Striga hermonthica (“witchweed”) is one of Africa’s most destructive parasitic weeds, severely constraining cereal production—especially maize and sorghum. It infests tens of millions of hectares, often causing 20–80% yield losses and, in heavily infested fields, complete crop failure. This disproportionately affects smallholder farmers and perpetuates food insecurity and poverty. Current control strategies are costly, inconsistently effective, or poorly accessible, and they rarely prevent Striga seed germination triggered by host-derived signals.
Sophoridine—an alkaloid predominantly isolated from Sophora spp. (Fabaceae)—binds Striga receptors (e.g., ShHTLs), thereby inhibiting seed germination. However, its availability is limited because Sophora is not native or widely cultivated in Africa. There is an untapped opportunity to identify local Fabaceae crops and wild species that naturally produce sophoridine or related alkaloids, which could provide accessible, plant-based Striga suppression—especially when intercropped with maize.
Key Gaps
- Unknown African Sources of Sophoridine: Little is known about which indigenous or cultivated Fabaceae species in Africa synthesize sophoridine or analogous compounds.
- Lack of Bioactivity Screening Pipelines: There is no systematic screening of Fabaceae germplasm linking chemical profiles to Striga germination inhibition.
- Limited Translation to Cropping Systems: Even where promising compounds exist, few studies integrate them into farmer-relevant systems such as maize–legume intercropping.
CWISA’s Scientific Approach
CWISA will develop a science-based discovery-to-deployment pipeline that:
- Screens cultivated and wild Fabaceae species in Kenya and the wider region for sophoridine and related alkaloids.
- Quantifies alkaloid content and tests bioactivity on Striga germination and receptor binding (ShHTLs) under laboratory and greenhouse conditions.
- Identifies elite Fabaceae candidates suitable for intercropping with maize to provide in-field biochemical suppression of Striga.
- Co-develops agronomic guidelines with farmers to ensure scalable, climate-smart adoption.
By valorising accessible Fabaceae plants as living biopesticide allies, CWISA aims to reduce Striga pressure, improve maize productivity, and strengthen smallholder livelihoods.
Proposed Objectives
- Identify and quantify sophoridine (and analogues) across a diversity of cultivated and wild Fabaceae species in Kenya and surrounding regions.
- Evaluate the inhibitory effects of Fabaceae-derived extracts on Striga hermonthica germination and ShHTL receptor activity.
- Field-validate promising Fabaceae species in maize intercropping systems to assess Striga suppression, crop performance, and farmer uptake potential.
Contact: info@cwisa.org