In traditional backcross breeding, a trait, such as disease resistance, from a donor cultivar is introduced into a cultivar of interest, generally high yielding. Offspring are selected for the introduced trait and crossed back to the high yielding cultivar for multiple generations. The goal is to develop a cultivar identical to the high yielding cultivar with the exception of the introduced disease resistance trait. Backcross breeding takes several generations and for some species many years.
Forward breeding is a type of backcross breeding. Forward breeding takes advantage of improved cultivars and genetic knowledge that may have been developed during the process of backcross breeding. In the case of forward breeding the “best” cultivar of interest is used as the recurrent parent, not the original cultivar of interest, allowing for the inclusion of recent breeding advances into the backcross breeding program. Forward breeding is described in United States Patent Application US20090064358, which you may find in on-line databases (http://www.freepatentsonline.com/20090064358.pdf). Germplasm genotype is often a consideration in forward breeding. Marker assisted selection is particularly useful when selecting for multiple quantitative traits.
Another modification of backcross breeding involves “background selection” or “donor genome elimination”, where the backcross process is accelerated by coupling phenotypic selection with genomic selection for the genetic background of the recurrent parent.
See more on Breeding and Selection.