Prospects of Mitigating Late Blight Disease of Potato in Nigeria through Deployment of Triple R (3R) Stacked Gene Transgenic Varieties

Abstract

Potato (Solanum tuberosum) is a cherished staple food in Nigeria. Low average yield of about 4.3t/ha obtained locally is partly due to 20-50% yield reduction caused by late blight disease (LBD) (caused by species of oomycetes known as Phytophthora infestans). Based on a price of $150 per ton for potato, the cost of late blight disease is estimated at between $42,000,000 – $105,000,000 per annum. Development and deployment of resistant varieties remain the most economic and environmentally sustainable way to control plant diseases. Stacking resistance R genes for Phytophthora into farmer-preferred varieties from wild relatives by conventional breeding takes decades to realize, especially when working with polyploids and crops suffering from inbreeding depression. Genetic transformation techniques provide a more direct transfer mechanism into existing elite varieties lacking resistance to LBD. The 3R biotech potato was developed by the International Potato Center (CIP) by transferring three R genes selected from unmodified DNA fragments of Solanum bulbocastanum, and Solanum venturii into farmers’ preferred varieties lacking resistance to LBD. These genes were chosen for their ability to recognise a broad spectrum of strains of P. infestans. The efficacy and safe use of 3R Potato have been demonstrated in Uganda and can be scaled out in Nigeria to mitigate the threat posed by LBD. Regulatory approvals for confined field trials of lead events, environmental and commercial release, robust extension and adoption of prospective 3R biotech potato varieties by relevant stakeholders will contribute significantly to food security in Nigeria. The prospects are brightened by extant policy environment which appears conducive for obtaining the required regulatory approvals for trial and deployment of potato varieties stacked with 3 R resistant genes.