Abstract

In salmonids, spawning date is an important productive and life-history trait determining the time of fertilization, date of progeny emergence, and even the probability of survival and the growth rate of the small fry. Recent evidences support a polygenic basis with several Quantitative Trait Loci (QTL) affecting the phenotypic expression of this trait in salmon species. Utilizing females from two populations of Coho salmon (Oncorhynchus kisutch) obtained by divergent selection for early and late spawning date, we have identified three RAPD markers amplified with primers UBC-075, UBC-229 and UBC-249 associated with spawning date. Polymorphic fragments were characterized and converted in two codominant and one dominant SCAR PCRbased marker Oki075 (AY926350), OkiCAT229UCH (AY926352) and Oki249 (AY929856). The SCARs Oki075 and Oki249 have been mapped at different chromosomes using FISH. We identified a 52 bp repetitive motif minisatellite like on marker Oki075 and a microsatellite di-nucleotide TG/AC motif on marker OkiCAT229UCH. These three SCAR markers show significant association with spawning date in Coho salmon, however it was not possible to discard a genetic drift effect, therefore more study is necessary to verify the associations presented here.