Spudman November/December 2022 - 36

the seed industry. It would help
certification agencies accurately test
for viruses to ensure high quality
seed is available for producers, as well
as help seed growers gain access to
markets in various locations.
Research: Late blight continues to
negatively impact potato growers due
to yield losses and expensive control
measures. While the pathogen can
be well-controlled with fungicides,
the continued use of chemicals can
be expensive both in cost and time,
detrimental to the health of humans
and the environment, and can lead
to resistant strains of the pathogen
Phytophthora infestans. Resistance
genes provide another avenue to
prevent disease, while also reducing the
use of fungicides.
The late blight resistance gene, RB
Peyton Sorenson
Bio: I am currently a research
laboratory technician at the University of
Illinois Urbana-Champaign working on
the Realized Increased Photosynthetic
Efficiency (RIPE) project. I completed
both my bachelor's degree in horticulture
and my master's degree in plant breeding
and plant genetics at the University of
Wisconsin (UW) - Madison.
(Rpi-blb1), has been shown to provide
durable, broad-spectrum resistance
to most strains of P. infestans. For
my master's research, we focused on
breeding this gene into the University
of Wisconsin Potato Breeding program
germplasm. We primarily used marker
based selection, which relies on the use
of genetic markers to determine if a
gene is present in an individual.
The tetraploid nature of potatoes
makes breeding more complicated
than it is for a diploid species. For
example, tetraploids produce more
genotypic combinations than if two
diploids were crossed. Breeders must
then screen larger populations to find
desirable genotypes than they would
have to for a diploid population.
High-throughput methods are
necessary to genotypically screen
these large populations for locating
individuals with genes of interest.
Locating individuals homozygous for
a gene is more desirable, as they should
always produce offspring with the
gene. Achieving homozygosity is more
difficult in a tetraploid than a diploid, as
four copies of the gene must be present
rather than two. Knowing the copies
of a gene can be advantageous for the
breeder, as they can choose to cross
individuals with higher copy numbers
to more quickly reach homozygosity.
While an effective genetic marker
for detecting RB has been created
and published, it does not tell the
user the RB copy number (only if it
is present or not), and it is based on
a lower-throughput platform. To be
able to create a higher-throughput
genetic marker that could be used for
determining the copy number of RB,
we decided to use the Kompetitive
Allele Specific PCR (KASP) platform.
KASP markers allow users to determine
the copy number of a gene of interest,
and the results from 20 to over 1,500
samples can be visualized using a
compatible thermocycler in a matter
of hours.
To design this marker, we had the
genomes sequenced of two UW lines
with RB and used previously published
sequencing data of 23 commonly used
breeding varieties without RB. Using
the sequencing data, we located a
EXCEPTIONAL QUALITY SEED
POTATOES SINCE 1960.
Our isolated northern location along with our group of 10 experienced
growers have been producing exceptional seed potatoes with increased
energy and the lowest possible disease levels for over 50 years.
Our longevity and historical performance have made us a valued
resource and seed potato supplier to growers across North America
and the world.
With over 100 varieties including main crop and specialty selections,
we invite you to give us a call to discuss how we can help you make
this growing season the best one yet.
Contact Darcy Olson for the latest info on availability of varieties & generations
Email: darcyo@epg.ab.ca * Toll Free: 1 (800) 362-9791 * Ph: (780) 447-1860
Edmonton Potato Growers, 12220 - 170 Street, Edmonton, AB T5V 1L7
36
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Spudman November/December 2022

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