- Ph.D. University of California at Davis, Plant Physiology
- A.B. University of Chicago, Biology
Apple Fruit Texture; Potato Anthocyanins; Honeycrisp Apple Storage Disorders
My lab is trying to answer the following questions:
- How do some fruit maintain crispness?
- What limits red coloration in potato tuber periderm?
Apple Fruit Crispness
If you’ve ever tasted a ‘Honeycrisp’ apple, you know that it’s got a crisp texture. The ability to remain crisp is one of the best features of ‘Honeycrisp’. Because people like crisp apples, ‘Honeycrisp’ has been used in many apple breeding programs, so some of its genes may be incorporated into future releases. The mechanisms by which ‘Honeycrisp’ maintains its crispness is one focus of my lab’s work. We are now using next generation sequencing to better pinpoint genes that may be involved in 'Honeycrisp' crispness maintenance. We are also using a full-sib breeding population to study the expression of these genes.
The coloration of red potato tubers is due to pigments called anthocyanins, which can have complex chemistries. Based on studies using the variety Norland, we know that anthocyanins are synthesized very early in potato tuber development. As the tuber expands, the anthocyanins present in the skin get diluted. Why does the potato stop synthesizing anthocyanins as the tuber enlarges?
The Norland variety naturally produced a mutant with pinker tubers, named Red Norland. Red Norland gave rise to a variety with darker tubers, called Dark Red Norland. We are using next generation DNA sequencing to determine how anthocyanin genes have changed when Norland mutated into its color sports Red Norland and Dark Red Norland.
The majority of Minnesota’s vegetable farmers have small, diverse, retail-based operations with few employees. About 75 % of them grow 10 or more vegetables on 10 acres or less, with help from fewer than 6 employees, and sell primarily through direct marketing. My Extension work is focused on helping Minnesota’s farmers be profitable by helping them with any storage or postharvest handling problems they may have.
Extension work is collaborative, so in cooperation with other extension personnel, nonprofit organizations, and grower groups, I help develop and conduct educational programs for Minnesota fresh market fruit & vegetable growers. I work with the Minnesota Fruit & Vegetable Growers Association, the Minnesota Apple Growers Association, various independent farms, and the coalition that organizes the Immigrant and Minority Farmers Conference.
I also perform research on:
- Honeycrisp apple storage disorders — Although a variety with exceptional crispness, Honeycrisp fruit can develop postharvest storage disorders, such as soft scald and internal browning. These disorders exhibit tree-to-tree, orchard block-to-block, orchard-to-orchard, and year-to-year variation, so they are a challenge to study!
- Best postharvest storage practices to help prevent food safety outbreaks — Americans are eating more fresh fruits and vegetables, which is good for their health, but with increased consumption, outbreaks of Salmonella and E. coli associated with these foods is of greater concern. What improvements in practices on small-acreage farms would be the most cost-effective and lead to improved food safety?
- Tong, C., S.J. McKay, J.J. Luby, R. Beaudry, C. Contreras, J.F. Nock, and C.B. Watkins. 2013. Using mixed-effects models to estimate the effect of harvest date and its interactions with post-harvest storage regime on apple fruit firmness. Journal of Horticultural Science and Biotechnology 88: 29-36.
- Trujillo, D., H. Mann, and C. Tong. 2012. Examination of expansin genes as related to apple fruit crispness. Tree Genetics and Genomes 8:27-38, doi:10.1007/s11295-011-0417-z.
- Mann, H.S., J.J. Alton, SH Kim, and C.B.S. Tong. 2008. Differential Expression of Cell-wall–Modifying Genes and Novel cDNAs in Apple Fruit During Storage. J. Amer. Soc. Hort. Sci. 133: 1-6
- Tong, C.B.. D.S. Bedford, J.J. Luby, F.M. Propsom, R.M. Beaudry, J.P. Mattheis, C.B. Watkins, and S.A. Weis. 2003. Location and temperature effects on soft scald in 'Honeycrisp' apples. HortScience 38:1-3
- El-Shiekh, A.F., C.B.S. Tong, J.J. Luby, E.E. Hoover, and D.S. Bedford. 2002. Storage potential of cold-hardy apple cultivars. J. Amer. Pomol. Soc. 56:34-45
- Tong, C., D. Krueger, Z. Vickers, D. Bedford, J. Luby, A. El-Shiekh, K. Shacker, and H. Amadi. 1999. Comparison of softening-related changes during storage of 'Honeycrisp' apple, its parents, and 'Delicious'. J. Amer. Soc. Hort. Sci. 124: 407-415.
- Roe, M.R., J.L. Carlson, T.M. McManimon, A.D. Hegeman, and C.B.S. Tong. 2014. Differential accumulation and degradation of anthocyanins in Red Norland periderm is dependent on soil type and tuber storage duration. Amer J Potato Res, in press.
- Fixen, K.R., S. C. Thomas, and C. B.S. Tong. 2012. Blue light inhibition of tuberization in a day neutral potato. J. Plant Growth Regul. 31:342-350, (DOI) 10.1007/s00344-011-9242-8.
- Rosen, C.J., J.A. Roessler, S.Engelman, P.D. Petracek, and C.B.S. Tong. 2009. 2,4-Dichlorophenoxyacetic acid Increases peonidin derivatives in Red Norland periderm. Amer. J. Potato Res. 86: 15-24. (published online in 2008; DOI: 10.1007/s12230-008-9055-x)
- Keifenheim, D.L.., A.G. Smith, and C.B.S. Tong. 2006. Cloning and accumulation of anthocyanin biosynthesis genes in developing tubers. Amer. J. Potato Research 83:233-239.
- Andersen, A.W., C.B.S. Tong and D. Krueger. 2002. comparison of periderm color and anthocyanins of four red potato varieties. Amer. J. Potato Res. 79: 249-253
- Hung. C-Y., J.R. Murray, S.M. Ohmann, and C.B. Tong. 1997. Anthocyanin accumulation during Solanum tuberosum development. J. Amer. Soc. Hort. Sci. 122:20-23.