Download - Maize

Breeding programs will achieve more effective design of “cisgenics”, informed by new insights into
gene functions, derived from comprehensive marker‐trait association studies.
Key milestones
2011: Business plan and terms of engagement developed for research partners.
2011: Global Maize Phenotyping Network formed; priority traits, methods, research partners, and
accessions to be characterized agreed upon. Decisions taken about which databases, seed bank
management systems and web portals to build upon, and on the kind of IT expertise required to
implement the SI. Legal and publicity arrangements for creating a pre‐competitive “Commons”
domain for data delivery validated by legal and public‐relations experts. Genomic selection (GS)
initiated in at least five pre‐breeding populations to sample under‐utilized maize races.
2012: Raw, simple version of the database behind the future web portal available and ready to accept
molecular and trait data streams (milestone shared with WHEAT SI 8 on Opening the “blackbox”
of wheat genetic diversity). CIMMYT‐ and IITA‐held maize collections meet best‐practice
standards, as recognized by QMS or other certifications. 13
2013: Ultra‐high‐density SNP genome‐profiles (10 5 –10 6 loci) for most accessions (five individuals per
population) generated via GBS and uploaded to database. At least 40 (candidate) genes of known
functions sequenced across trait‐dependent core sets, with sequenced genes matching targeted
traits. Marker‐assisted introgression pipeline established and working for a number of priority
cases. First, simple version of the MAIZE Diversity Portal available to provide CRP members with
on‐line access to data streams (output shared with WHEAT SI 8). Compatible seed bank
management systems deployed (milestone shared with WHEAT SI 8).
2014: Evaluation completed of approximately 40 key agronomic, nutritional/grain quality and
abiotic/biotic stress‐related traits across trait‐dependent core sets. A second set of varieties,
selected on the basis of molecular data, added to the sets. Twenty years of trait data from field
trials of participating seed banks and breeding programs uploaded. Set of priority traits reevaluated
and adjusted.
2015: Genomes of a set of thoroughly phenotyped accessions fully or partially re‐sequenced (e.g., via
exon‐capture or skim‐sequencing). Fully refined version of the MAIZE Diversity Portal completed
and on‐line. Critical diversity gaps filled in CIMMYT‐ and IITA‐held ex situ maize collections.
2016: Field trials for second‐series core sets/traits completed. Novel favorable alleles and haplotypes
identified by SI members and uploaded to the MAIZE Diversity Portal. Network of data miners
adding value to the MAIZE Diversity Portal established. MAIZE Diversity Portal cross‐links with
other on‐line resources such as GeneSys, MaizeGDB, GenBank and the Patent Lens. Elite prebreeding
populations sampling underutilized maize races derived from at least four cycles of GS
made available to breeders.
What's new in this initiative?
This SI is the first attempt to comprehensively characterize the inherent heritage of one of mankind’s
three major cereal crops. The goal is to produce a world‐first, breeder/researcher‐friendly “catalog” for
the CIMMYT‐ and IITA‐held maize seed “libraries”. The SI, however, will go well beyond a simple stocktaking
of diversity, to promote flow of useful diversity into research and breeding programs, not only via
well‐characterized accession seeds but also by capturing into elite backgrounds both large‐effect QTL
alleles via marker‐assisted introgression and small‐effect alleles via rapid‐cycle genomic selection.
13 Excellence Through Stewardship certification (http://www.excellencethroughstewardship.org).
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