VIRCA Plus: Virus-resistant and Nutritionally-enhanced Cassava for Africa

Scientists under VIRCA Plus are developing improved cassava varieties to enhance the livelihoods and health status of African farm families.

The Needs: More Nutritious Food, Better Yields & Incomes

Cassava is an important food and cash crop for small-holder farmers in Africa. It is the second most important staple food crop after maize in sub-Saharan Africa. Approximately one-third of the population relies on its starchy tuberous roots for over 50% of their daily caloric intake. It grows well in conditions of drought and low soil fertility, which are prevalent in many African countries. However, plant viral diseases can destroy up to 100 percent of a cassava crop yield, threatening livelihoods and leading to hunger. Although it is an excellent source of calories, cassava does not contain significant levels of key nutrients such as iron and zinc to meet minimum daily requirements, especially for women and children. In Nigeria alone, 75% of preschool children and 67% of pregnant women are anemic.

The VIRCA Plus Project

The VIRCA Plus collaboration is building on the successes of earlier work to address these challenges by developing and delivering two products.

Disease Resistance

The first product will be East African cassava varieties with resistance to both Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease.

During the earlier phases of the VIRCA project in 2011-2015, African and international organizations worked together to develop cassava with strong and stable resistance to CBSD, using genetic modification techniques. The VIRCA team conducted several confined field trials in both Uganda and Kenya, with the approval, oversight and guidance of government regulators.

With expertise of local and international scientists, the VIRCA Plus project is now employing conventional plant breeding techniques to bring transgenic CBSD resistance into cassava varieties that are resistant to CMD. By doing this, the two viral diseases will be brought under control among farmer preferred varieties. VIRCA Plus research in this effort is currently on-going at the field testing stage in Kenya and Uganda.

Nutritional Enhancement

The second product will be a Nigerian cassava variety with elevated levels of iron and zinc for improved nutrition, as well as disease resistance.

The BioCassava Plus project that ran from 2006 to 2015 succeeded in developing and testing cassava plants that accumulated greater than 10 times more iron and zinc than comparable varieties, using the tools of modern biotechnology. Field trials of this cassava in Puerto Rico produced roots in which both minerals are retained after processing into common foodstuffs at levels that could provide 40-70% of the Estimated Average Requirement for vulnerable women and children.

VIRCA Plus focuses on further development of high iron and zinc cassava varieties that are preferred by farmers and consumers in Nigeria and other West African countries. This is being done in collaboration with the National Root Crops Research Institute (NRCRI), Nigeria.

Looking Ahead

Over the coming years, our scientists are developing, observing and assessing VIRCA Plus improved cassava varieties for effectiveness of the improvements, root yield, harvest and safety. Approved field trials will be part of these evaluations. The team cooperates with national government regulators and will provide all necessary safety data and required information about VIRCA Plus varieties before they are approved for cultivation by farmers.

VIRCA Plus varieties are expected to be accessible and available to farmers in a similar manner and cost to cassava currently available from national research organizations.

Participating Organizations

The Donald Danforth Plant Science Center in St. Louis, MO, USA; the National Root Crops Research Institute (NRCRI) and the OFAB Nigeria Chapter,  National Biotechnology Development Agency (NABDA)  in Nigeria; the National Crop Resources Research Institute (NaCRRI) / National Agricultural Research Organization (NARO) and the Science Foundation for Livelihoods and Development (SCIFODE) in Uganda; the Kenyan Agricultural and Livestock Research Organization (KALRO) and the ISAAA AfriCenter in Kenya; and the International Institute for Tropical Agriculture (IITA).


December 2016

  • VIRCA Plus Fact Sheet


    More Info
  • Contact:

    Nigel Taylor, Ph.D.
    Interim Director
    975 N. Warson Road
    St. Louis, MO 63132, U.S.A.
    Tel: 314-587-1257
    Fax: 314-587-1357
    Email: ntaylor@danforthcenter.org 


    Ann Kruse
    (314) 587-1443