International Collaboration Receives Regulatory Approval of Disease Resistant Cassava in Kenya

ST. LOUIS, MO, August 3, 2021The Kenya Agricultural and Livestock Research Organization (KALRO) has received approval from the Kenyan National Biosafety Authority (NBA) for environmental release of cassava that is resistant to cassava brown streak disease (CBSD). The approval paves the way for conducting national performance trials (NPTs), the final step of testing new varieties before they can be registered and released to farmers. 

The disease-resistant cassava was developed under the Virus Resistant Cassava for Africa Plus (VIRCA Plus) project, an international collaboration between the Donald Danforth Plant Science Center in St. Louis, MO, the Kenya Agricultural and Livestock Research Organization (KALRO), the National Agricultural Research Organisation (NARO) in Uganda, National Root Crops Research Institute (NRCRI) in Nigeria and the Rwandan Agriculture Board (RAB), with ISAAA AfriCenter and SCIFODE providing communication and policy outreach support.

National Performance Trials are a routine requirement for all new crop varieties and an essential step in demonstrating value for cultivation and use prior to registration and release to farmers. NPTs will be conducted to the requirements of the Kenya Plant Health Inspectorate Service (KEPHIS) and the National Environment Management Authority (NEMA), will look at performance against diseases, pest resistance and yield, and are expected to take two cropping cycles across the different cassava agro ecologies of Kenya. During this next phase, VIRCA Plus, along with new partner Mennonite Economic Development Associates (MEDA), is also developing a system to multiply, deliver and steward the new disease-resistant cassava varieties to Kenyan farmers once they are registered and fully approved by regulatory authorities. 

“The National Biosafety Authority approval for Environmental release of Cassava Event 4046 is an important stride forward for cassava improvement in Kenya,” said Catherine Taracha, coordinator Crop Biotechnology at Kenya Agricultural Research Institute. “The approval brings the many efforts of international and regional organizations one step closer to the goal of delivering cassava with enhanced resistance to CBSD to farmers, contributing to Kenya's food security and economic growth."

Through a decision document dated June 18, 2021, the NBA Board approved the application following necessary review in accordance with the country’s Biosafety Act. To develop the resistant variety, researchers used modern biotechnology to introduce a small part of two viruses that cause CBSD into the cassava plant and trigger naturally occurring defenses already present in the plant. This enables the plant to activate its defense mechanisms prior to arrival of the pathogen and resist development of the disease.

The improved cassava was evaluated over a period of five years in more than 20 confined field trials (CFTs) across six different locations in Kenya and Uganda. It has continued to show high and stable defense against CBSD, a disease that can result in up to 100 percent loss of usable storage roots in severe infection. It is now under testing in Rwanda. 

According to NBA’s Chief Executive Officer, Prof. Dorington Ogoyi, the decision was arrived at following a rigorous and thorough review, taking into account food, feed, and environmental safety assessment as well as consideration of socio-economic issues. The review process included a public comment period for 30 days, in line with the Kenyan constitution that calls for public participation. 

“This is a welcome decision and a significant step to getting disease-resistant cassava into the hands of Kenyan farmers for addressing food security challenges,” said KALRO Director General Dr. Eliud Kireger. “We thank the NBA and all those who participated in the review for their diligent consideration of the application.”

Cassava is an important staple food crop for one-third of Africa’s population who rely on its starchy tuberous roots for over 50% of their daily caloric intake. It is an excellent source of carbohydrates and calories and a hardy crop, that grows relatively well in conditions of heat, drought and low soil fertility prevalent in many African countries. Cassava is an important subsistence crop for smallholder farmers across much of sub-Saharan Africa. It is also increasing in importance as a cash crop for manufacturing biofuel, beverages and processed products, providing income for smallholder farmers and fueling economic development. However, cassava production is threatened by CBSD, which rots the starchy storage roots and can destroy yields from entire fields.

“Often you can’t see CBSD — the symptoms on the leaves can be very mild,” said Nigel Taylor, PhD,  Dorothy J. King distinguished investigator at the Danforth Center who has been working on the project for nearly 20 years. “But when you dig up the storage roots there are big, brown lesions. It makes the roots inedible. You can’t feed them to animals. You can’t sell them — they’re ruined. Today, we are one step closer to providing farmers with a solution to cassava brown streak disease and bringing about better livelihoods for farming households in Kenya.” 

Funding for the project was provided by The Bill & Melinda Gates Foundation, the United States Agency for International Development as part of Feed the Future, the U.S. Government’s global food security initiative, Bayer Crop Science with in-kind contributions from partner country governments. 

About VIRCA Plus
VIRCA Plus is a multi-institutional project working to improve resistance to viruses that cause cassava brown streak disease and to increase levels of iron and zinc in the storage roots, the edible part of the plant. VIRCA Plus collaborates with research scientists, regulatory experts and communication specialists and with the National Agricultural Research Systems (NARS) in Kenya, Uganda, Nigeria and Rwanda. For more information please visit,


For additional information contact:
Karla Roeber, Vice President, Public and Government Affairs, (314) 406-4287