Bridging conventional breeding and genomics for a more sustainable wheat production

Conventional breeding has a long history of success, while the field of genomics and its applications offer new ways to more efficiently breed new cultivars. In this chapter, using wheat (Triticum spp.) as an example, we review the current understanding of wheat breeding and two of its key aspects: The use and creation of genetic diversity (intercrossing elite lines or crossing elite lines with unadapted lines or wild species; creating mutations; and inserting transgenes), and the ability to phenotypically or genetically select for useful combinations of alleles to create improved lines. The strengths of conventional breeding and genomic -assisted breeding are described, as are their limitations, and how a modern breeding program will adapt and integrate new breeding tools with proven methods. The introduction of new alleles into a population will require estimates of their breeding values and epistasis before they can be effectively selected using genomic selection. Similarly, the importance of genotype- by environment interactions will require extensive field testing and more sophisticating genomic selection models to identify lines for the target set of environments.