Impact of Rhizomania Virus (Beet necrotic yellow vein virus) on Sugar Beet Yield and Qualitative Characters

Rhizomania disease is one of the world's most important sugar beet diseases. The disease causal agent is Beet necrotic yellow vein virus. This disease is widespread. In this study, impact of rhizomania on sugar beet yield and qualitative characters consisting of root yield, sugar content, sugar yield, sugar extraction coefficient and amount of non-sugar impurities of root (sodium, potassium, and amino nitrogen) were investigated. For this purpose, 12 monogerm sugar beet cultivars including six commercial cultivars resistant to rhizomania, three tolerant cultivars, and three susceptible cultivars to the disease were planted in a randomized complete block design with three replicate in rhizomania non-infested and infested fields. This study was carried out in two years at Fars Agricultural and Natural Resource Research and Education Center (Zarqan). Results showed that rhizomania reduced the sugar yield by imposing a negative effect on root yield and sugar content. The average decrease in sugar yield in infected treatments, for commercial resistant, tolerant, and susceptible cultivars was 25, 54, and 90%, respectively. Under rhizomania infection conditions, sodium content of all cultivars increased, on average by 165%, but their amino nitrogen content showed an average with 43% reduction. The presence of rhizomania symptoms in resistant cultivars and yield reduction under infection conditions showed that Rz1 gene can not cause the full resistance to the disease.