Evaluation of sugar beet lines for resistance to beet curly top viruses

Curly top disease caused by beet curly top viruses (BCTVs) has been a problem in sugar beet fields for a long time. In recent years, climate change has increased the spread of virus vectors and disease damage in infected regions. To find a natural resistance source to curly top viruses in Iran (Beet curly top virus-C, BCTV-C and Beet curly top Iran virus, BCTIV), the reaction of 50 sugar beet lines to the above-mentioned viruses was evaluated in a completely randomized design experiment in 2014. Sugar beet lines were agroinoculated at the 4–6 leaf stage by virus infectious clones under greenhouse condition and then the symptom severity and virus presence was monitored by enzyme-linked immunosorbent assay and polymerase chain reaction methods 8 weeks after inoculation. Five out of 50 lines were found to be resistant to both viruses. Given that both viruses were detected in most sugar beet cultivation areas in Iran, these lines could be suggested for cultivation in Iran. In addition, some lines displayed completely different reactions to the viruses indicating different effects of the viruses on sugar beet lines.