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Institutional weaknesses affecting the maize seed value chain in stress‐prone environments and the
feasibility of alternative seed production and dissemination approaches (OPVs, conventional and
unconventional hybrids) to reach farmers in stress‐prone areas that are less attractive to the private
seed sector.
The effects of predicted climate changes on pathogen and insect pest dynamics and their
agricultural impacts. The effects of changing cropping systems, such as the rice–maize rotation, and
increased adoption of zero tillage/conservation agriculture on disease and pest dynamics.
Outputs
1. Germplasm tolerant to drought, low nitrogen stress, acidity, waterlogging and heat stress that yields
well under favorable conditions and has the necessary biotic stress resistance—for major maize
production regions in Africa, Asia, and Latin America affected by these stresses. This will include:
Donors conferring high levels of abiotic stress tolerance for use in breeding locally adapted
hybrids and OPVs.
Donors conferring high levels of resistance to key biotic stresses, particularly MSV, GLS, E.
turcicum, H maydis, and Striga.
Hybrids and OPVs yielding at least 100% more than current varieties. 10
Hybrids and OPVs with tolerance to combinations of abiotic stresses—in particular heat plus
drought and waterlogging plus drought.
Inbred lines targeted at more favorable production regions, where sporadic droughts (>10% risk
of crop failure) can wipe out significant production volumes and lead to income variation for
farmers, country‐level shortages, and price variations which affect poor consumers.
Our strategy for inbred line development supports both hybrid and OPV production. Inbred lines—
the principal products of CIMMYT and IITA pedigree breeding programs—are the building blocks of
both hybrids and open‐pollinated synthetic varieties 11 . Programs targeting stress‐prone
environments will thus produce hybrids for dissemination by seed companies and OPVs, which are
primarily distributed by government seed units and NGOs, according to local demand and
preference. The formation of synthetic varieties from elite inbred lines adds little to the total cost of
breeding programs, and generates OPVs that are usually more productive than broad‐based
populations.
2. Innovative, low‐cost hybrid seed production systems, involving crosses between narrow‐based
synthetics, between a synthetic and an inbred parent and between advanced marker‐assisted
recurrent selection (MARS) populations derived from high‐yielding, proven double crosses. These
low‐cost, seed‐production approaches will allow small seed companies to produce highly‐vigorous,
heterotic hybrids without the need to produce large amounts of seed of inbred lines, which can be a
long and expensive process that becomes an important obstacle to hybrid seed production.
3. Internet‐based information systems that identify the best available germplasm for various client
groups, including breeders (seeking breeding germplasm from international agricultural research
centers), seed producers (seeking stress‐tolerant, finished varieties from national and international
research systems), and governmental and non‐governmental organizations (seeking seed producers
of drought‐tolerant varieties for seed relief).
4. Open‐source breeding networks and a set of decentralized phenotyping sites to improve maize for
tolerance to drought, nitrogen stress, and heat, using state‐of‐the‐art phenotyping, doubled
10 Currently sown varieties typically yield 1 ton per hectare or less under severe abiotic stress conditions, and in many instances
fail.
11 Synthetic varieties are OPVs produced by initially intermating inbred lines, then maintaining and increasing the variety via
open pollination.
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