Susceptibility of Cassava Varieties to Disease Caused by Sri Lankan Cassava Mosaic Virus and Impacts on Yield by Use of Asymptomatic and Virus-Free Planting Material

Cassava (Manihot esculenta Crantz) is a rainfed, smallholder-produced crop in mainland Southeast Asia, and currently facing serious challenge posed by the introduction of cassava mosaic disease (CMD). This study assessed susceptibility popular Asian varieties to CMD, yield penalties associated with disease, efficacy selecting clean or asymptomatic plants as seed for following season. Field experiments evaluated agronomic management practices (i.e., fertilizer application, use symptomatic stakes) Cambodia six nine over three seasons under natural pressure. Popular KU50 Huaybong60 showed superior CMD tolerance, consistently fewer plants, lower progress measures, higher yields. Plants demonstrating symptoms at early stages development, i.e., 60 days after planting, yielded significantly less than those developing later 270 DAP) not all. grown from stems on average 20% 2.7-fold planting material. A decline ~50% was recorded materials susceptible (e.g., SC8, ~25 t ha−1) successive years. The findings emphasize that farmers could positive selection choosing reduce losses.