The origin of rhizomania resistance in sugar beet

In the last 35 years, breeding has greatly reduced the damages caused by rhizomania in sugar beet crops. After the first encouraging results using the Alba genotypes, the cultivar Rizor represented a substantial step forward and has given good yield improvement in diseased fields in many parts of the world. The original variety and subsequent improved versions continued to offer good performances for about a decade, after which it was surpassed by other hybrids derived in part from the Rizor itself. Further progress in terms of sugar production became possible in 1986, when the Holly monogerm lines were released in USA and Europe. In spite of the incomplete information about the genealogy of the first resistant materials,many evidences and the molecular analyses on the different genotypes suggest a possible common progenitor and lineage. The resistant cultivars have kept the yield at an adequate level, allowing cultivation to continue in countries where the disease has reached epidemic proportions. The case of rhizomania resistance in sugar beet can therefore be considered as one of the most important achievements in plant breeding.