Effect of maize lethal necrosis disease on seed quality of commercial hybrid varieties

The recent maize outbreak of maize lethal necrosis (MLN) disease is a big threat to the already strained food security in Kenya. The disease is caused by co-infection of maize with Maize chlorotic mottle virus and cereal potyviruses mostly Sugarcane mosaic virus. The disease has spread to many parts in Kenya causing losses of up to 100%. The objective of the study was to assess the transmission of viruses causing maize lethal necrosis disease through seeds. Seeds of 12 maize varieties were harvested from plants infected with at least 60% MLN disease severity and the seeds were evaluated for quality parameters including mould contamination, shriveling, germination, seedling length, seedling dry weight and vigour. Infection of maize with maize lethal necrosis (MLN) disease significantly increased the proportion of shriveled, discoloured and mouldy seeds. Seedlings from MLN disease-infected plants showed significant reduction in length, dry weight and vigour as compared to seedlings from certified seeds. The study showed that viruses causing maize lethal necrosis disease are transmitted through seed resulting in plants with low emergence, vigour and yield.