Abstract
The structure of seed system networks provides important information about epidemic risk within the network. We evaluated the structure of a sweetpotato seed system in Northern Uganda in terms of its utility for distributing improved varieties and its vulnerability to the spread of potential seed-borne pathogens. Sweetpotato sellers were surveyed in the Gulu Region of Northern Uganda. Weekly vine sales transactions were tracked through the growing season (April-October) creating a robust dataset of planting material sales over time, including price, village sold to, volume, and information about the buyer and seller. From this dataset of known transactions and the distance between villages, a network of vine movement was constructed. In silico simulations of the introduction of a novel virus into the systems indicated the potential for rapid spread. Through simulation of multiple epidemic starting points, nodes of particular importance to disease sampling and mitigation were identified. This method can serve as an example, with potential to be used across a wide variety of seed systems.
Footnotes
Mailing address: Plant Pathology Department, University of Florida, Gainesville, FL 32611-0680, United States