Why It Matters?

Sclerotinia Head Rot is a major disease affecting sunflower production in South Africa, causing severe yield losses and threatening crop viability in certain seasons. With no resistant cultivars available and current management strategies offering limited control, innovative approaches are needed. This project explores the use of plant growth regulators (PGRs) to shift sunflower flowering periods, helping plants avoid head rot infection. If successful, this approach could become a cost-effective, practical tool for farmers to reduce losses and improve disease resilience without disrupting planting schedules.

Research Approach

The study is evaluating eight plant growth regulators both in laboratory and plant-based conditions. Trials are assessing the regulators’ ability to inhibit the fungus Sclerotinia sclerotiorum, alter sunflower flowering (anthesis), and reduce head rot infection severity. Experiments include fungal growth tests, detached head inoculations, and full-field flowering assessments. Promising compounds, such as paclobutrazol, salicylic acid, and naphthaleneacetic acid, are being further tested. The project also includes new tools such as a stigma receptivity assay and digital phenotyping, with collaborations extending to international partners.

Research Impact to Farmers

By identifying plant growth regulators that help sunflowers flower outside high-risk Sclerotinia head rot windows, this research could empower farmers with an environmentally friendly, flexible disease management tool. This “flowering escape” strategy reduces dependence on fungicides and avoids the logistical complications of staggered planting. For rain-fed systems where planting dates are unpredictable, this innovation could significantly reduce losses, improve yield stability, and increase profitability. Ultimately, the project supports more sustainable sunflower production and strengthens resilience against climate-sensitive diseases like Sclerotinia.

Resources

Reports

Interim findings reported to funders and collaborators (available upon request)

Articles

Collaborators & Research Leads

• Principal Investigator
• Dr. Nicky Creux – University of Pretoria
• Collaborating Institutions
• University of Pretoria
• ARC – Biotechnology Platform (ARC-BTP)
• Soltis (France)
• INRAE (France)

Students and Technicians

• Ms Nomfundo Shinga – PhD Student (2023 cohort)
• Ms Jolize Kruger – BSc (Hons) Student (2024)
• Ms Jessica Berry – MSc Student (stigma receptivity assay)
• Ms Tshego Mbere – MSc Student (digital phenotyping app)