Exploitation of Elite Maize (Zea mays L.) Germplasm across Maturity Zones

Abstract

Transfer of elite lines across maturity zones is important because it facilitates the exploitation of indirect selection gain. The main goal of this study was to investigate strategies to guide the transfer of elite lines from Southern Europe to the U.S. Corn Belt. Testcrosses of progenies of six biparental populations derived from a diallel cross of four Southern European elite lines were evaluated together with adapted commercial checks in 10 Southern European and six U.S. Corn Belt environments in 2007 for grain yield and grain moisture when crossed to adapted testers. Moreover, the 788 genotypes were fingerprinted with 857 single nucleotide polymorphism (SNP) markers and multiple‐line cross quantitative trait locus (QTL) mapping was performed. Some testcross progenies in the U.S. Corn Belt reached grain yield performance comparable to the best check, which suggests that direct use of Southern European lines is promising. The success of using grain yield or grain moisture data determined in Southern Europe to preselect Southern European lines for use in the U.S. Corn Belt is limited. Moreover, we observed a complex genetic architecture of adaptation with absence of major QTL and strong QTL by background interactions. We found evidence that epistasis influences adaptation, additionally hampering the success of marker‐guided transfer of germplasm from Southern Europe to the U.S. Corn Belt.

Ex-situ conservation of maize germplasm from different latitudes

“…When multiplying allochthonous varieties, we should expect changes in some adaptation-related traits, such as flowering time or grain moisture (Peña-Asín et al 2013). Steinhoff et al (2012) concluded that it is possible to use some genotypes from southern Europe for breeding in the USA, but the election of genotypes cannot rely on data determined in Southern Europe because gene × genetic background interactions and epistasis effects affect the morphological variability of genotypes. Therefore, there are effects of environmental adaptation on both the phenotypic and the genetic structure when genotypes are used in environments different to their original locations (Revilla et al 2005).…”