SciDev.Net

An improved variety of cassava

CGIAR

Millions of Africans rely on cassava, also known as manioc, to provide them with food through drought and war. This nutritious root tuber grows with minimal tending and in poor soil, even when other plants succumb to drought.

But in the past five years a virus ― the brown streak virus ― has spread throughout cassava crops in sub-Saharan Africa.

The virus destroys the root while the leaves stay healthy-looking so farmers don't realise that their entire crop has been ruined until harvest time.

The virus wipes out whole fields of plants; in Tanzania, cassava yields have fallen 50 to 80 per cent in the past five years, according to this New Scientist article.

Scientists from the International Institute for Tropical Agriculture (IITA) in Tanzania suspect the virus is spread by people ― migrants, refugees or traders ― carrying infected cassava cuttings across Africa.

To tackle the problem, IITA researchers are developing new varieties of cassava through cross-breeding, and trials have shown that these successfully tolerate the virus.

To speed up the spread of these new varieties, the IITA is now training farmers in a new method to increase the number of cuttings obtained from each plant.