Depts. of Ecology and Evolutionary Biology, Molecular and Cellular Biology, Animal Science, Plant Science, Epidemiology and Biostatistics, University of Arizona, Tucson AZ 85721. jbwalsh@u.arizona.edu
While animal breeders largely focus on improvement using additive genetic variance, inbreeding and asexual reproduction allow plant breeders to at least partially exploit non additive genetic variance as well. We briefly review various approaches used by breeders to exploit dominance and epistatic variance, discuss their constraints and limitations, and examine what (if anything) can be done to improve our ability to further use often untapped genetic variation.