 | Cindy Tong
Post-Harvest Physiology
Associate Professor
Phone: 612.624.3419
Email: c-tong@umn.edu
My area of expertise is
POSTHARVEST PHYSIOLOGY. Half of my job is helping fresh market fruit and
vegetable growers with their harvest, handling, and storage problems. The other
half of my job is research. My lab utilizes biochemical and molecular methods to
understand how some apple fruit maintain their crispness and what
regulates the color of red potatoes.
Extension
Programming
In cooperation with other extension
personnel, I develop and conduct educational programs for Minnesota growers on vegetable crops.
Through our efforts, we try to keep Minnesota
fresh market produce operations profitable. Part of helping growers be
profitable is finding incentives to getting people to eat fruits and
vegetables, so I also work with kids in a school in North
Minneapolis and am interested in local food marketing issues.
Past projects have included:
- planning the annual Upper Midwest Fruit & Vegetable Growers
Association meeting
- writing articles for the Minnesota Fruit &Vegetable Growers
Association newsletter
- producing Web-based information for vegetable growers with help
from other vegetable specialists and University of Minnesota
Extension Service personnel
- researching storage, handling, and quality problems of
Minnesota-grown vegetables and fruit (especially the 'Honeycrisp' apple).
Specific projects have included trying to
figure out what causes soft scald in 'Honeycrisp' apples, developing a
demonstration carrot storage facility and testing the use of a biocontrol agent
for silver scurf in muck soils.
Graduate students generally are not involved
in Extension Programming unless their research on fruits and vegetables are of
interest to farmers.
Research Projects
My lab is trying to answer the following
questions:
- What limits red coloration in potato tuber periderm
- How do some fruit maintain crispness?
Red Potatoes
Red potatoes are an important crop in Minnesota. A potato with
a bright, red skin color is sought after by growers and consumers. We are
trying to help develop a bright red potato that keeps its skin color throughout
storage. The chemical compounds responsible for the red color in potato peel
are called anthocyanins. Much is known about the biochemistry and molecular
genetics of anthocyanin synthesis from work done in snapdragon and petunia
petals, and maize leaves and kernels. Many of the structural genes, and some
transcriptional regulators (genes controlling the expression of the structural
genes) have been cloned from those species. My lab clones these genes from
potato periderm and studies how plant growth regulators and environmental
conditions affect their expression.
Limitations during growth
We've learned that 'Norland' tubers make
anthocyanins very early, when they are basically swollen stolon tips. After
that, accumulation per given surface area decreases as the tuber grows. We are
trying to determine the biochemical and genetic reasons why accumulation slows
as the tuber grows.
Fruit Texture
Crispness in apples is a sought-after
consumer trait. We want to know why some apple varieties, like 'Honeycrisp'
stay crisp for a long time after harvest. Knowing this may help us slow the
softening process in apple varieties that don't maintain their crispness, as
well as develop new varieties that stay crisp through winter storage. We have
compared changes in texture of 'Honeycrisp' and 'Macoun' apples during storage.
'Honeycrisp' is an apple variety developed in Minnesota. Its fruit remain crisp and juicy
through months of cold storage under normal air atmosphere. There is a good
correlation between turgor pressure and firmness in these apples, and a weaker
correlation between arabinose content and crispness. 'Macoun' apples lose
their crispness early after harvest. Whether apple fruit lose their
crispness does not correlate well with activities of cell wall degrading
enzymes. However, we have recently discovered a good correlation
between maintenance of crispness and part of the genetic sequence of one
of the cell wall enzymes. We are interested in studying this correlation
in multiple apple genotypes and determining how this sequence affects the
phenotype.
Selected
References
- 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
- 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.
- 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
- 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
- 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
- Rosen, C.J. and C.B.S. Tong. 2001 Yield, dry
matter partitioning, and storage quality of hardneck garlic as affected by soil
amendments and scape removal. HortScience 36:1235-1239.
- 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.
- 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.
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