Abstract
BNYVV concentration in the tap roots of sugar beet varieties grown in rhizomania‐infested fieldsDuring plant development, the BNYVV concentration in several commercially available rhizomania‐tolerant sugar beet varieties and one susceptible variety was examined as an index of the intensity of infection. The root weight, sugar content and sugar yield of the same varieties in fields naturally infested with rhizomania were also measured.Significant negative correlations were found between the average virus concentration in the tap root and yield parameters in infested fields. These were largely independent of the growth stage of beet plants used for virological investigations. However, the negative correlations between virus concentration and yield were not significant if rhizomania‐tolerant varieties only were compared.The possibility that virus concentration might be used as a criterion for selection in addition to yield performance is discussed. This may lead to selection that is targeted more directly at rhizomania resistance and thereby accelerate breeding work.