Prospects for genetic technology in salmon breeding programmes

Selective breeding has been very successful in increasing production in Atlantic salmon. Gene technology opens new opportunities to comprehend the nature of the genetic variation underlying production traits. Two major areas in which gene technology may play an important role are (1) production of genetically modified fish and (2) development and utilization of genetic markers. Several studies of transgenic salmonids have shown substantially increased growth rates. However, many different issues are related to whether genetically modified fish should be used or not. Genetic markers can be used for aquaculture purposes and for monitoring wild populations. Construction of genetic maps based on markers enables the identification of quantitative trait loci (QTL) and/or markers linked to them. This will facilitate marker‐assisted selection, enabling improvement in economically important traits, in particular traits difficult to breed for, such as food conversion efficiency and disease resistance. Several experiments aimed at mapping QTL in salmonids using genetic markers are ongoing. DNA marker technologies can also be used for identification and monitoring of lines, families and individuals, and for genetic improvement through selection for favourable genes and gene combinations.