Small potato production is expanding in Saskatchewan to meet increased market demand for “creamer” potatoes with a target size of 20 mm to 40 mm in diameter. Specialty potato companies, such as The Little Potato Company of Edmonton, have found new culinary markets for so-called “little” potatoes. Now growers in Saskatchewan are taking notice, particularly in the irrigated region of Outlook.
However, small potato production is markedly different from conventional potato production and has a unique set of requirements, including suitable varieties, special equipment and agronomic practices that differ from large potato production in several key ways.
According to Jazeem Wahab, horticultural crops agronomist at Agriculture and Agri-Food Canada’s (AAFC) Saskatoon Research Centre, small potatoes are emerging as a higher-value option for the producer and another culinary choice for the consumer. However, growing small potatoes presents challenges to growers. “We have to develop cost-effective agronomic production practices that can produce the size and grade of small potatoes the market demands,” Wahab says.
Since 2006, Wahab has headed up a long-term study analyzing the effects of seed tuber size, seed spacing and harvest timing on growth and yield of small potatoes in Saskatchewan. He says many factors influence production of high-quality small potatoes, including weather, irrigation, harvest timing and variety. “Not one factor operates independently – we have to take a holistic approach,” he says.
The project received support from Saskatchewan’s Agriculture Development Fund from 2007 to 2009, as well as some funding from The Little Potato Company. Wahab hopes to continue the study this year with AAFC funding.
According to Saskatchewan’s Ministry of Agriculture, the project was initially aimed at “finding the best small potato germplasm and developing cost-effective and cultivar-specific agronomic practices for producing small potatoes,” as well as determining the potential for producing small potatoes from commercial table potato cultivars.
Studies under the project’s umbrella included the screening of creamer clones developed by AAFC potato breeders and identifying commercial potato cultivars suited for small potato production.
The project aims to benefit Saskatchewan’s potato industry by bringing greater revenue to the province’s producers through the higher-value small potatoes, which also increase the accessibility of lucrative urban markets. Small potato production is also more cost-effective, as small potatoes are harvested earlier than conventional large potatoes, and thus require fewer inputs such as pesticides.
Wahab and his team of researchers analyzed the impact of seed tuber size, seed spacing, harvest and top kill timing under irrigated conditions on three proprietary small potato varieties – Baby Boomer, Piccolo and Blushing Belle – as well as a few commercial and table standard large potato varieties, including AC Peregrine and Norland.
Larger tuber seeds for bigger yields
In one study, six seed tuber sizes were used in the study’s treatments, ranging in size from as small as 20 mm to as large as 50 mm in diameter. “In general, we found the larger the seed tuber, the bigger the yields,” Wahab says. Larger seed tubers also tended to decrease tuber size.
Two seed spacings were studied: 15 cm and 20 cm, respectively, between seed piece plantings. In general terms, closer spacings resulted in higher marketable yields, although Wahab says more data is needed. “I’ll be working on consolidating data from the years of the study to come up with recommendations,” he says. “What I can say is that some years, closer spacing yielded significantly higher, and some years it did not. The year that it did not respond well, it was very hot – weather can have a significant impact.”
In another study focused on harvest timing, one top-kill stage was used in the first year, based on tuber development of the different cultivars. Three top-kill stages were used in the second year, at 10, 11 and 12 weeks after planting.
Wahab says harvest timing depends on variables such as weather, but harvesting after 10 weeks usually results in a reasonably good small potato yield. “A nine-week harvest results in very low yields, a 10-week harvest in fairly good yields. At 11 weeks you get some larger potatoes, depending on the variety,” he says.
The team also studied the effects of harvest timing on some standard commercial varieties, such as Norland and AC Peregrine red potato varieties. What they discovered was AC Peregrine could also be grown for the small potato market if harvested early. But even though such adaptability would seem to make varieties like AC Peregrine attractive for commercial growers hoping to break into the small potato market, Wahab says most growers cannot afford to grow potatoes for both markets, as small potato production requires specialized equipment.
Before small potato production can grow into a major player in Canada’s potato industry, more suitable varieties will be needed, Wahab says. “The traditional varieties that are grown on a commercial scale have been bred to grow large. The number one thing we need is the best varieties for this particular purpose.”
Wahab believes small potatoes have a bright future in Canada, even though small potato production is still considered “niche.”
