Crops

It all Starts with a Seed

At HarvestPlus, it all starts with a seed. Conventional plant breeding and modern technology can increase the density of micronutrients in staple crops grown and consumed by smallholder farmers around the world. This means that tens of millions of people today, many having suffered from the effects of ‘hidden hunger’, are eating more nutritious foods—vitamin A cassava, vitamin A maize, vitamin A orange sweet potato, iron beans, iron pearl millet, zinc rice, and zinc wheat—and improving their health.

The biofortification process begins with a seed that is viewed through a multidisciplinary lens. Agricultural experts, nutritionists, public health specialists and consumer marketing experts look at that seed as the first step in the biofortification process. Biofortification is successful only when plant breeders can develop those traits that meet not only the nutritional needs—increased density of micronutrients—but also other requirements of the consumers—such as taste, color, cooking time, to name a few—and agricultural needs—such as higher yield and climate smart—of the farmers.

Iron, Zinc and Vitamin A: Triumvirate for Good Health

HarvestPlus focuses on three micronutrients: Iron (Fe), zinc (Zn) and vitamin A. Iron deficiency during childhood and adolescence impairs mental development and learning capacity. In adults, it reduces the ability to do physical labor. Severe anemia increases the risk of women dying in childbirth. Zinc is involved in more body functions than any other mineral.

Zinc’s role includes acting as a necessary component of more than 200 enzyme systems, normal growth and development, the maintenance of body tissues, sexual function, vision, and the immune system. Zinc is essential for survival, and zinc deficiency has serious consequences for health, particularly during childhood when zinc requirements are increased. In addition, zinc deficiency also causes stunting. Randomized controlled trials showed that zinc supplementation can reduce the severity of morbidity from a number of common childhood infections, including diarrhea, pneumonia, and possibly malaria, by one-third. 

Vitamin A is essential for good vision and cell differentiation. Deficiency results in growth retardation, damage to mucous membrane tracts, reproductive disorders, eye damage—and ultimately blindness. Children with vitamin A deficiency are often deficient in multiple micronutrients and are likely to be anemic, have impaired growth, and be at increased risk of severe morbidity from common childhood infections such as diarrheal diseases and measles. Pregnant women with vitamin A deficiency may be at increased risk of mortality.

Nutritionists are the first of our multidisciplinary team to begin work on the biofortification process. They determine the target levels of these important micronutrients that are needed to make a measureable impact on the human body. Nutritionists look at such variables as bioconversion and bioavailability of ingested nutrients; micronutrient losses during storage and processing; micronutrient requirements for good health; and potential levels of consumption by the target population. Targets were set such that, for preschool children 4–6 years old and for non-pregnant, non-lactating women of reproductive age: the total amount of iron in iron beans and iron pearl millet will provide approximately 60 percent of the Estimated Average Requirement (EAR); zinc in zinc wheat and zinc rice will provide 60–80 percent of the EAR; and provitamin A, the precursor of vitamin A, will provide 50 percent of the vitamin A EAR in the case of yellow cassava and orange maize, and up to 100 percent in the case of orange sweet potato (OSP). It is nutrition that drives the process of biofortification.

The seed is then studied through the lens of socio-economics. Farmers and consumers must accept the new crop for biofortification to work. Acceptance depends on developing attractive trait packages without compromising agronomic and end-use characteristics, such as color or taste. Prior to the final release of a new biofortified crop, HarvestPlus conducts a variety of ex-ante impact assessments, including marketing, consumer and behavior change studies.

The challenge in biofortification is putting together all pieces of the puzzle to create a micronutrient-rich crop that is acceptable to both farmers and consumers. The product must have the right amount of micronutrient to have a positive impact on health. For the farmer, the crop must have attractive agronomic properties, such as high yield, tolerance to major pests and diseases and climate-resistance to make it worth his effort to grow. For the consumer, quality traits such as taste and color must be acceptable.

Making a Better Seed: How We Do It

Plant breeding is the genetic improvement of the crop in order to develop new varieties with desirable characters (traits)—higher yield, resistance to diseases, better nutrition (higher micronutrient content). We do this in collaboration with international research institutes and national research partners  in target countries.

The first step in developing a biofortified crop  is to screen existing crop varieties and accessions readily available in global germplasm collections, to evaluate the genetic diversity and identify plants with the desirable characters.

The source of genetic variation is important for the next steps in breeding:

  • Pre-breeding is required if micronutrient variation is discovered in the strategic genepool. This means that the materials are usually non-adapted (exotic or semi-exotic), but their desirable traits can be used in crosses, genetic studies, molecular marker development and parent-building.

  • If micronutrient variation is present in the tactical genepool, the materials may be used directly to develop the new varieties. In this case, parent lines with high vitamin or mineral levels are crossed over several generations to produce plants that have the desired micronutrient content as well as other traits important for acceptance by farmers and consumers.

The next step is to thoroughly test the newly selected, micronutrient-dense lines in experimental stations and farmers’ fields. The plants are evaluated for their yield and other agronomic traits including tolerance to major pests and diseases. These evaluations are done in comparison to the best available local cultivars. The influence of varying climatic and soil conditions is also studied, as well as performance under different agronomic management practices (fertilizer application, irrigation, etc.). Seeds of the best-performing materials are then multiplied and made available as public goods to national governments, which officially release the new crop varieties and make them available to farmers.

Today, biofortified crops, including provitamin A-rich orange sweet potato, iron beans, iron pearl millet, provitamin A yellow cassava, provitamin A orange maize, zinc rice, and zinc wheat, have been released in more than 30 countries and are being tested and grown in more than 40 countries. Crop improvement continues to develop varieties with higher levels of vitamins and minerals that are adapted to a wide range of agro-ecological conditions, and ensuring that the best germplasm for climate-adaptive and consumer-preferred traits continues to be used in breeding biofortified crops.

HARVESTPLUS IMPACT PATHWAY

 
The challenge in biofortification is putting together all of the pieces of the puzzle to create a micronutrient-rich crop that is acceptable to both farmers and consumers.
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