Mapping of quantitative trait loci controlling adaptive traits in coastal Douglas-fir. I. Timing of vegetative bud flush

Thirty three unique quantitative trait loci (QSLs) affecting the timing of spring bud flush have been identified in an intraspecific mapping populatio n of coastal Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco var. menzies ii]. Both terminal and lateral bud flush were measured over a 3-year period on clonal replicates at two test sites, allowing for the repeated estimati on of QTLs. QTLs were detected on 12 linkage groups and, in general, each e xplained a small proportion of the total phenotypic variance and were addit ive in effect. Several QTLs influence the timing of bud flush over multiple years, supporting earlier evidence that the timing of bud flush through de velopmental stages is under moderate to strong genetic control by the same suite of genes through developmental stages. However, only a few QTLs contr olling the timing of bud flush were detected at both test sites, suggesting that geographic location plays a major role in the phenology of spring gro wth. A small number of QTLs with year and site interactions were also estim ated.