Crop breeding

How are plants bred to be biofortified? Why is it important?

The plants in our diet are critical to our health. Food crops provide us with nutrients important to human health, growth, and metabolism. Different vegetable crops contain many types of vitamins and minerals that are the basis of a healthy diet. For example, carrots are high in beta-carotene, but have good amounts of Vitamins K and B1. If we don’t get a good mix of vegetable and fruit choices, our diet isn’t as healthy as it can be. This imbalance of nutrients can lead to disorders or diseases.

sweet potatoes raw and cut

Sweet potatoes have been biofortified to contain more pro-Vitamin A, to help with malnutrition. Credit: Sunette Laurie, Agricultural Research Council, South Africa

It is thought that food is the best medicine for its contribution of nutrients, importance in preventing disease, and availability to the general public. Although it might seem that to fight malnutrition, taking a multi-vitamin (or specific vitamin supplements), and distributing vitamins to those in need can have complications. And, often, the food source of a vitamin or mineral is better absorbed than a supplement.

Governments and public health organizations have responded to malnutrition by developing fortification programs. These programs add purified nutrients to commonly consumed foods.  For example, in the U.S., milk is fortified with Vitamin D. We also commonly fortify breakfast cereals with iron, and add iodine to salt. Adding vitamins and minerals to commonly eaten foods can be a good way to prevent nutrient deficiencies.

Fortification programs can have limitations. They require substantial coordination between public health workers, governments, and private food companies. It can be difficult to get fortified foods to consumers within food systems impacted by difficult infrastructure and weather. In addition, fortified foods must be distributed for the long-term, with continuous investments.

Fortified foods have nutrients added to food after harvest, usually during processing. Scientists wondered if they could breed plants to accumulate specific nutrients. This produces biofortified foods. Biofortification is the effort to develop new food crop varieties with higher amounts of micronutrients. The improved food starts with the seeds sown into the field. This allows communities and farmers to grow their own biofortified food product. They can also retain seeds from this year’s crop for next year.

farmer with rice

Rice supplies 65% of Cambodian’s caloric intake! Biofortifying the rice plant with various nutrients can help improve nutritional quality of this important staple crop. Credit: Joshua Nasielski

Biofortification is an important part of global food security as an agricultural solution to public health. There are several strategies to fortify plants with micronutrients: by land (soil), by sea (water), and through genetics. Biofortification by soil and water uses the ability of plants to accumulate nutrients with higher soil concentrations. For example, changes in the soil pH, mineral content, and soil microbes can change how much micronutrients end up in the food. The same can occur through water. The mineral content of a plant’s water supply can increase minerals in the food. However, biofortifying through soil and water is a more local solution. Field conditions from one location to another can be very different.

BioFortifiedFood

Fortified foods have nutrients added during processing. Biofortified crops are bred to take in more nutrients from the soil – and make the crops more nutritious. Credit: ASA/CSSA staff

The most promising method of biofortification is through genetics. Breeders research the development of a new type of crop that retains all of the good qualities of the parent plants. The goal is to retain the high yield, disease resistance and good taste of a crop – while increasing nutrient value.

In traditional crop breeding, breeders mate (“cross”) two varieties of a food crop to improve traits for farmers and consumers. The plants with “elite” traits, like high yield, disease resistance and good taste, are crossed with ones that accumulate more nutrients. This process is repeated through many growing seasons until they develop a new variety that is both elite and accumulates more micronutrients.

An important aspect of biofortification is that it can be applied to many crops. This fits the traditions and tastes of local communities. For a population like India, breeders might work on high-iron millet, a common food in that country. In Uganda, high pro-vitamin A sweet potatoes are reducing malnutrition. And, in sub-Saharan Africa, where beans are a staple food, breeders worked to develop high-iron beans. A recent report found that such programs have provided biofortified foods to more than 20 million people [1]!

A limitation to the traditional breeding method is that it requires finding a variety that is high in a target nutrient to cross with the elite variety. For example, there is a need to biofortify rice with beta-carotene (pro-vitamin A). Malnutrition in Vitamin A can lead to eye problems, and even blindness. Distributing Vitamin A supplements can be difficult, and many go without the amount they need to be healthy.

It is very hard to use traditional breeding to improve pro-vitamin A levels in the rice grain. Rice tends to accumulate the pro-vitamin A in its inedible leaves versus the actual grain. Therefore an effort was developed to biofortify rice grain with pro-vitamin A by adding in the missing genetics to the seed. Scientists were able to use genes from corn plants, which naturally develop high amounts of pro-vitamin A. The resulting biofortified food is known as Golden Rice (www.goldenrice.org).

Crop breeders and scientists continue to learn more about how plants acquire, synthesize, and store micronutrients for our foods. Future goals include quickening the pace of breeding to bring more biofortified crops to market. It will also be important to continue to establish these crops as a regular part of the global food system.

Answered by Adam Heuberger, Colorado State University

To read more about biofortification pioneer Howarth Bouis, read this story: https://dl.sciencesocieties.org/publications/csa/articles/61/12/20 

  1. Bouis, Howarth E., and Amy Saltzman. “Improving nutrition through biofortification: A review of evidence from HarvestPlus, 2003 through 2016.” Global food security12 (2017): 49-58.

About us: This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.

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