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United States Department of Agriculture

Agricultural Research Service

Research Project: SUCROSE ACCUMULATION AND RETENTION IN SUGARBEETS

Location: Sugarbeet and Potato Research

Title: Postharvest respiration rate and sucrose content 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 17, 2011
Publication Date: March 14, 2011
Citation: Campbell, L.G., Windels, C.E., Fugate, K.K., Brantner, J. 2011. Postharvest respiration rate and sucrose content of Rhizoctonia-infected sugarbeet roots. 2010 Sugarbeet Research and Extension Reports. 41:167-172. Available: http://www.sbreb.org/research/prod/prod10/CampbellPostHarvestRhizRoots2010.pdf.

Interpretive Summary: Rhizotonia crown and root rot of sugarbeet, caused by Rhizoctonia solani AG 2-2, is increasing in Minnesota and North Dakota. As the disease increases in prevalence and severity, more diseased roots are being stored in piles where they affect storability and postharvest quality. The objective of this research was to determine the impact of Rhizotonia crown and root rot on postharvest respiration rate, sucrose concentration, and processing quality of three sugarbeet varieties differing in resistance to Rhizotonia crown and root rot. Harvested roots, if not frozen, respire constantly to provide the energy and products needed to maintain the integrity of the root, heal wounds incurred during harvest and piling, and protect against pathogens. Respiration typically accounts for as much as 80% of the sugar lost during storage (Campbell and Klotz, 2006b). Invert sugar is a product of sucrose breakdown that reduces processing efficiency. Respiration rates 30. 60, and 90 DAH increased as disease severity increased. Respiration rates of roots with a disease rating of four (0 = no disease to 7=very severe) were slightly elevated and differences among roots with ratings of three or lower were relatively small. The respiration rate of roots with severe Rhizotonia crown and root rot (disease rating = 5) was relative high and constant during the 90 days in storage. Sucrose concentration 30 days after harvest decreased from 17.3% to 14.3% as disease rating increased from 0 to 5. The increase in invert sugar concentration accompanying an increase in Rhizotonia crown and root rot severity suggests that a high frequency of roots with severe disease symptoms will reduce factory efficiency and the quality of the sugar produced.

Technical Abstract: Rhizotonia crown and root rot of sugarbeet, caused by Rhizoctonia solani AG 2-2, is increasing in Minnesota and North Dakota. As the disease increases in prevalence and severity, more diseased roots are being stored in piles where they affect storability and postharvest quality. The objective of this research was to determine the impact of Rhizotonia crown and root rot on postharvest respiration rate, sucrose concentration, and processing quality of three sugarbeet varieties differing in resistance to Rhizotonia crown and root rot. Harvested roots, if not frozen, respire constantly to provide the energy and products needed to maintain the integrity of the root, heal wounds incurred during harvest and piling, and protect against pathogens. Respiration typically accounts for as much as 80% of the sugar lost during storage (Campbell and Klotz, 2006b). Invert sugar is a product of sucrose breakdown that reduces processing efficiency. Respiration rates 30. 60, and 90 DAH increased as disease severity increased. Respiration rates of roots with a disease rating of four (0 = no disease to 7=very severe) were slightly elevated and differences among roots with ratings of three or lower were relatively small. The respiration rate of roots with severe Rhizotonia crown and root rot (disease rating = 5) was relative high and constant during the 90 days in storage. Sucrose concentration 30 days after harvest decreased from 17.3% to 14.3% as disease rating increased from 0 to 5. The increase in invert sugar concentration accompanying an increase in Rhizotonia crown and root rot severity suggests that a high frequency of roots with severe disease symptoms will reduce factory efficiency and the quality of the sugar produced.

Last Modified: 9/29/2014
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