2021 marked the production of the 100th certified seed potato crop in Montana. The journey to this milestone involved dedication, hard work, and a strong dose of innovation both on the farm and in the lab.
In the beginning, a typical seed potato farm might have eight to 10 acres, and the predominant variety was Netted Gem. Potatoes were planted by hand or with a one-row planter, dug with a single blade, then picked and bagged by hand. A good yield was around a 100 sacks to the acre.
Today’s average farm size is closer to 500 acres, with yields over 400 sacks per acre common. Yesterday’s farmers would brag amongst themselves about who could plant the straightest rows, while today’s fields are planted utilizing GPS. Mechanization continues to reduce the need for the backbreaking manual labor that many of our older farmers experienced. The pickers on grading lines have been largely replaced by clod hoppers and vacuum separators. Storage cellars with computer-controlled ventilation systems ensure the hard work invested in growing and harvesting the crop will result in a quality, salable product the next spring. Irrigation is much more efficient, utilizing center pivots rather than wheel or hand lines, and the systems are monitored and controlled by farmers using customized apps on their cell phones.
Insect and disease control has evolved to a more integrated approach, using information on pathogen biology and the environment to more accurately address pest management issues with the least toxic chemistry. There are many stories about seed treatments using mercury, and attacking aphids and other insects with insecticides that were so toxic, workers feared for their lives if they were caught in a field being sprayed. Today’s farmers utilize chemicals that more specifically target pests with less impact on beneficial insects, and schedule sprays based on biology of the pest and environmental conditions. Nontoxic mineral oil has become the first line of defense to limit aphid transmission of mosaic viruses, and has reduced the impact of that disease on certified seed potatoes while reducing the amount of insecticides sprayed.
Due to the nature of propagating potatoes from potatoes, Montana’s first potatoes produced for seed had a high incidence of disease. In 1927, greenhouse indexing was introduced to eliminate diseased or off-type seed. One tuber from an individual hill was grown in the greenhouse during the winter, and the sister tubers from that hill were retained if the test tuber was healthy, or discarded if disease or an off-type was observed.
This was the state of the art until 1966, when Dr. Richard Hamilton introduced meristem culture to the Montana State University Seed Potato Certification program. This allowed the program to propagate disease-free potatoes in the lab and distribute them to Montana seed potato growers. His replacement, Dr. Jim Shepard, then developed the radial diffusion assay, which was capable of testing hundreds of thousands of plants for PVX and, later, PVY. The deployment of this technique put the Montana State University Potato Lab at the forefront of utilizing laboratory-based pathogen detection methods to aid growers in the production of disease-free seed. With the arrival of Dr. Mike Sun in 1978, a new antibody-based test—ELISA—was adopted, which improved the efficiency and accuracy of virus testing even more, and continues to be the workhorse of the MSU Potato Lab for detecting viruses in both the summer testing program and the post-harvest grow-out in Hawaii.
A new sample-pressing system deployed by MSU Potato Lab supervisor Steve Hystad in the summer of 2021 reduced the lab staff required to process samples by a third. In addition to ELISA for detecting viruses in leaves, we also use highly sensitive PCR to detect viruses in dormant tubers. This is the same method used to detect COVID-19 and other human pathogens. The Montana program integrates dormant tuber testing as a complement to the winter grow-out in Hawaii. This gives growers the earliest and most comprehensive information possible to make decisions for recertification on their farm, and to market their seed throughout the U.S.
Montana potato farms continue to use some old techniques that have withstood the test of time and continue to prove their worth as valuable tools in growing disease-free seed. This includes growing early-generation seed stock using hill uniting and tuber uniting. All tuber units and families are flagged individually and 100% tested for PVY. This allows for precise detection of disease and off-types in seed plots. The precise location of disease is documented, allowing for targeted rogueing. Another time-tested technique for growing disease-free seed is sanitation. Montana growers are fastidious about sanitizing all components of their planting, harvesting, storage and transport equipment to reduce the risk of spreading disease. Ring rot was a devastating disease that occurred sporadically up through the mid-1970s. Sanitation protocols, along with Montana’s rule eliminating seed potatoes from other states or countries entering the certification stream, have eliminated ring rot, and also provide a safeguard against other pathogens.
Current innovations in precision agriculture promise that the next 100 years will see advances in production that will enhance yields and, more importantly, the efficiency of crop production and inputs. Laboratory methods continue to improve, and pathogen detection methods will become even more important to assess the health status of seed potatoes. Robotic applications in laboratories will most likely have the same effect on the number of lab workers that it takes to process leaf and tuber samples that clod hoppers and vacuum separators have had on grading crews. Montana seed potato growers have set a high bar for quality seed potatoes in their first 100 years and will continue to embrace innovation to take them into the next 100 years.