Harnessing Maize Biodiversity

Abstract

The phenotypic and genetic diversity of maize worldwide is remarkable. This chapter summarizes decades of studies of the genetic diversity of maize populations from different parts of the world, methods used to group maize into informal hierarchies, and how these groupings partition genetic and trait variation. The USA is the most important maize-producing nation, but the genetic diversity of USA maize is small relative to the available worldwide variation. Tropical maize harbors more genetic variation, but is not adapted to growing in temperate environments. Two distinct approaches to tapping the global reservoir of maize diversity to improve USA and other temperate region maize crops are outlined. One approach, allele mining, involves discovery of alleles with large favorable effects on traits in exotic germplasm, followed by marker-aided backcrossing or gene editing to introduce specific unique alleles into elite breeding populations. Alternatively, for traits conditioned mostly by many small-effect polygenes, rapid genomic selection for adaptation followed by combining ability within pure exotic populations could be used to create adapted and improved versions of exotic populations before they are crossed to elite adapted inbreds to make new breeding populations.

The original version of this chapter was revised: For detailed information please see correction. The correction to this chapter is available at https://doi.org/10.1007/978-3-319-97427-9_22