UTILIZATION OF GENOMICS FOR IMPROVING PRODUCTION TRAITS IN COOL AND COLD WATER AQUACULTURE
Location: Cool and Cold Water Aquaculture Research
Title: Mapping of QTL for bacterial cold water disease resistance in rainbow trout
Submitted to: International Symposium on Genetics in Aquaculture
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2012
Publication Date: June 30, 2012
Citation: Palti, Y., Vallejo, R.L., Welch, T.J., Leeds, T.D., Evenhuis, J., Gao, G., Liu, S., Rexroad III, C.E., Wiens, G.D. 2012. Mapping of QTL for bacterial cold water disease resistance in rainbow trout [abstract]. International Symposium on Genetics in Aquaculture. p. 354.
Bacterial cold water disease (BCWD) causes significant economic loss in salmonid aquaculture. We previously detected genetic variation in survival following challenge with Flavobacterium psychrophilum (Fp), the causative agent of BCWD in rainbow trout, and a family-based selection program to improve resistance was initiated at the National Center for Cool and Cold Water Aquaculture (NCCCWA) in 2005. In order to understand the genetic architecture underlying variation in BCWD resistance, we made select crosses in 2007 and 2009 and phenotyped fish using Fp injection challenge. In 2009, fifteen families were created with a predicted F2 or back-cross (BC) segregation of major loci based on full-sib family performance of the grandparents and parents. From each F2/BC family, 200-260 fish were challenged in 4-7 replicates per family. Whole genome QTL scanning of three families with approximately 270 informative microsatellite loci per family spaced at an average interval size smaller than or equal to 10cM along the rainbow trout chromosomes was conducted. Two traits were mapped, Survival Status (dead or alive) on day 22 post challenge and Survival Days. Eight significant (LOD is greater than or equal to 4) QTL and 23 suggestive (LOD is greater than or equal to 3) QTL were identified for the two survival traits. The QTL will be further tested by genotyping of half-sib families and test crosses of fish from this germplasm with un-related germplasm from other rainbow trout broodstocks, including our spleen size QTL mapping population.