Assessment of prevalence and distribution of potato viruses in Ethiopian seed systems

Abstract Viruses are among the significant biotic constraints burdening global potato production, particularly in developing countries where seed certification is not common and production, availability and accessibility to quality seed potato is a big hindrance. Virus infection in seed potato reduces yield, and the problem is exacerbated when an early-generation seed is affected. The prevalence of six key potato viruses, PVY, PVX, PLRV, PVA, PVS, and PVM, was assessed among decentralized seed multipliers such as individuals, farmer seed group cooperatives, private companies, and agricultural research center that produce early generation seed in six major potato growing districts in Ethiopia. A total of 262 leaf samples were randomly collected from potato plants and analyzed using a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for potato viruses. Potato virus prevalence was calculated as the proportion of samples that tested positive for the viruses against the total number of samples tested. Only 1.8% of the samples were virus-free, while 98.2% of the samples collected from farmers' fields were infected with at least one of the six viruses. About 17% of the samples had a single viral infection with one of the six viruses, whereas 81% had multiple infections. Early generation seed and germplasm samples collected from breeding, research, and private screenhouses were infected with PLRV (68.1%), PVY (57.4%), PVS (40.4%), PVM (34%) and PVX (23.4%). These results indicate that virus infection is widespread in the country, posing challenges and threats potato production and food security efforts. To address this issue, it is critical to developing a robust system that prevents viral infection build-up and spread in the seed system through regular seed quality assurance and certification, particularly for early generation seed. Furthermore, smallholder farmers need to use an integrated management approach to effectively combat potato viruses.