African Centre for Crop Improvement

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African Centre for Crop Improvement

“Training African Breeders on African Crops, in Africa”


Funding will bring Striga-Resistant Sorghum to Farmers

The battle against Striga in Tanzania and South Africa took a step forward with the arrival of funding to register and commercialise new varieties of Striga-resistant sorghum, developed by our recent graduate, Dr Emmanuel Mrema.
The funding will also cover the registration and commercialisation of a biocontrol agent, Fusarium oxysporum f.sp. strigae (FOS), that the sorghum varieties have been bred to be compatible with. The funding comes from Technology and Innovation Agency (TIA), a unit of South Africa’s national Department of Science and Technology, working with the Tanzanian Government.
Striga is a parasitic weed that wreaks havoc on sorghum, maize, millet, rice and wheat, and is a huge problem in Tanzania, with two species affecting small-scale farms especially badly. Mrema, who is from Tanzania, successfully focused his PhD research on breeding new sorghum varieties for resistance to both of the Striga species, and for compatibility with FOS.
“Emmanuel has shown that this combination of breeding and biocontrol has worked brilliantly against both Striga species, but it is not going to get to the farmers, unless his varieties and the biocontrol agent are both registered,” says ACCI Director Professor Mark Laing.
Prof Shimelis (left) and ACCI graduate Dr Solomon Assefa stand in a field of sorghum that has been invaded by colourful Striga
“The main aim of this project is getting this affordable technology to farmers, so our goal is to register the resistant varieties that are compatible with FOS, and to get FOS registered as a biocontrol agent, in both SA and Tanzania.”
Laing says to achieve this, Mrema and the ACCI have to do formal registration trials — i.e. grow them for two seasons and show that they are stable and a single variety, and that their yields are stable and consistent.
“Then with the biocontrol agent, you have to do efficacy trials and also have to do at least two seasons in at least two provinces,” says Laing. “You also have to show that it won’t be damaging any other organisms, other than the target weeds.”
“We will have to depend on an industry partner to do that in both countries. Ultimately, registration of the sorghum varieties has to come from a commercial seed company, so we’re working with the plant breeders at SeedCo where the research team is headed by former ACCI graduate, Dr John Derera.


Another ACCI PhD student, John Lobulu, is currently doing a project on breeding and biocontrol of Striga in maize in a slightly wetter area in Tanzania. SeedCo will commercialise both the maize and sorghum varieties, while the ACCI is working with a South African biocontrol company, Plant Health Products (PHP), to register and commercialise the FOS.
Admire Shayanowako, another PhD student, is currently doing his research on developing Striga-resistant maize in South Africa, and his varieties will also need to be registered and the FOS label expanded to include maize as target crop.
Shelagh McLoughlin
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