ARS | Publication request: GENETICS AND GENOMICS - INTEGRATION OF MOLECULAR GENETICS INTO A BREEDING PROGRAM FOR RAINBOW TROUT

Submitted to: Israeli Journal of Aquaculture
Publication Type: Proceedings/Symposium
Publication Acceptance Date: June 30, 2006
Publication Date: December 1, 2006
Citation: Silverstein, J., Weber, G.M., Rexroad III, C.E., Vallejo, R.L. 2006. Genetics and genomics - integration of molecular genetics into a breeding program for rainbow trout. Israeli Journal of Aquaculture 2006. 58:231.

Technical Abstract: At the National Center for Cool and Cold Water Aquaculture (US Department of Agriculture, Ag. Research Service) in Leetown, WV, we have a broodstock development program now entering the 2nd generation of family based selective breeding using expected breeding values (EBVs). Our major breeding objectives are faster growth and resistance to Flavobacterium psychrophilum, the causative agent of bacterial coldwater disease. For these traits we have developed assays to evaluate phenotypic performance. In addition to our breeding program, we are participating in an international collaboration, to develop a microsatellite marker linkage map for the rainbow trout with the intent of identifying QTL¿s and using them in marker or gene assisted selection (MAS or GAS). There are several possible approaches to take with regard to the types and numbers of markers to develop, and the strategies and methods for implementing the markers in a selective breeding program. This paper describes the choices we have made concerning QTL identification for traits of high, low and unknown degrees of heritability. These traits are plasma cortisol response to a crowding stress (h2@ 0.4), feed intake (h2@ 0.1) and resistance to Flavobacterium psychrophilum (h2 between 0.1 and 0.2). In order to identify QTLs in a relevant commercially important rainbow trout line we are making crosses from within our resource population. The development of research family crosses, choice of markers for genome scanning, and planned steps to implementation of these results are described.