Plant & Animal Genome VI Conference

W28

GENETIC MAP CONSTRUCTION WITH AFLP MARKERS IN LOBLOLLY PINE

Forest Biotechnology Group, Department of Forestry, North Carolina State University, Raleigh, NC 27695-8008

We have generated nearly 500 polymorphic AFLP markers for a linkage map in an elite loblolly pine (Pinus taeda L.) family, using only 21 primer pairs. Our goal is to use this information to map QTLs and viability loci in self families. The large size of the pine genome (1n=2x10¹⁰ bp in Pinus taeda) poses special challenges for using the AFLP marker system because of the large number of bands generated per primer pair. We have successfully overcome this problem by using Eco+2/Mse+2 primer combinations for preamplification and Eco+3/Mse+4 combinations for the selective amplification. Paradoxically, further increases in the number of selective nucleotides can result in an increase in fragment number, presumably because the small proportion of mismatch products are amplified to the point of visibility. We generated AFLP fragments using fluorescently-labeled primers, which were analyzed on a Li-Cor automated sequencer. Specialized software facilitates scoring of the digital images, and the resulting reports are easily converted to Mapmaker format for generating maps. Results of linkage map construction, strategies for increasing the usefulness of dominant markers for QTL mapping in F₂ or self families, and opportunities to integrate the positive features of various marker types, will be discussed.