“Storage capacity of sweet potatoes in Europe challenge for year round supply”
In more and more European countries the sweet potato is discovered by growers. Production is increasing. Yet Patrick FitzGerald, of plant tissue culture labs and nursery Beotanics, is focused on development of safe the future of the production. He has multiple worries, on the one hand, there should be more attention for the varieties, because they require a delicate touch. On the other hand, he’s worried that unwanted diseases hitch a ride with the import of plant material, which can reduce the yield, and thirdly, he says infrastructure for good storage is lacking.
Patrick FitzGerald on a field in Portugal (left). Orleans sweet potatoes (right).
The growing production brings risks with it. “If growers become too complacent with the variety success in good years, they may delay the harvest too late to get higher yield and suffer losses in poor harvest conditions. If soil temperature is going below 10 – 15C for long periods it has a negative effect,” Patrick says. Although yield can still be good then, such temperature mostly has an effect on storage quality. Storage is an evolving challenge for the European sector in any case. “Storage capacity is a barrier to effective and profitioble produciton,” Patrick says. That’s not due to the available varieties, but to infrastructure in Europe.
Sweet potato not a potato
The storage starts with a phase in which the sweet potatoes are cured at 28 degrees Celsius and 85 per cent atmospheric humidity, after which temperature has to be brought back down to about 14 degrees and 85% humidity. “That’s a critical stage for storage later in the season,” he warns. “Growers shouldn’t jump on this trend to hastily, that would result in problems.” Patrick has noticed potato growers throwing themselves at sweet potatoes. He mentions potatoes and sweet potatoes are two completely different organisms, and require different approaches. “Sweet potatoes require different circumstances than potatoes. Knowledge is an important factor, that can be seen in the US as well. Growers thinking they’re dealing with a potato, are headed for disaster. It’s a completely different product.”
Tissueculture plants of sweet potato.
Irish company Beotanics has been working together with its Joint Venture partner Nativa in Portugal on improving sweet potatoes since 2005. Focus was more on hobby growers back then. A few years later, an agreement with the Louisiana State University was agreed upon, to have the varieties bred there tested for the European market. “We soon found out Ireland wasn’t the best place to test the varieties,” Patrick says with some light self-mockery. Between 2009 and 2010, tests were done in Germany, France and Portugal. “In 2010, we learned the tests in France went very positively,” Patrick explains. “As of 2013, French growers know sweet potatoes are a good product.”
Sweet potato varieties Evangeline (right) and Orleans (left).
Varieties for different types of soil
The French production doesn’t focus on large volumes, and still functions as a by-product for the growers. Areas are between 0.5 and 3 hectares. “Rumours have been spreading like wildfire since then.” FitzGerald Nurseries a Beotanics company is the owner of the European license for varieties Evangeline, Orleans, Bonita, Murasaki and Burgundy that is sublicensed To Nativa in Portugal where planting “slips” are produced for the European the farming industry. Burgundy is mostly meant for chefs. “We commercially marketed these varieties in Germany, Sweden, Norway, Switzerland and other countries in Europe,” Patrick continues. “We’ve seen good results in various countries.” In the north of Europe, Orleans is most popular variety.
Tissue culture plants 3 weeks out of lab ready for planting (right).
“We’ve been testing these varieties for more than ten years, and we’re now marketing them. We’re trying to grow gradually. But we see that our varieties aren’t as appreciated as they should be.” Dependent on production circumstances, other varieties are needed, that’s why Patrick thinks it’s necessary to announce it if a variety is reported a success. “We’ve personally seen that not every variety is suitable for every type of soil, even a good variety, and not all of our varieties will be successful, for example one variety, in sandy soils another in heavy soils. Besides, some varieties are resistant and have different storage characteristics. That’s why it’s important to communicate about the varieties.”
Plant beds establishing in Portugal (left). Red skin white flesh, an Asian typespecial variety Murasaki (right).
Contaminated plant material
“Our varieties are resistant against specific diseases and pests of sweet potatoes, we ensure they are virus clean, which can be a serious threat to the yield.” Some viruses result in a harvest that’s 40 per cent smaller. In the US in particular this is something growers are contending with for many years. “We have a laboratory in Ireland in which we follow American guidelines for plant health, which means we specifically test for sweet potato viruses. The contamination in plant material is one of the biggest challenges in European production and a lot more needs to be done to protect crop health.”
Mother plants in Ireland ready to ship to Portugal.
However, Patrick’s biggest worry is that contaminated plant material is imported or spread around Europe due to increasing interest in this production, so that diseases and viruses that influence harvests in the Americas and Africa, for example, also start affecting harvests in Europe. He emphasises that Beotanics in Ireland and Nativa in Portugal works with various protocols to prevent contaminated material from spreading. From Ireland, the plant material is shipped to other markets, including Africa and Egypt. Through joint venture Nativa in Portugal, the plant material for European production is traded.
Opportunities for Northern Europe
The early adapters of sweet potato production in the north of Europe are France and Germany. Production developed in France is quicker because the French partner of Beotanics Graines Voltz put much energy in it, and supplied plants to growers that can be harvested after 115 days and have a high yield. “The Netherlands and Belgium are next, and then Sweden and Norway. We’ve heard positive stories about the production near Oslo,” Patrick says. “But the growers in the north have to be careful, there’s always a chance for a bad harvest.”
Patrick sees opportunities for the production in Northern Europe, because of the rise in local product in particular. Besides, he has seen other opportunities to be distinctive on the market. However, these are not on the market on which large volumes are produced. The majority of the production can be found in the south of Europe: Portugal, Spain, France and Greece.
Baby food and animal feed
“Sweet potatoes have been grown in Europe for hundreds of years, but not properly.” In the 17th and 18th century, sweet potatoes with white flesh and red skin was much grown. However, Beotanics' white variety Murasaki had to be promoted. “We received kick back because the sweet potato wasn’t orange but this is changing,” Patrick says. According to him, the biggest risk for the production is if everyone enters the market at the same time. “The problem is not so much the volume, there is room for imports and home production in a healthy growing market, but the fact that there’s too much supply in September,October and November, because there’s not enough storage capacity.”
Finally, Patrick mentions there’s a market for sweet potatoes. “There’s demand for year-round sweet potatoes. Demand from industry is also increasing, for baby food, for example, crisps in meals and even animal feed.”
For more information:
Beotanics - FitzGerald Nurseries
Tel: +353 (0)56 7728418
Fax:+353 (0)56 7728481
Publication date: 11/28/2017
Author: Rudolf Mulderij
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