While the average map density exceeds the objectives, six gaps greater than 20cM remain. The gaps may represent physically small regions of high recombination. Physically large regions of low frequency recombination were also observed. The nucleolar organizers, the sites for the 26s and 18s ribosomal RNA genes, have long been known to reside at the secondary constriction on chromosomes 6 and 7. These are located approximately a chromosome arms' length from the centromere on each chromosome.
Nomenclature remains a problem.
In the hope of reducing future confusion, an international committee has been organized to attempt to standardize barley gene map nomenclature. Pat Hayes and Ben Liu reported on quantitative trait analyses performed on replicated field and malt quality data gathered from testing sites in Oregon, Washington, Idaho, and Montana, using software designed by Drs. Ben Liu and Steve Knapp at Oregon State University. The ability of QTL-STAT to handle data from multiple environments and to provide nonlinear estimates of gene effects appeared to be a significant improvement over its predecessors. Major genes that modify yield, quality, and related traits were identified.