A sex-averaged genetic linkage map in coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var 'menziesii') based on RFLP and RAPD markers

We have constructed a sex-averaged genetic linkage map in coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] France var 'menziesii') using a three-generation outcrossed pedigree and molecular markers. Our research objectives are to learn about genome organization and to identify markers associated with adaptive traits. The map reported here is comprised of 141 markers organized into 17 linkage groups and covers 1,062 centiMorgans (cM). Of the markers positioned on the map, 94 were derived from a Douglas-fir complimentary-DNA (cDNA) library that was constructed from new-growth needle tissue. Other markers include 11 Douglas fir genomic-DNAs, 20 loblolly pine (Pinus taeda L.) cDNAs, 15 random amplified polymorphic DNAs (RAPDs) and a PCR-amplified phytochrome probe. A high degree of variation was detected in each of the two parents of our mapping population, and many of the restriction fragment length polymorphism (RFLP) and RAPD phenotypes were complex. Marker data were analyzed for linkage using mapping software JOINMAP version 2.0.