- Ph.D. University of California at Davis, Plant Physiology
- A.B. University of Chicago, Biology
Apple Fruit Texture; Harvest and Postharvest Uses of Near Infrared Spectroscopy; Potato Anthocyanin Genomics; Honeycrisp Apple Storage Disorders;
My lab is trying to answer the following questions:
- How do some apple varieties maintain crispness?
- How do environmental conditions affect the likelihood that apples will develop storage disorders?
- What is near infrared spectroscopy detecting in senescing fruit?
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’ fruit. A lot of people like crisp apples, so ‘Honeycrisp’ has been used in many apple breeding programs, and many of its genes have been incorporated into current and future new releases. The mechanisms by which ‘Honeycrisp’ maintains its crispness is one focus of my lab’s work. We measure fruit texture by various means and use 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.
Environmental Effects on Apple Storage Disorders
Fruit of ‘Honeycrisp’ and some of its progeny can develop postharvest storage disorders, such as soft scald and internal browning. These disorders exhibit tree-to-tree, orchard-to-orchard, and year-to-year variation, so they are a challenge to study! How do environmental conditions and tree position affect the likelihood that individual fruit will develop disorders?
Near Infrared Spectroscopy
Engineers have shown that near infrared spectroscopy has many potential uses, such as estimating dry matter, detecting bruising and internal discoloration, and approximating soluble sugar content of fruit. We’re interested in determining the use of near infrared spectroscopy across multiple genotypes and environments, validating its measurements in fruit, and finding new harvest and postharvest applications. For example, we want to know how well it discriminates between insect-infested and uninfested fruit, and whether it can be used to predict likelihood of fruit developing storage disorders.
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, and testing new ways for them to deal with increasingly erratic weather conditions.
Extension work is collaborative, so in cooperation with other extension personnel, nonprofit organizations, and grower groups, I help develop and provide education to Minnesota fresh market fruit & vegetable growers through individual communication, newsletter articles, and presentations. I work with the Minnesota Fruit & Vegetable Growers Association, the Minnesota Apple Growers Association, various independent farms, and the coalition that organizes the Emerging Farmers Conference.
Specific Extension projects of mine include:
- 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 can small-acreage farms adopt that would be the most cost-effective and lead to improved food safety? How can we make recordkeeping less onerous for everybody?
- Testing new production methods to help deal with increasingly erratic weather – many Minnesota farmers have adopted high tunnels to help extend the growing season into cold springs. However, summers are getting hotter, especially at night. Can we use shade and other materials to grow cold-season vegetables into the summer? What vegetable varieties and production practices are best suited to unpredictable weather conditions?
- Xu, Y, T Ma, NP Howard, C Chen, CBS Tong, G Celio, JR DeEll, RE Moran. 2017. Microstructure of soft scald in ‘Honeycrisp’ apples. J Amer Soc Hort Sci 142:1-6. doi: 10.21273/JASHS04250-17.
- Tong, C, H-Y Chang, J Boldt, Y Ma, JR DeEll, R Moran, G Bourgeois, D Plouffe. 2016. Diffuse Flesh Browning in ‘Honeycrisp’ Apple Fruit is Associated with Low Temperatures during Fruit Growth. HortScience 51:1256-1264; doi:10.21273/HORTSCI11179-16.
- 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.