Download - Maize

Strategic Initiative 8. Seeds of discovery:
Opening the “black box” of maize genetic diversity
Value proposition
Foster the targeted mobilization of novel native genetic diversity in breeding programs worldwide by
using advanced technologies to fully catalog the genetic heritage of international maize seed collections,
and to make the resulting information and knowledge freely available—through a user‐friendly, webbased
platform and a marker‐assisted introgression pipeline.
This Initiative has an immense leverage and impact potential. It will enable the entire maize breeding
and research community worldwide to fully utilize the native genetic diversity in the world’s maize
genetic resources, also to accelerate breeding gains and counteract the combined and growing negative
effects of climate change and scarcity of water, land and nutrients. Genetic diversity is an essential
component of breeding progress, and so far the plant breeders have utilized only a minuscule fraction of
this bio‐resource.
Justification
General background
Maize genetic diversity has been assembled and conserved over many decades in seed collections such
as those held by CIMMYT and IITA. This diversity has furnished the building blocks for breeding modern
cultivars. However, only a tiny fraction of the vast genetic diversity of maize collections has been put to
practical use in breeding programs worldwide. The sheer size of the seed collections, as well as
technological limitations, has made comprehensive phenotypic and molecular description of the
collections impossible. This situation is now rapidly changing with the new marker systems, nextgeneration
sequencing and precision phenotyping technologies. Breeders are not only eager for
adequate phenotypic and molecular information about seed collections, but they also need tools for
mining such information and ways for accessing diversity in a more targeted manner. This Strategic
Initiative will comprehensively address these constraints and thus assist breeders in the identification of
useful native diversity and targeting its mobilization into maize breeding programs worldwide.
Why international agricultural research?
CIMMYT and IITA collectively hold 12 the world's most diverse collection of maize diversity, including
nearly 25,000 landraces, teosinte/Tripsacum wild relatives, and 3,000 elite inbreds, pools, and
populations. These collections also serve as intermediaries between “upstream” basic and strategic
research and “downstream” applied maize breeding. The ex situ collections are directly linked to worldclass
plant breeders, agronomists, molecular biologists, and socioeconomists, as well as global
partnerships to apply science for development. The value‐added initiative proposed will be global in
nature and the outputs freely shared to foster their widespread, beneficial use.
Current status of research
Molecular diversity in both natural and elite maize germplasm from several countries has been
extensively analyzed with microsatellite/SSR markers (Prasanna et al. 2010). CIMMYT provided
leadership in analysis of a large collection of tropical/subtropical maize accessions and genetically
heterogeneous landraces, the latter by using a population bulk fingerprinting strategy (Warburton et al.
2008, 2010).
12 As guided by the International Treaty on Plant Genetic Resources for Food and Agriculture (http://www.planttreaty.org).
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