Building Resilience and Flexibility into Midwest Organic Potato Production: Participatory Breeding and Seed Potato Production

Building Resilience and Flexibility into Midwest Organic Potato Production: Participatory Breeding and Seed Potato Production

Summary

Organic farmers in the North Central Region face a regional shortage of organically produced seed potatoes, limited availability of desired specialty varieties, and limited information on variety performance under organic management. Very little potato breeding and selection focuses on the needs of organic farmers. A decentralized system of seed potato production and breeding by a network of organic farmers would meet regional seed potato demands, enable farmers to evaluate and select outstanding lines from crosses between existing varieties, and promote interaction and learning among farmer peers. This project brings together researchers and farmers to develop goals for breeding and seed production, to trial seed potato production and breeding on organic farms, and to assess economic impacts of on-farm seed potato production.

Objectives/Performance Targets

Objective 1: Evaluate the practical and economic feasibility of on-farm production of high quality seed potatoes from minitubers and foundation class seed potatoes.

Many pathogens that may infect potato plants can be carried in the daughter tubers and will impact the productivity of the next crop. Commercial seed potato production begins with plants propagated in sterile tissue culture, which are then grown in protected greenhouse environments to produce small disease free “minitubers”. These minitubers are then used for field production. This objective has been modified to include on-farm production of seed potatoes from foundation seed stock, the grade of seed potatoes planted by certified seed potato growers, since multi-year trials have shown low yields from minitubers in field-grown organic potatoes. Potential exists for hoophouse and other small scale organic production from minitubers. Saved tubers from on-farm seed production trials will be compared to purchased organic seed potatoes for crop health and yield. The effect on farm income of on-farm seed potato production versus purchase will be determined using partial budgets.

Objective 2: Provide training, coordination and resources for a farmer-participatory potato breeding network.

Farmers will be provided with true potato seed from crosses between varieties that performed well on organic farms in our previous trials, and trained to make their own crosses as desired. We will collaboratively generate selection guidelines for on-farm breeding line trials to address breeding goals. Tubers from selected breeding lines will be saved and replanted for comparison with standard varieties. Promising lines will be introduced into tissue culture for long term maintenance and production.

Accomplishments/Milestones

Objective 1: Evaluate the practical and economic feasibility of on-farm production of high quality seed potatoes from minitubers and/or foundation seed potatoes.

Of the three participants who planted minitubers in 2015, two replanted seed potatoes saved from 2015 minituber crops. Zach Paige at White Earth Land Recovery Project replanted saved tubers for Red La Soda and French Fingerling, with 30 plants for each variety. Kat Becker at Stoney Acres Farm replanted saved tubers for Carola, French Fingerling, Red La Soda, and Yukon Gold, with two rows of 10 plants for each variety. Certified seed potatoes for varieties Red La Soda and Carola were grown as comparisons. Observations from White Earth indicate comparable yields for Red La Soda from saved and certified seed sources. No comparison to certified seed was made for French Fingerling, but the usable yield was comparable to other varieties grown at White Earth (see below). However, almost half the yield from the saved French Fingerling tubers was unusable. Most of the discarded French Fingerling tubers had high levels of common scab, a tuber defect caused by the soil bacterium Streptomyces scabies.

Table 1: Yields from seed potatoes saved from minituber trials at White Earth and Stoney Acres Farm

In addition to saved seed potatoes from minituber crops, Zach Paige at White Earth LRP replanted saved seed for four  other varieties that had been part of a 2015 potato variety trial. Although the seed potatoes planted in this 2015 trial were not certified seed potatoes, they were produced from disease-free minituber stock on organic land at the West Madison Agricultural Research Station in Wisconsin, and the crop was closely inspected for evidence of disease.

Table 2: Yields from seed potatoes saved from potato variety trial at White Earth

Eleven participants trialed seed potato production from foundation seed potato stock. Foundation seed potatoes for varieties Langlade, Adirondack Red, Carola, Teton Russet, French Fingerling and Freedom Russet were obtained from the Lelah Starks State Seed Potato Farm. Each farm trialed between 1 and 4 varieties in small plots within their regular potato fields. Tuber samples were collected at harvest, and are currently being sprouted in greenhouse conditions to assess incidence of Potato Virus Y (PVY), the most common potato virus affecting seed potato certification. PVY incidence will be communicated to growers, who may choose to replant saved tubers with low or zero incidence. At least four growers have committed to replanting saved tubers in comparison to certified seed potatoes, assuming their saved tubers have low PVY incidence.

Objective 2: Provide training, coordination and resources for a farmer-participatory potato breeding network.

