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Publication #HS930

Potato Physiological Disorders—Growth Cracks1

L. Zotarelli, C. Hutchinson, S. Byrd, D. Gergela, and D. L. Rowland2

Growth cracking is an external noninfectious physiological disorder of the potato tuber in which the tuber splits while growing. The split heals but leaves a fissure in the tuber. Growth cracks generally start at the bud or apical end of the potato and can extend lengthwise. They vary in severity from a surface abrasion to a split through the tuber, depending on the stage of growth during which the initial cracking occurred (Figure 1).

Figure 1. 

Moderate (left) and severe (right) growth cracks in 'Atlantic'


Credit:

C. Hutchinson


[Click thumbnail to enlarge.]

Even though cracking does not usually predispose the tuber to rotting, growth cracks can negatively impact potato tuber quality. Growth cracks make fresh-market tubers unattractive. Severe growth cracks can even impact the quality of chip potatoes and affect processing (Figure 2).

Figure 2. 

Examples of severe growth cracks in 'Atlantic' that would reduce marketability.


Credit:

C. Hutchinson


[Click thumbnail to enlarge.]

Growth cracks form due to fluctuating environmental conditions, such as uneven soil moisture, soil and air temperature, and rapid water uptake and tuber growth (Hiller and Thornton 2008; Jefferies and MacKerron 1987). Growth cracks increase when relatively poor growing conditions are rapidly followed by relatively good growing conditions, such as prolonged moisture stress or high temperatures followed by excessive irrigation or rainfall (Selman et al. 2008). The severity of growth cracks is increased in plants that are widely spaced or planted at unusually low densities, and it is also made worse if fertilizer is applied unevenly. This is especially true when nitrogen fertilizer is applied in excess or when the application of nitrogen fertilizer is not properly timed. There is also a link between low boron levels in the soil and increased intensity of growth cracks (Hiller, Koller, and Thornton 1985). There is evidence that potato plants infected with viruses that exhibit mosaic symptoms (mottling coloration on the leaves) have increased incidence of growth cracks (Carnegie and McCreath 2010). There are differences in the susceptibility of potato varieties to growth cracks. 'Atlantic', the most widely grown potato for chip processing in Florida, and 'Red Lasoda', a common variety for table-stock, are relatively susceptible to the disorder. The Florida Potato Variety Trials have shown that most of the standard varieties grown in Florida (e.g., 'La Chipper', 'Harley Blackwell', etc.) are not susceptible in most years, but weather has influenced the incidence, especially in hot and wet years (Figure 3).

Figure 3. 

Example of severe growth cracks in baking potato variety


Credit:

L. Zotarelli


[Click thumbnail to enlarge.]

To reduce the incidence of growth cracks, maintain proper soil moisture during the season. This is especially important during the bulking stage when the plants are large and tubers are rapidly expanding. In Florida, this stage occurs late in the season when air and soil temperatures increase quickly. Large plants and expanding tubers require more water to maintain good growth. Other recommendations to reduce the incidence of growth cracking include spacing plants uniformly, applying irrigation evenly to keep soil moisture levels consistent, and ensuring accurate application amounts and fertilizer placement.

The only recourse when the incidence of severe growth cracks is high is to select out tubers with severe growth cracks prior to packing and/or shipping.

Further Information

Bohl, W. H., and S. B. Johnson, eds. 2010. "Commercial Potato Production in North America: The Potato Association of America Handbook." The Potato Association of America. http://potatoassociation.org/documents/A_ProductionHandbook_Final_000.pdf.

Zotarelli, L., P. D. Roberts, P. J. Dittmar, S. E. Webb, S. A. Smith, B. M. Santos, and S. M. Olson. 2012. Potato Production in Florida. HS733. Gainesville: UF/IFAS. http://edis.ifas.ufl.edu/cv131.

References

Carnegie, S. F., and M. McCreath. 2010. "Mosaic Virus Symptoms in Potato Crops and the Occurrence of Growth Cracking in Tubers." Potato Research 53(1): 17–24.

Hiller, L. K., D. C. Koller, and R. E. Thornton. 1985. "Physiological Disorders of Potatoes." In Potato Physiology, edited by P.H. Li, 389–455. New York: Academic Press.

Hiller, L.K., and R. E. Thornton. 2008. "Managing Physiological Disorders." In Potato Health Management: Plant Health Management Series, edited by D. A. Johnson, 235–245. St. Paul, MN: The American Phytopathological Society.

Jefferies, R. A., and D. K. L. MacKerron. 1987. "Observations on the Incidence of Tuber Growth Cracking in Relation to Weather Patterns." Potato Research 30(4): 613–623.

Selman, L., N. Andrews, A. Stone, and A. Mosley. 2008. "What's Wrong with My Potato Tubers? Diagnosing Tuber Abnormalities in Western Oregon and Washington." Oregon State University Extension Service and Western Region Sustainable Agriculture Research and Education. Accessed January 8, 2012. http://extension.oregonstate.edu/catalog/pdf/em/em8948-e.pdf.

Footnotes

1.

This document is HS930, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date July 2003. Revised May 2012. Reviewed March 2015. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

L. Zotarelli, assistant professor, Horticultural Sciences Department; C. Hutchinson, former associate professor, Horticultural Sciences Department; S. Byrd, graduate student, Agronomy Department; D. Gergela, research coordinator, Florida Partnership for Water, Agriculture & Community Sustainability at Hastings; and D. L. Rowland, associate professor, Agronomy Department, UF/IFAS Extension, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.