The parasitic witchweeds, such as Striga hermonthica and Striga asiatica, pose an enormous threat for production of cereal crops, such as sorghum, millet and maize, in the African continent, threatening the livelihood of millions of people, especially in sub-Saharan Africa. Striga seeds lay dormant in the soil until their germination is triggered by strigolactones (SLs), signaling compounds exuded by roots of plants, including maize. Maize exudes at least six different SLs from its roots into the rhizosphere, two of which were structurally identified as zealactone and zeapyranolactone. In work on maize strigolactone biosynthesis that was part of the ERC Advanced grant CHEMCOMRHIZO we demonstrated that there is natural variation in the germination stimulant composition in the root exudate of maize varieties and that this results in a degree of Striga resistance. We have elucidated the entire biosynthetic pathway of all SLs in maize and we showed that the difference in strigolactone composition is the result of a difference in the expression of one of the genes in the pathway. The line with the strongest reduction in the expression of this gene, a North-American cultivar, displays almost full Striga resistance compared with a susceptible control. In collaboration with the CGIAR institute CIMMYT, we propose to create knock-out lines in this gene in two elite African maize varieties to deliver the proof-of-concept that this Striga resistance can be introduced into Africa.

Food and nutrition security (FNS) remains a challenge for Africa, despite efforts made in agricultural research and extension in the past, due to inefficient implementation and exchange of technologies and knowledge to end users. The main objective of InnovAfrica is to improve FNS by integrating sustainable agriculture intensification (SAI) systems, innovative institutional approaches (IIAs) with novel extension and advisory services (EASs) and enhancing smallholder adaptive capacity in Sub-Saharan Africa (SSA). InnovAfrica addresses main challenges of the work programme (SFS-42-2016), through a strong multidisciplinary EU-Africa consortium of 16 partners, supported by 6 active Multi-Actor Platforms (MAPs) in 6 case countries (Ethiopia, Kenya, Malawi, Rwanda, Tanzania and South Africa). InnovAfrica will test, integrate, and disseminate SAI systems suitable to smallholders, institutional approaches (e.g. MAPs, seed delivery systems) and EASs (e.g. dynamic knowledge platforms supported by smart phones, Village Knowledge centers). The main outcomes of InnovAfrica include: i) better understanding of the needs and opportunities of SAI systems in Africa, ii) improved knowledge and innovation capacity of farmers to implement SAI systems supported by IIAs and EASs, iii) improved product value chains through viable IIAs benefiting women and youth, iv) Innovative policies, increased knowledge of public-private partnerships to strengthen agri-business model in case countries with a view to upscaling successes in other regions through functional MAPs, v) Wider dissemination of SAI systems to smallholders and women within and outside project areas through effective use of smart phones and social media, and vi) Stronger EU-Africa Research and Innovation Partnership to achieve FNS. The outcomes will contribute to smallholder productivity, profitability; and nutritional benefits while reducing negative environmental impacts and enhance FNS and sustainable agriculture in Africa.