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With research staff from more than 60 countries, and offices across the globe, IFPRI provides research-based policy solutions to sustainably reduce poverty and end hunger and malnutrition in developing countries.

Erick Boy

researcher spotlight

Erick Boy

Erick Boy is the Chief Nutritionist in the HarvestPlus section of the Innovation Policy and Scaling Unit. As head of nutrition for the HarvestPlus Program since 2008, he has led research that has generated scientific evidence on biofortified staple crops as efficacious and effective interventions to help address iron, vitamin A, and zinc deficiency in sub-Saharan Africa, Latin America, and South Asia.

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Since 1975, IFPRI’s research has been informing policies and development programs to improve food security, nutrition, and livelihoods around the world.

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IFPRI currently has more than 600 employees working in over 80 countries with a wide range of local, national, and international partners.

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The University of California (UC) Davis College of Agricultural and Environmental Education is dedicated to preparing graduates to address the challenges in the field of agriculture. UC Davis teaches students such topics as sustainable agriculture and environmental systems. The program emphasizes real-world activities and hands-on training for students.

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Publications

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Working Paper

Parametric and machine learning approaches to examine yield differences between control and treatment considering outliers and statistical biases: The case of insect resistant/herbicide tolerant (IR/HT) maize in Honduras

2025Falck-Zepeda, José B.; Zambrano, Patricia; Sanders, Arie; Trabanino, Carlos Rogelio
Details

Parametric and machine learning approaches to examine yield differences between control and treatment considering outliers and statistical biases: The case of insect resistant/herbicide tolerant (IR/HT) maize in Honduras

Robust impact assessment methods need credible yield, costs, and other production performance parameter estimates. Sample data issues and the realities of producer heterogeneity and markets, including endogeneity, simultaneity, and outliers can affect such parameters. Methods have continued to evolve that may address data issues identified in the earlier literature examining genetically modified (GM) crops impacts especially those of conventional field level surveys. These methods may themselves have limitations, introduce trade-offs, and may not always be successful in addressing such issues. Experimental methods such as randomized control trials have been proposed to address several control treatment data issues, but these may not be suitable for every situation and issue and may be more expensive and complex than conventional field surveys. Furthermore, experimental methods may induce the unfortunate outcome of crowding-out impact assessors from low- and middle-income countries. The continued search for alternatives that help address conventional survey shortcomings remains critical. Previously, existing assessment methods were applied to the impact assessment of insect resistant and herbicide tolerant maize adoption in Honduras in 2008 and 2012. Results from assessments identified endogeneity issues such as self-selection and simultaneity concurrently with influential outliers. Procedures used to address these issues independently showed trade-offs between addressing endogeneity and outliers. Thus, the need to identify methods that address both issues simultaneously, minimizing as much as possible the impact of method trade-offs, continues. We structured this paper as follows. First, we review the literature to delineate data and assessment issues potentially affecting robust performance indicators such as yields and costs differentials. Second, we discuss and apply four types of approaches that can be used to obtain robust performance estimates for yield and cost differentials including: 1) Robust Instrumental Variables, 2) Instrumental Variable Regressions, and 3) Control/Treatment, and 4) Machine Learning methods that are amenable to robust strategies to deal with outliers including Random Forest and a Stacking regression approach that allows for a number of “base learners” in order to examine the pooled 2008 and 2012 Honduras field surveys. Third, we discuss implications for impact assessment results and implementation limitations especially in low- and middle-income countries. We further discuss and draw some conclusions regarding methodological issues for consideration by impact assessors and stakeholders.

Year published

2025

Authors

Falck-Zepeda, José B.; Zambrano, Patricia; Sanders, Arie; Trabanino, Carlos Rogelio

Citation

Falck-Zepeda, José B.; Zambrano, Patricia; Sanders, Arie; and Trabanino, Carlos Rogelio. 2025. Parametric and machine learning approaches to examine yield differences between control and treatment considering outliers and statistical biases: The case of insect resistant/herbicide tolerant (IR/HT) maize in Honduras. IFPRI Discussion Paper 2334. Washington, DC: International Food Policy Research Institute. https://hdl.handle.net/10568/174327

Country/Region

Honduras

Keywords

Latin America and the Caribbean; Central America; Maize; Yields; Impact Assessment; Agriculture; Data; Capacity Building; Machine Learning; Parametric Programming; Herbicide Resistance

Language

English

Access/Licence

Open Access

Source

Source record

Record type

Working Paper

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Journal Article

Combining GWAS and TWAS to identify candidate causal genes for tocochromanol levels in maize grain

2022
Wu, Di; Li, Xiaowei; Tanaka, Ryokei; Wood, Joshua C.; Tibbs-Cortes, Laura E.; Magallanes-Lundback, Maria; Bornowski, Nolan; Hamilton, John P.; Vaillancourt, Brieanne; Diepenbrock, Christine H.
…more Li, Xianran; Deason, Nicholas T.; Schoenbaum, Gregory R.; Yu, Jianming; Buell, C. Robin; DellaPenna, Dean; Gore, Michael A.
Details

