Virus Yellows in sugar beet – possibilities to achieve virus resistance

Virus yellows in sugar beet is caused by different virus species. Monitoring has shown that Beet yellows virus (BYV), Beet mild yellowing virus (BMYV), Beet chlorosis virus (BChV) are common and widespread, while Beet mosaic virus (BtMV) is less prevalent. The green peach aphid (Myzus persicae) is considered the main vector of these viruses. Sugar beet varieties with resistance or tolerance traits are currently not available to practical growers, therefore it is imperative to support breeding efforts with improved strategies to achieve virus resistance. For this purpose, a field test was established in which yield differences between susceptible and tolerant varieties can be generated by a 3% inoculation with BMYV-carrying aphids. A greenhouse bioassay has also been developed to distinguish susceptible and tolerant genotypes following BYV infection. Both assays pave the way for future use of natural resources such as wild forms and other breeding material to screen for virus resistance. In addition, molecular biology approaches are used to identify plant susceptibility factors of the plant-virus interaction, which will be knocked out via modern precision breeding methods to generate recessive virus resistance. Consequently, genotypes with naturally occurring mutations in the appropriate factors can be used for crossbreeding processes into elite breeding material.