreeding programmes are impossible to predict (unless the mating have been made previously), so the production of superior offspring is a hit-or-miss proposition. Many combinations often have to be evaluated before one is discovered that produces offspring with hybrid vigour. Crossbreeding programmes usually involve different strains within a species (intraspecific hybridization), but different species can also be hybridized (interspecific hybridization). To date, much of the breeding work in aquaculture has been devoted to hybridization among the different species of tilapia in an attempt to produce all-male hybrids for grow out. |