Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: SUCROSE ACCUMULATION AND RETENTION IN SUGARBEETS Title: Postharvest respiration rate and sucrose concentration of Rhizoctonia-infected sugarbeet roots

Authors
item Campbell, Larry
item Windels, Carol -
item Fugate, Karen
item Brantner, Jason -

Submitted to: Sugarbeet Research and Extension Reports
Publication Type: Proceedings
Publication Acceptance Date: January 18, 2013
Publication Date: February 11, 2013
Citation: Campbell, L.G., Windels, C., Fugate, K.K., Brantner, J. 2013. Postharvest respiration rate and sucrose concentration of Rhizoctonia-infected sugarbeet roots. 2012 Sugarbeet Research and Extension Reports. 43:114-120.

Interpretive Summary: The negative impact of Rhizoctonia crown and root rot (RCRR) on postharvest respiration, sugar concentration, and beet quality for roots with disease ratings of 2 or 3 is relatively small and would have only a small, and maybe immeasurable, effect on factory efficiency when mixed with healthy roots. A high frequency of roots with a disease rating of 5 will likely slow processing and reduce the quality of the sugar produced. The elevated respiration rate of roots with a disease rating of 5, and to a lesser extent 4, indicates that the sugar loss during storage will be relatively high and the temperature increase caused by the high respiration rate may increase losses in nearby healthy roots, if the heat is not dissipated. The response of stored roots with a given disease rating, relative to healthy roots of the same variety, does not appear to be influenced by the resistance level of the variety. However, it is important to note that resistant varieties frequently will have considerably fewer roots with disease ratings of 4 or above than susceptible varieties, when conditions are favorable for disease development. Thus planting resistant varieties is an effective strategy for reducing postharvest storage losses from severe RCRR infection. Differences in sucrose concentration, quality components, and respiration rates from year to year and differences in the magnitude of the contrast between healthy roots and roots with serve symptoms indicates that environmental conditions during the growing season influences the impact of RCRR on postharvest losses.

Technical Abstract: The negative impact of Rhizoctonia crown and root rot (RCRR) on postharvest respiration, sugar concentration, and beet quality for roots with disease ratings of 2 or 3 is relatively small and would have only a small, and maybe immeasurable, effect on factory efficiency when mixed with healthy roots. A high frequency of roots with a disease rating of 5 will likely slow processing and reduce the quality of the sugar produced. The elevated respiration rate of roots with a disease rating of 5, and to a lesser extent 4, indicates that the sugar loss during storage will be relatively high and the temperature increase caused by the high respiration rate may increase losses in nearby healthy roots, if the heat is not dissipated. The response of stored roots with a given disease rating, relative to healthy roots of the same variety, does not appear to be influenced by the resistance level of the variety. However, it is important to note that resistant varieties frequently will have considerably fewer roots with disease ratings of 4 or above than susceptible varieties, when conditions are favorable for disease development. Thus planting resistant varieties is an effective strategy for reducing postharvest storage losses from severe RCRR infection. Differences in sucrose concentration, quality components, and respiration rates from year to year and differences in the magnitude of the contrast between healthy roots and roots with serve symptoms indicates that environmental conditions during the growing season influences the impact of RCRR on postharvest losses.

Last Modified: 11/26/2014
Footer Content Back to Top of Page