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

The Needs: More Nutritious Food, Better Yields & Incomes

In sub-Sarahan Africa, cassava is the second most important staple food crop after maize and an important cash crop for small-holder farmers. Approximately one-third of the population relies on cassava’s starchy tuberous roots for over 50% of their daily caloric intake. It grows well in conditions of drought and low soil fertility 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. Cassava Brown Streak Disease (CBSD) destroys the edible roots even when rest of the plant looks healthy, and Cassava Mosaic Disease (CMD) can stunt or kill plants outright.

Although it is an excellent source of calories, cassava does not contain sufficient levels of key nutrients such as iron and zinc to meet minimum daily requirements, especially for women and children. Iron deficiency anemia compromises the immune system, stunts growth and impairs cognitive development in children while deficiency in zinc causes increased risk of death from diarrhea, stunting and reduced cognitive development. In Nigeria alone, 75% of preschool children and 67% of pregnant women are anemic, and in sub-Saharan Africa an estimated 24% of the population are at risk of zinc deficiency due to inadequate dietary intake.

The VIRCA Plus Project

The VIRCA Plus collaboration is addressing these challenges by improving cassava in two important ways.

Disease Resistance
VIRCA Plus is developing cassava varieties that will be resistant to both Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD). Both diseases are spread by white-flies and by diseased cuttings that are unknowingly shared among farmers.

African and international organizations worked together during earlier phases of the VIRCA project (2005-2016) 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.

The VIRCA Plus project now employs conventional plant breeding techniques to combine transgenic CBSD resistance with farmer-preferred cassava varieties that are already resistant to CMD. Field development and testing of these new varieties is ongoing in Kenya and Uganda to ensure that they control both plant diseases while producing good yields and maintain farmer preferences for taste, texture, processing and storage practices.

Nutritional Enhancement

VIRCA Plus is also developing cassava varieties that have elevated levels of both iron and zinc for improved nutrition, as well as resistance to cassava disease.

The BioCassava Plus project (2005-2016) 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 have shown that cassava roots could possibly provide 40-70% of the Estimated Average Requirement of these minerals for vulnerable women and children after processing into common African foodstuffs, such as gari and fufu.

Cassava varieties that are preferred by farmers and consumers in Nigeria and other West African countries will be the first targets for nutritional enhancement under VIRCA Plus.

Looking Ahead

Over the coming years, scientists will be developing, observing and assessing VIRCA Plus improved cassava varieties in government-regulated field trials and other evaluations required for products of modern biotechnology.

VIRCA Plus varieties will be released to breeders, farmers and ultimately to consumers in partner countries only after they have been thoroughly reviewed by government bio-safety agencies according to national frameworks and laws.

VIRCA Plus cassava varieties are expected to be 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, Missouri, USA
Kenyan Agricultural and Livestock Research Organization (KALRO)
ISAAA AfriCenter in Kenya
The International Institute for Tropical Agriculture (IITA), at BecA-ILRI
National Root Crops Research Institute (NRCRI)
The Open Forum for Agricultural Biotechnology (OFAB) Nigeria Chapter
National Biotechnology Development Agency (NABDA)
National Crop Resources Research Institute (NaCRRI)
National Agricultural Research Organization (NARO)
Science Foundation for Livelihoods and Development (SCIFODE)

November 2017

  • VIRCA Plus Fact Sheet


    More Info
  • Contact:

    Nigel Taylor, Ph.D.
    Member and Dorothy J. King Distinguished Investigator
    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