Michele Konschuh and her team were able to produce four crops of seed potatoes, each one more successful than the last. Photo by Michele Konschuh/Crop Diversification Centre.
Mystery surrounds animals, people or things that appear out of thin air and movies scare us with a villain appearing out of the mist. But there are some very positive and non-threatening aspects to using thin air and mist in potato production. With the support of Alberta potato growers, Michele Konschuh may have fine-tuned a better, more efficient, financially viable means to produce seed potatoes.
Konschuh, a potato research scientist with the Crop Diversification Centre in Brooks, Alta., has used aeroponic technology to produce seed potatoes in a chamber that only requires the roots of the plants to be misted regularly. The PIP 200 Potato Incubator was shipped to Canada from NorthBright Technologies in Chicago. The company had previously developed a prototype called the PIP 100, but having heard about the system, seed growers in Alberta were keen to try the technology. The PIP 200’s arrival posed some challenges.
“We had to put the equipment together when it arrived,” Konschuh says, because there were no precise instructions for something that was still in development. Then, she and her team had to figure out how the equipment worked. “The first crop was humbling and we planted it in winter, which was not the best scenario, because we struggled to get the roots developed.”
The aeroponic system includes three chambers stacked on top of each other. The top chamber is open to the greenhouse and the tops of the plants grow upward into carbon dioxide and sunlight. The middle chamber hosts a plug that holds the tissue cultured plantlet. On the bottom is a fabric layer the roots push through into a dark, open area that is misted to feed the plants and keep them alive. The learning curve was not smooth, but jagged, as the team had to learn how to set up the chambers. The fabric the roots needed to push through was inadvertently substituted for something too heavy. Preventive maintenance procedures were learned through trial and error. Watering issues also became a challenge because, like any field situation, too much or too little stresses plants, causing yield and quality issues.
“We don’t know much about growing potatoes ‘in captivity,’” Konschuh says. But, faced with a tight schedule, she and her team were able to produce four crops of seed potatoes and each one was more successful than the one before.
“The potato growers did not expect this to be a long-term project, it was merely designed to assess a potential commercial unit,” Konschuh says. “We learned more each time we grew a crop, but we didn’t solve fertility issues and we need to understand root systems better.”
The provincial government recently purchased the PIP 200 and, on recommendations by Konschuh, the manufacturer is making adjustments to create the PIP 150 that will be more “user friendly.” She says the assessment did remove some of the risk that commercial seed potato growers would face if they decide to use the equipment themselves. In the four crop trials, she learned the system does work and that it can be economically viable.
After the first couple “less than stellar” crops using the equipment, the researchers learned and improved, hitting a high of 15 to 20 marketable seed tubers per plant. But, Konschuh admits, in the last trial only one variety was grown. In the first round, 14 varieties were grown and, she explains, each variety had its own idiosyncrasies, making it difficult to manage the fertility and water requirements to ensure each crop was managed successfully.
“We increased yield 10 times over what can be done in a greenhouse using traditional production methods,” Konschuh says. “We used less nutrition and water to produce the seed as well. The cost of producing seed potatoes was reduced based on lowering our variable cost per tuber. I think, realistically, a seed grower using this system could pay it off in about five years.”
The cost of production, according to the researcher, was 35 cents per tuber compared to the usual 75 cents accrued by the average grower. The team was able to grow some of their production in a field with no apparent differences when compared with traditionally grown seed. However, Konschuh suggests, the cost of seed will most likely not be lowered, but the availability of seed would ensure the province’s seed potato supply.
While the future of seed production in an aeroponic system appears very positive, there is still much to learn and Konschuh admits that it is a less forgiving system than hydroponics. “With aeroponics, you only have about three hours to save the crop if your water pump quits,” she says. “You also need good light and we need to understand fertility and manage plant density better.”
Even though Konschuh no longer works directly with the PIP 200, she sees many possibilities to use it as a research tool to study how tubers develop in the field, to understand how root systems feed plants, and to learn how to better control diseases.
Finally, the assessment of the PIP 200 is offering seed growers a new option and, with proof the system is viable and cost-effective, the future of seed production in Alberta could be changed. Konschuh believes what she was able to accomplish in only four crops is giving growers enough information to make informed choices about whether to take the leap and purchase the equipment. In the near future, producers may be growing tubers out of thin air in a misty environment and that’s not the least bit scary.
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