Breeding for resistance to rhizomania in sugar beet: A review

Currently rhizomania is the most important disease insugar beet worldwide, and attack can lead to seriousyield losses. The disease is caused by beet necroticyellow vein virus (BNYVV) that is transmitted by thesoil-borne fungus Polymyxa betae. Breeding sugarbeet cultivars with resistance to rhizomania isregarded as the most appropriate way to enablecontinued production of this crop in BNYVV-infestedfields and also to slow the spread of the disease.Breeding for resistance started with selection byscoring disease symptoms in field experiments. Thedevelopment of non-destructive greenhouse tests, withdetermination of the virus concentration in rootletsusing ELISA, has greatly improved the efficiency ofselection. In this paper the impact of scientificresearch on the progress in breeding cultivars withresistance to rhizomania is reviewed. This includesthe distribution, composition, and pathogenicity ofthe virus, the sources of resistance to virus andvector, the genetics of virus resistance, progresswith breeding methods, and the use of molecularmarkers and pathogen-derived resistance. The yieldsand quality characteristics of recently introducedresistant cultivars now equal those of the commercialsusceptible cultivars.