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Commercial QPM seed is currently available in all collaborating countries and, based on average 2003–
2005 seed production, approximately 200,000 hectares are being planted to QPM cultivars and in some
instances nutritional impacts quantified (Gunaratna et al., 2010). A number of national programs across
Latin America, Africa, and Asia have released QPM hybrids and OPVs, utilizing the QPM germplasm
developed by CIMMYT and IITA (Prasanna et al. 2001; Krivanek et al. 2007; Atlin et al. 2010).
Since 2004 both CIMMYT and IITA have conducted maize research under HarvestPlus at . The primary
focus of HarvestPlus‐Maize research is identification and development of tropical germplasm as source
of pro‐VA and development of high‐pro‐VA hybrids and OPVs. As a secondary objective, the program has
identified maize varieties with high zinc concentrations. Maximum pro‐VA concentrations between 6
and 8 ppm have been validated in germplasm in development. Breeding for enhanced pro‐VA has
reached an advanced stage, and experimental hybrids have been produced at both IITA and CIMMYT
and evaluated by the Zambian Agricultural Research Institute, SeedCo, and ZamSeed, key partners of
HarvestPlus.
Research on carotenoid retention during handling and processing is also conducted at CIMMYT and IITA.
Research on recurrent selection as a strategy to develop OPVs with increased pro‐VA concentration has
demonstrated an increase of at least 1 ppm for each cycle of selection. OPVs for enhanced pro‐VA are
being developed by conversion of commonly used OPVs or by formation of new varieties. All breeding
efforts in this SI will include not only the evaluation for stress (mainly drought and low nitrogen) and
higher potential environments but also the conversion of the best drought and low nitrogen tolerant
elite lines to enhanced VA.
Recently, CIMMYT scientists in collaboration with the University of Illinois, Cornell University, the
National Maize Improvement Center of China, China Agricultural University, and Michigan State
University identified two genes (LycE and Crt‐RB1) in the carotenoid biosynthetic pathway with major
effect on VA concentrations (Harjes et al. 2008; Yan et al. 2010). Molecular markers for assaying
functional polymorphisms within these two genes have been developed and validated across diverse
genetic backgrounds; these are being used in the CIMMYT pro‐VA breeding program and hold great
potential for national breeding programs. In addition to protein quality and micronutrient traits, several
other nutritionally significant traits such as low phytate content (Raboy et al. 2000 ) and high vitamin E,
ascorbate, and folate contents (Naqvi et al. 2009) have been discovered, but these require more
detailed studies before proceeding to breed germplasm with nutritional efficacy.
The long experience of CIMMYT and IITA on QPM holds many important lessons that can be applied to
other biofortification efforts. Successful development and adoption can only occur when there is
assurance of competitive agronomic performance of the nutritionally enhanced germplasm, easily
accessible screening tools for breeding and quality control, effective seed production systems, economic
benefits and market incentives for producers, and strong partnerships with national research programs
and health and agricultural ministries (Atlin et al. 2010). Biofortification strategies must include both
breeding and improved agronomy practices, as micronutrients like zinc are highly dependent on both
soil quality and farming practices.
Biofortification interventions have a long‐term impact on the nutritional status of the populations most
in need of them, and most of the nutritional compounds are invisible to the farmers. However, based on
the QPM experience, one of the most effective ways to promote the adoption of such cultivars in
countries where maize is the staple crop is to focus on the development and dissemination of low‐cost
biofortified OPVs that are agronomically superior to local landraces. This could likely be achieved in
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