Combining GWAS and TWAS to identify candidate causal genes for tocochromanol levels in maize grain

Tocochromanols (tocopherols and tocotrienols, collectively vitamin E) are lipid-soluble antioxidants important for both plant fitness and human health. The main dietary sources of vitamin E are seed oils that often accumulate high levels of tocopherol isoforms with lower vitamin E activity. The tocochromanol biosynthetic pathway is conserved across plant species but an integrated view of the genes and mechanisms underlying natural variation of tocochromanol levels in seed of most cereal crops remains limited. To address this issue, we utilized the high mapping resolution of the maize Ames panel of ∼1,500 inbred lines scored with 12.2 million single-nucleotide polymorphisms to generate metabolomic (mature grain tocochromanols) and transcriptomic (developing grain) data sets for genetic mapping. By combining results from genome- and transcriptome-wide association studies, we identified a total of 13 candidate causal gene loci, including 5 that had not been previously associated with maize grain tocochromanols: 4 biosynthetic genes (arodeH2 paralog, dxs1, vte5, and vte7) and a plastid S-adenosyl methionine transporter (samt1). Expression quantitative trait locus (eQTL) mapping of these 13 gene loci revealed that they are predominantly regulated by cis-eQTL. Through a joint statistical analysis, we implicated cis-acting variants as responsible for colocalized eQTL and GWAS association signals. Our multiomics approach provided increased statistical power and mapping resolution to enable a detailed characterization of the genetic and regulatory architecture underlying tocochromanol accumulation in maize grain and provided insights for ongoing biofortification efforts to breed and/or engineer vitamin E and antioxidant levels in maize and other cereals.

Year published

2022

Authors

Wu, Di; Li, Xiaowei; Tanaka, Ryokei; Wood, Joshua C.; Tibbs-Cortes, Laura E.; Magallanes-Lundback, Maria; Bornowski, Nolan; Hamilton, John P.; Vaillancourt, Brieanne; Diepenbrock, Christine H.; Li, Xianran; Deason, Nicholas T.; Schoenbaum, Gregory R.; Yu, Jianming; Buell, C. Robin; DellaPenna, Dean; Gore, Michael A.

Citation

Wu, Di; Li, Xiaowei; Tanaka, Ryokei; Wood, Joshua C.; Tibbs-Cortes, Laura E.; Magallanes-Lundback, Maria; et al. 2022. Combining GWAS and TWAS to identify candidate causal genes for tocochromanol levels in maize grain. Genetics 221(4): iyac091. https://doi.org/10.1093/genetics/iyac091

Keywords

Maize; Health; Genes; Biofortification; Vitamin E

Language

English

Access/Licence

Open AccessCC-BY-NC-ND-4.0

Source

Source record

Record type

Journal Article

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Book

Agricultural R&D in the developing world: too little, too late?

2006Pardey, Philip G.; Alston, Julian M.; Piggot, Roley R.
Details

Agricultural R&D in the developing world: too little, too late?

The purpose of this volume is to document the changing institutions and investments in agricultural R&D in less-developed countries, in part to form a companion volume to Paying for Agricultural Productivity by providing a more complete global picture of the issues. A more important purpose is to take stock of what is happening in less-developed countries. This task is especially compelling if, as seems likely, these countries will have to become more self-reliant in developing crucial new agricultural technologies… The chapters document the history and current status of the national agricultural research systems (NARSs) in terms of policies, institutions, investments, and achievements. The case studies cover a geographically dispersed area (South Africa and China, for example) and diverse farming systems (such as Brazil vs. Korea), yet some common themes emerge… This book has been written primarily for those who make policy and allocate resources for agricultural research and extension, and the policy analysts and development specialists who advise them: specifically, strategic decision makers and their advisers in international agencies, national governments, and public or private agricultural research and extension organizations.

Year published

2006

Authors

Pardey, Philip G.; Alston, Julian M.; Piggot, Roley R.

Citation

Pardey, Philip G.; Alston, Julian M.; Piggot, Roley R., (eds). 2006. Agricultural R&D in the developing world: too little, too late? Washington, DC: International Food Policy Research Institute (IFPRI). https://doi.org/10.2499/089629756XAGRD.

Country/Region

Bangladesh; Brazil; Colombia; China; Korea, Republic of; India; Indonesia; South Africa; Zambia

Keywords

Asia; Africa; Eastern Asia; Southern Asia; Sub-saharan Africa; Agricultural Research; Developing Countries; Agricultural Technology; National Agricultural Research Systems; Policies; Development

Language

English

Access/Licence

Open Access

Links

https://doi.org/10.2499/089629756xagrd Source record

Record type

Book

Events

CGIAR Platform for Big Data in Agriculture Convention
IFPRI at External Event

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October 3 to 5, 2018

CGIAR Platform for Big Data in Agriculture Convention

IFPRI Staff are participating in the CGIAR Platform for Big Data in Agriculture co-hosted by the International Center for Tropical Agriculture (CIAT) taking place October 3-5, 2018 at the Campus of the World Agroforestry Center (ICRAF) in Nairobi, Kenya. This convention is the second yearly event to bring together the people and organizations that make the […]