Halterman Lab Blog

How to Build a Better Potato


On February 21st, Dr. Halterman, along with fellow USDA/ARS scientists Dr. Shelley Jansky and Dr. Paul Bethke and technician Holly Reuss, traveled to Stevens Point, WI to meet with 7th and 8th graders from around Wisconsin for the STEM (Science, Technology, Engineering and Mathematics) Career Day for Girls.  The event showcases STEM career professionals from throughout Wisconsin. Students engage in hands-on workshops (and learn the many career paths available with an education in STEM). The conference includes exhibits, a keynote presentation, and three, one-hour workshops. 

Our presentation was entitled “How to Build a Better Potato” and we discussed a couple of topics that we are very familiar with - disease resistance and potato storage.  While these are only two aspects of breeding that we are interested in, they provided hands-on opportunities for the students.  Dr. Halterman led a discussion of virus resistance in potato and why it is important to be able to identify whether plants are infected with a virus.  Students were able to view plants with and without the Potato Virus Y virus and predicted the presence of PVY in unknowns.  Leaflets of the plants were then used in a rapid diagnostic test kit to determine whether or not the unknowns contained virus and whether their observations correlated with the results.

Drs. Jansky and Bethke led a discussion of potato storage and why it is important to store potatoes under conditions that limit respiration and disease (cold) and how this contrasts with the need to keep sugar levels in the potatoes low (potato starches are converted to sugar under cold conditions).  High sugar levels in potatoes lead to dark colored chips and fries, which are frowned upon by the potato production industry.  Using potatoes that had been stored in warm and cold conditions, the students first used glucose test strips to determine the sugar levels of each potato.  Then, they placed a slice of each potato into hot oil to make chips.  The potatoes with high sugar levels (cold stored) turned dark brown, while the low sugar potatoes (warm stored) stayed a light golden color after frying.  The students were then each given an “unknown” and predicted the potato chip color using the glucose test strips and tested their hypothesis by frying them.