Effect of beet yellowing viruses on light interception and light use efficiency of the sugarbeet crop

Abstract

We monitored the development of ground cover by green and yellow leaves in healthy sugarbeet and in sugarbeet infected with beet mild yellowing virus (BMYV) and beet yellows virus (BYV). Infection with BMYV reduced light interception by green foliage by up to 40%, due to leaf yellowing. Infection with BYV reduced light interception by green leaves by up to 55%, due to 50% cover by yellow leaves and decreased total (green + yellow) ground cover. Dry matter accumulation was regressed against cumulative light interception by green foliage to estimate light use efficiency of the visually unaffected foliage. Healthy and BMYV infected sugarbeet had similar light use efficiencies, indicating that yield loss can be entirely attributed to interception of solar energy by yellow, unproductive foliage. Infection with BYV decreased light use efficiency. The results show that yield losses caused by yellowing viruses can be assessed by monitoring the disease-induced reduction in ground cover by green leaves.