ABSTRACT
A North American two-row barley mapping dataset was used to demonstrate quantitative trait loci (QTL) mapping with genotype main effect and genotype–by-environment (GGE) biplot. We demonstrate that biplots can give correct clusters of markers that are known to be closely linked and that they provide similar linear arrangements of markers within clusters of markers in each of the seven barley chromosomes. We also demonstrate that GGEbiplot provides a convenient means for identifying QTL for a target trait. QTL mapping using a biplot takes a different approach from interval mapping but achieves the same results and is much simpler. Besides, the GGE biplot approach provides information about the trait and marker values of individuals in the mapping population, which directly leads to marker-based selection. The biplot pattern also allows missing marker data to be replaced with considerable accuracy. Finally, QTL-by-environment interaction and marker-based selection are discussed.
