Water status but not mild and cold temperatures affect harvest damage susceptibility and tissue integrity of sugar beet (<i>Beta vulgaris</i>) roots

Abstract Sugar beet root damage at harvest promotes sucrose losses of circa 0.1 – 0.4 % day –1 in storage. However, root response to environmental stresses at harvest and their consequential rates of damage are not known. We investigated the effects of temperature and water stress at harvest on root resilience to damage and tissue strength. Water (irrigated to field capacity and non-irrigated) and temperature (cold and mild) treatments were imposed on physiologically mature sugar beet plants for seven weeks prior to and for three days after harvesting, respectively. Water status at harvest significantly affected relative water content (RWC) ( p &lt; 0.001), root weight ( p &lt; 0.001) and root width ( p &lt; 0.001). RWC was positively correlated to surface damage ( R 2 = 0.43, p = 0.02), root tip damage ( R 2 = 0.42, p = 0.03), tissue compression ( R 2 = 0.41, p = 0.05) and tissue puncture ( R 2 = 0.46, p = 0.01). Tissue damage was not affected by root tissue temperature of 4 °C compared to 12 °C. We conclude that sugar beet damage at harvest is not influenced by root temperatures over the range commonly observed in the UK and temperate production areas. However, higher water status at harvest, such as would be observed in a wet season, increases root tip and surface damage. These findings will help to inform optimum harvesting conditions to minimize sugar loss from the sugar beet crop.