Although cassava is virtually unknown in the United States, it is Africa’s most important food crop. Approximately one-third of sub-Saharan Africans rely on cassava for over 50% of their daily caloric intake.  Cassava grows well in marginal soils, producing edible roots that can serve as a family’s staple food or a source of market income. For many Africans, cassava is a source of food security. When other crops are lost to drought, families can turn to their fields of drought-resistant cassava for sustenance.

However, every year 30% of the harvest (on average) is destroyed by Cassava mosaic disease (CMD). This disease significantly harms the food security of millions of Africans throughout the continent. Although significant amount of research has been undertaken to identify sources of resistance to CMD, the varieties developed through classical plant breeding do not protect against the disease in many of the preferred cassava varieties.

Biotechnology offers a promising approach to address the problem of CMD. Transgenic plants developed at the Danforth Center have demonstrated strong resistance to this disease in greenhouse trials over multiple years.

Through four separately funded projects, the Danforth Center is working to develop and deliver disease-resistant cassava to Africa:

BioCassava Plus

The Danforth Center is part of a larger consortium, led by Ohio State University, participating in the BioCassava Plus research project. This project is funded by the Gates Grand Challenges in Global Health Initiative and aims to develop and deliver to Africa a cassava plant with enhanced levels of micronutrients, vitamins, and resistance to environmental stresses.

Modern biotechnology will be utilized to enhance cassava for increased accumulation of (1) bioavailable zinc and iron, (2) high quality protein in the storage roots and (3) vitamin A and vitamin E. In addition, biotechnology will also be used for improved resistance to 4) viral disease and 5) post-harvest physiological deterioration.

The International Programs Office manages intellectual property issues associated with the grant, pursues access to third party intellectual property and provides assistance to researchers on regulatory procedures for field testing of improved cassava developed. The Office works with the laboratories of Dr. Claude Fauquet, Dr. Daniel Schachtman, and Dr. Edgar Cahoon to implement this project.

For more information about the project, please see the BioCassava Plus website at http://biocassavaplus.org.

Disease-Resistant Cassava for Kenya

The goal of the Disease-Resistant Cassava for Kenya project, with funding from USAID, is to develop and deliver transgenic, disease-resistant cassava planting materials to farmers in Kenya to increase their harvests and improve their food security.

The International Programs Office is working in close partnership with the Kenya Agricultural Research Institute to test transgenic cassava plants modified for resistance to Cassava mosaic disease (CMD) under natural field conditions.

Virus-resistance technology will initially be deployed in the East Africa region’s most popular cultivar – Ebwanatareka – for adoption by the 32,000 Kenyan farming families that already know and like this type of cassava. Successful achievement of the project goal will help 200,000 Kenyan cassava farmers and their family members increase their food security by controlling CMD and increasing their cassava harvests by 50% on a sustainable basis. A fifty percent increase in yield for these families will generate an additional 63,000 metric tons of food each year. For a poor Kenyan family, an extra 2,000 kilograms of food each year represents a significant increase in food security, whether that family consumes the cassava directly or sells it to finance purchases of other essentials such as medicines, tools, or other foods.

Because Ebwanatareka is also popular and widely grown in neighboring Uganda, the success of this project will result in benefits that go beyond increased food security in Kenya. By deploying the same transgenic cultivar in Uganda, annual production of cassava in that country will increase by over 600,000 tons, and the total number of beneficiaries in both countries will increase to over one million persons.

The success of this project will serve to inspire and facilitate subsequent investments in transgenic technologies to generate CMD-resistance in additional popular cassava cultivars, thereby spreading the technology’s benefits to millions of additional farmers throughout Africa.

Southern Africa Biotechnology Program (SABP)

The primary goal of the Southern Africa Biotechnology Program, funded by USAID, is to facilitate the application of biotechnologies in the Southern Africa region in order to increase agricultural productivity and expand trade opportunities. As a consequence there will be increased rural incomes and food security.

Cassava mosaic disease (CMD) is the major constraint for cassava production in Southern Africa. This applies to cassava grown for food as well as for starch production, both at the smallholder and commercial level.

The purpose of the present funding will be to evaluate the existing GM lines developed at the Danforth Center for CMD-resistance against the virus species responsible for CMD in Southern Africa. After testing these GM cassava plants against the South African cassava mosaic virus (SACMV), and if the greenhouse results are satisfactory, this project will start field testing the best performing lines of these transgenic cassava in South Africa, depending on the approval of biosafety permits by the regulatory authorities in that country. The International Programs department will assist with these efforts.

In Southern Africa, cassava has much potential as a source of industrial starch. Starch production is one of the most important agro-industries worldwide, with a total value of around US$20 billion.  The industrial modification of native starches has expanded the range of potential uses of cassava. The genetic modification of starches could tailor particular products to specific industrial needs and reduce processing costs. Opportunities in both food production and starch production can boost the food security and raise the incomes of small farmers.

Virus-Resistance Cassava for Africa (VIRCA)

The Danforth Center recently received a 5-year grant from a private foundation to pursue the development and delivery of virus resistant cassava varieties to African smallholder farmers.  The Virus-Resistant Cassava for Africa (VIRCA) project will result in significant increases in cassava root yields, thereby enhancing the food security of the cassava producing regions of Africa.

The primary goal of the project is to deliver farmer-preferred transgenic cassava varieties to African farmers.  Danforth Center staff will work with local partners to identify target varieties, generate transgenic events, conduct field trials in the target countries and secure regulatory approval for commercialization. A secondary goal is to build ownership and capacity in the target countries. Scientists from each target country will participate in each step of the project at initially at the Danforth Center, and then will proceed to develop cassava transformation programs in their home countries.

In order to maximize the potential impact, the VIRCA project will focus on three target countries.  The selection of target countries will be based on: (1) the importance of cassava as a staple crop; (2) the level of CMD pressure; (3) the availability and interest of local partner institutions; and (4) the presence of a functioning biotechnology regulatory system.