Product Line 2.6. Healthier rice varieties
Among the major micronutrient problems common in rice-consuming countries, the following are highly prevalent: iron, zinc, and vitamin A deficiencies. It is estimated that more than 3 billion people in the developing world are iron-deficient. Almost 3 million children of preschool age have visible eye damage owing to vitamin A deficiency. Estimates of subclinical prevalence of vitamin A deficiency range from 100 to 250 million people. Billions of people are at risk for zinc deficiency. The cost of these deficiencies in terms of lives and quality of life lost is enormous. Current rice varieties do not provide enough micronutrients for leading healthy productive lives. Since rice is the dominant cereal crop in most Asian countries and is the staple food for more than half of the world’s population, even a small increase in micronutrient content in rice grains would have a significant impact on human health. Moreover, biofortification—breeding staples with high micronutrient content—has evolved as a new strategy to address micronutrient malnutrition. Biofortification is likely to reach rural households, as the improvements are targeted to the crops and foods that can be grown and sourced locally and they are expected to have impact in a sustainable manner.
Research in product line 2.6 will be done in collaboration with a wide range of partners and it includes participation of IRRI, AfricaRice, and CIAT in HarvestPlus and associated MP Health and Nutrition activities. However, since the biofortification breeding work is closely tied into mainstream gene discovery and rice breeding work, it is executed in GRiSP as its primary home. Outputs of this research may be cross-listed in GRiSP and MP Health & Nutrition.
2.6.1. Pro Vitamin A-enriched rice (Golden Rice)
The carotenoid locus from the leading GR2 event is being introgressed into mega-varieties of rice popular in South and Southeast Asia in the first phase, using modified marker-aided backcrossing. In addition, the event is also being backcrossed into germplasm preferred in areas with high incidence of vitamin A deficiency. In parallel, communication of the nutrition and health benefits of GR to farmers and consumers to drive adoption and consumption will be undertaken. The communication content will be based on known bioavailablity data and on bioefficacy data to be determined before wide-scale promotion and will be linked to consumers’ understanding of nutrition and health.
2.6.2. High-Zn rice
High-yielding varieties possessing enhanced grain zinc content will be developed. Ample genetic diversity in the cultivated germplasm for grain zinc content exists, and the best donor parents will be crossed with high-yielding indica elite lines, whereas superior recombinants will be selected using newly developed high-throughput screening methods. The initial launch country will be Bangladesh, which is establishing a support network for this launch. In addition, the bioavailability study of Zn from higher-Zn rice is nearing completion; this result will be used in consumer acceptance/promotion studies.
2.6.3. High-Fe rice
High-yielding varieties possessing enhanced grain iron content will be developed. We do recognize that limited genetic diversity in the cultivated germplasm for grain iron content exists. However, the best individual donor parents, separately and together, will be crossed with high-yielding indica elite lines, whereas superior recombinants will be selected using newly developed high-throughput screening methods. The project benefits from knowledge of the bioavailability result for Fe from higher-Fe rice already determined and from synergies with the high-Zn project. Efforts will be made to evaluate the lead/gene promoter combinations from collaborators to raise grain Fe content in transgenic rice to the HarvestPlus target and above. In the following phase, the identified lead events will be transferred into mega-varieties/elite breeding lines. In parallel, high-Fe benefits will be communicated to farmers and consumers to drive adoption and consumption.
2.6.4. Rice with enhanced folic acid
Women with folate deficiency are more likely to give birth to low-birth-weight and premature infants and infants with neural tube defects. A deficiency of folate occurs when dietary intake of folate is inadequate. This is a worldwide problem and some foods are required to be fortified, such as wheat flour. Rice contains little or no folate (B9). Major breakthroughs have been made in recent years in transgenic rice expressing significant levels of folate. These laboratories in Europe and Australia would be collaborators in the project to develop high-folate rice for developing countries. Activities include evaluating existing fol+ events from ARI collaborators, optimizing gene promoter combinations to maximize folate production and retention in rice grain, and evaluating lead events across diverse genetic backgrounds.
The next users are rice breeders working in GRiSP, the private sector, and NARES. Intermediate users are seed producers and distributors, including the public sector, private companies, and NGOs, and final users are farmers. It is assumed that there will be assured funding from donors and national governments to produce and deliver the required amount of seed to farmers. Government policies should facilitate the release of nutritious rice cultivars. INGER, CSISA, and IRRC will play a key role to disseminate and link improved germplasm with appropriate management practices and cropping systems. Germplasm sources should be available from theme 1, and management practices for unfavorable and favorable areas will be developed in theme 3, requiring close linkage. Seed production and dissemination will be handled by linkage with theme 6 and the seed systems in the target countries. Linkage with nationally and internationally funded development projects will facilitate the delivery of improved varieties to farmers. This phase of the project will also benefit from the experiences from the release, production, dissemination, promotion, and uptake of “specialty” rice varieties developed under the BMGF-STRASA project and its successors.
The research is currently funded by HarvestPlus, USAID, the Bill & Melinda Gates Foundation, Rockefeller Foundation, and CIDA. However, additional funding will be required, including co-investments from CRP 4 on Health & Nutrition in this product line on healthier rice varieties.