Seven participating growers trialed mixed progeny populations from crosses for productivity and marketability, as a test of the feasibility of using true potato seed (TPS) as the basis for a production system. Since potatoes do not breed true, potatoes derived from TPS are less uniform than those from standard clonal propagation of varieties, and are likely to be more suited to direct markets such as CSA farms, which anecdotally report more acceptance of unusual produce. These populations, derived from crosses between parental lines that had previously performed well under organic management, were grown in the 2015 organic seed potato production field at West Madison Agricultural Research Station, and total yields from these populations were comparable to yields from minitubers of standard and heirloom varieties in the same plot. Breeding populations were derived from crossing of Adirondack Blue and Fenton Blue (AxF series), Sweet Yellow Dumpling and Adirondack Blue (SxA series), White Lady (a Potato Virus Y resistant variety) and Adirondack Blue (WxA series) and Yellow Rose and Adirondack Blue (YxA series). Growers were asked to answer the following questions: would they want to grow these populations again; what were the strongest and weakest points; and to rate the marketability and eating quality (1-5 scale with 5=best).

Table 3: Grower evaluations of mixed progeny populations from potato crosses Adirondack Blue and Fenton Blue (AxF series), Sweet Yellow Dumpling and Adirondack Blue (SxA series), White Lady and Adirondack Blue (WxA series) and Yellow Rose and Adirondack Blue (YxA series).

In 2015, breeding lines were selected from mixed progeny populations for the crosses described above, plus selfing of Adirondack Blue (AxA series), crosses of Eva (a Potato Virus Y resistant variety) with breeding line 118, and crosses of Keuka Gold with Yukon Gold (KKGxYKG). Breeding lines were planted in plots of 5-10 plants (depending on availability of seed potatoes) in the West Madison Agricultural Research Station organic field. Two parental varieties were also planted – Fenton Blue (FEN) and Sweet Yellow Dumpling (SYD) – as well as a widely adapted check variety, Red La Soda (RLS); these varieties were planted in replicated plots whereas single plots were planted for the breeding lines. As shown in Figure 1, several lines had marketable yields substantially above the parental lines. Due to a late blight outbreak in September, tubers from these lines will not be distributed to growers for trials in 2017, but healthy tubers have been selected for introduction into tissue culture, and these lines should be available by 2018 for minituber production, enabling field trials in 2019.

Minitubers for 14 breeding populations were planted in the organic seed potato production field at West Madison ARS. Seven of these populations derived from crosses between Potato Virus Y-resistant lines (PVY^R; resistance derived from Eva, Tacna, or White Lady) and popular varieties including Carola, Adirondack Blue, Red La Soda, and Spartan Splash.  The other seven populations were open-pollinated populations from female parents Aylesbury Gold (PVY^R), Barbara (PVY^R), Picasso (PVY^R), Early Bangor, Makah, Purple Pelisse, and Red Thumb. The seed field is not set up as a yield trial, but total yield data was collected for each population and averaged 0.85 lb/plant, ranging from 0.3 to 1.9 lb/plant. Although late blight incidence in nearby plots rules out distributing and testing these populations in 2017, select tubers were collected for introduction into tissue culture and later minituber production and field evaluation.

At White Earth, Zach Paige has selected five lines from true potato seed-derived plants grown in 2015, from crosses among yellow varieties Carola (CAR), Keuka Gold (KKG), Yukon Gold (YKG) and red varieties Dark Red Norland (DRN) and Chieftain (CFT). Yields are shown in Table 4. Zach reports that eating quality of these lines is comparable to named varieties that he grew at his location.

Table 4: Yields from selected clonal lines at White Earth Land Recovery Project.

Impacts and Contributions/Outcomes

Updates on research progress in organic seed potato production and organic breeding were presented at fall field days at the West Madison and Spooner Agricultural Research Stations, respectively attended by approximately 60 and 30 farmers, county extension agents, plant breeders and seed company representatives. We discussed seed potato production and breeding objectives during visits to Whitewater Gardens Farm, Dream of Wild Health, the Mille Lacs Indian Reservation, Hungry Turtle Farm, Lac Courte Oreilles Ojibwa Community College Farm, the Bad River Indian Reservation, Keppers Pottery and Produce, Maple Ridge CSA, Stoney Acres Farm, and with grower groups from the Superior, WI, area.

There were many opportunities this winter to engage with organic farmers and other researchers in discussions about organic potato breeding and seed production. At both the Organic Vegetable Production Conference (Madison, WI) and the MOSES Organic Conference (La Crosse, WI), we discussed priorities in organic potato breeding in a roundtable format with vegetable growers. At the Indigenous Farming Conference organized by the White Earth Land Recovery Project, I met with growers interested in seed potato production and breeding, many of whom farm or garden as part of food sovereignty initiatives on their reservations. I also participated in a seed swap event, using this event to distribute true potato seeds and discuss potato breeding and selection approaches. It was encouraging at this event to reconnect with two farmers who had obtained true potato seeds from me in the previous year, and had successfully grown and selected appealing potato lines.

Through these events, I connected with three more organic farmers interested in seed potato production, two located in Wisconsin and one located in North Dakota. One of the Wisconsin growers is interested in greenhouse production of early generation seed potatoes from minitubers, an essential link between pathogen-free tissue culture collections and organic field production, and we are planning a pilot trial for the summer. I am discussing the potential for organic seed potato trials of several varieties with the other two growers.

Collaborators: