Spudman November/December 2022 - 35

There isn't a lot of information
about Spongospora subterranea, so one
objective of my project is to sequence
its genome. I'm accomplishing this by
extracting DNA from the resting spores
of the pathogen and then using PacBio
sequencing to assemble its genome.
However, a promising management
strategy for powdery scab is to breed
resistant cultivars, so my second
objective is to identify informative
markers in the potato's genome that
are associated with resistance. Earlier
this year, I screened several promising
potato cultivars in the greenhouse for
resistance by intentionally giving them
powdery scab and observing which lines
had the fewest symptoms. I found that
Summit Russet and Mesa Russet were
two cultivars that were highly resistant.
I'm now using these results to move
forward in genotyping genetic variation
between resistant and susceptible
varieties and narrowing down what
markers are associated with powdery
scab resistance.
University of Idaho and plan to finish in
May of 2023.
Research: Starting with high-quality,
certified seed is the key to any successful
cropping system. Quality issues and
virus diseases can limit yield potential.
Potatoes undergo a rigorous process
to become certified seed to ensure that
growers can start off strong.
Several viruses such as potato
virus Y (PVY) and potato leaf roll virus
(PLRV) can be transmitted through
the seed piece of a potato and infect
the subsequent plant. To ensure low
levels of virus in seed, certification
agencies conduct a postharvest test
on each seed lot. Postharvest testing
is conducted shortly after harvest
and requires actively growing tissue
to complete. This is a major issue for
certification agencies since potatoes
are in a state of dormancy where they
will not sprout, even in favorable
growing conditions. Current methods
to break dormancy are challenging and
time consuming.
The goal of this project was to
Nathan Gelles
Bio: I completed my bachelor of
science degree in plant sciences at the
University of Idaho and started work
for an agricultural supply company in
agronomy. My passion for agriculture
and learning was expanding, which
led me to pursue higher education. I
received the opportunity to become a
master's student in plant sciences under
the supervision of Dr. Nora Olsen at the
explore alternative methods to initiate
sprouting soon after harvest. Various
treatments were tested, ranging from
cold and heat shock treatments to
dipping in growth regulators and sugar
water solutions, yielding little success.
To everyone's surprise, application
of cool aerosol smoke worked
consistently well at promoting early
sprout development.
A custom-built smoke generator
burned plant-based pellets and injected
smoke into a custom application
chamber. The smoke treatment alone
provided very promising results in
initiating and promoting earlier sprout
development. However, a combination
treatment, smoke followed by a dip in
gibberellic acid, produced impressive
results in promoting tubers to sprout
soon after harvest.
Treatments have been applied
to several commercially grown
potato varieties with varying levels
of dormancy. The smoke-based
treatments consistently promoted
sprout development and then increased
the number and size of sprouts of each
variety evaluated.
Effective methods to break tuber
dormancy would be beneficial to
Spudman * November/December 2022
35
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Spudman November/December 2022

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