Cassava roots do not contain the key nutrients iron and zinc at levels that are adequate to meet minimum daily requirements, especially for women and children. Cassava varieties that have higher levels of iron and zinc could make a significant contribution to nutrition and health of families in Africa.
The need: more nutritious cassava
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 across sub-Saharan Africa an estimated 24% of the population are at risk from zinc deficiency due to inadequate dietary intake.
Cassava roots are an excellent, low cost source of starch year-round, but they contain a fraction of the iron and zinc required in a healthy diet. The primary source of dietary iron and zinc for rural and urban resource poor is obtained through consumption of plant foods, especially legumes, leafy vegetables and whole grain cereals. However, access to the required quantity of these foods is often seasonal and the quality is not assured.
Our work: developing cassava varieties with higher levels of both iron and zinc
Researchers have not been able to raise the iron and zinc content of cassava storage roots through conventional plant breeding of existing cassava varieties and breeding lines. Genetic engineering is being used to incorporate two genes from another plant, Arabadopsis, that function to elevate iron and zinc content in cassava roots. We have succeeded in developing and testing cassava plants that accumulated greater than 10 times more iron and zinc than comparable varieties.
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. The storage roots of this nutritionally enhanced cassava retain higher levels of iron and zinc even after peeling, boiling and other processing methods used to produce common West African foodstuffs, such as gari and fufu.
Breeding will also be used to incorporate this trait into high-performing cassava varieties that meet the needs of farmers and consumers. 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.