Get in Touch
Back to Blog

When Varieties Migrate: How Climate Change Is Reshaping Potato and Onion Breeding in Europe

· Karevo GmbH

The potato and the onion — two of Europe's most important vegetables — are under pressure. Climate change is not only altering yields and growing regions, it is forcing farmers into a fundamental reassessment of their variety choices. What was taken for granted twenty years ago — Bintje in the field, Stuttgarter Riesen in storage — is increasingly being called into question.

But what exactly does this mean in practice? Which varieties are winning, which are losing? And why are Italian onions suddenly appearing in German fields? A stocktaking.

1. Why Variety Choice Matters More Than Ever

Potatoes and onions share one thing in common: they are both highly sensitive to climatic stress. As Goffart et al. (2022) document in their comprehensive analysis of the potato sector in north-western Europe, the optimal growing conditions for potatoes lie at average temperatures between 18 and 20 °C. When temperatures drop below 10 °C or rise above 30 °C, plant growth is severely inhibited. A good potato crop also requires 500 to 700 mm of water per growing season — a level that many European regions can no longer reach without supplemental irrigation.

The onion (Allium cepa L.) is equally water-dependent. According to Sansan et al. (2024), onions require between 350 and 550 mm of water during their growth cycle. The optimal temperature for leaf growth is between 15 and 20 °C, and for bulb development between 27 and 37 °C. But herein lies the problem: drought stress reduces plant height, decreases leaf area, inhibits photosynthesis, and leads to oxidative stress at the cellular level. The result is lower yields, irregular bulb formation, and compromised storability.

In north-western Europe — the traditional heartland of European potato cultivation — a clear trend has been evident for years: winters are becoming warmer and wetter, summers drier and hotter. According to Goffart et al. (2022), the frost-free period in Europe has already extended by two weeks in spring and two weeks in autumn since 1950. CO₂ levels have risen from 360 to over 600 ppm, which can boost photosynthesis rates by around 25 % — but this positive effect is largely cancelled out by heat stress and water scarcity.

2. Potato Varieties in Transition: Who Wins, Who Loses?

Germany, France, the Netherlands, Belgium, and Poland together account for around 60 % of total EU potato production. But within this core area, the balance of power is shifting dramatically.

The Fall of Bintje: From Undisputed Market Leader to Discontinued Variety

No other potato variety defined the twentieth century quite like Bintje. Bred in 1904 in the Netherlands by Frisian teacher Kornelis Lieuwes de Vries, Bintje dominated the European market for decades. In the 1960s and 1970s it accounted for over 60 % of Dutch growing area and was by far the most important variety in Belgium and France as well.

Today its star has fallen: in Belgium its share has shrunk to just a few per cent. The reason is its extreme susceptibility to late blight (Phytophthora infestans). In a climate with more frequent heatwaves and wetter winters, this disease weakness leaves no room for manoeuvre.

Fontane and Innovator: The New Industrial Potatoes

In Bintje's place come varieties that better meet the requirements of modern processing facilities:

Fontane (Agrico) is now the most important processing potato in Germany, with a market share of over 10 % among processing potatoes. This mid-early, floury variety stands out for its high starch content (22–23 %), excellent French-fry quality with good baking colour, and very high yields. Since 2019, Fontane has also been the most important variety in Flanders. Its success reflects the growth of the European French-fry industry.

Innovator, also of Dutch origin, has established itself as the favourite of fast-food chains. With long, oval, white tubers, a low sugar content (< 0.2 %) and an acrylamide reduction of around 30 %, Innovator precisely meets the requirements of major international buyers.

Spunta: The Heat-Tolerant Giant

Also noteworthy is the development of Spunta: this early-maturing variety, originally Dutch-bred (introduced 1968), holds the largest cultivated area on the European continent. Its decisive advantage: good heat tolerance combined with virus resistance and high yields. In a warming Europe, Spunta's importance could grow further — particularly as southern European growing regions approach their temperature limits and production shifts northward.

Belana: Germany's Number One Table Potato

Among table potatoes, Belana (Saatzucht Berding) leads with a market share of 5.1 %. This early-maturing, waxy variety wins with a creamy-buttery flavour, long dormancy (extended storability), and resistance to potato cyst nematodes of pathotypes Ro1 and Ro4. Its weakness: only moderate drought tolerance — a problem likely to become increasingly relevant in ever hotter summers.

Agria: The Versatile Processor

Agria, bred in Germany in 1985, remains one of the most important processing varieties across Europe. Deep-yellow flesh, high yields, and suitability for both French fries and crisps make it a favourite of the industry. As a predominantly floury variety, however, it is sensitive to water stress — during dry spells, significant yield losses are a real risk.

Polish Independence

Poland is home to one of Europe's largest potato gene banks, IHAR-PIB Bonin, with around 1,600 genotypes. The Polish breeding company Zamarte has maintained its own varieties for over 75 years, including Michalina, Gwiazda and Lawenda — early table potatoes with outstanding yields. This independence from western European breeding lines could prove an advantage under changing climatic conditions.

3. Onions: When the South Comes North

Global onion production in 2023 stood at around 4.6 million tonnes on approximately 213,934 hectares — making the onion the world's second most cultivated vegetable after the tomato. Asia dominates with 63.3 % of production, followed by Africa (18.1 %), the Americas (10.6 %), and Europe at 7.8 % (Sansan et al., 2024).

Within Europe, the Netherlands is the undisputed onion giant: over 1 million tonnes exported, a 20 % world market share, and more than 30,000 hectares under cultivation. Around 35 % of Dutch production comes from Zeeland, a further 40 % from the Flevopolder.

The Classic Storage Varieties

Commercial European cultivation has traditionally been dominated by long-day onions of northern origin:

  • Stuttgarter Riesen: The best-known German variety — robust, flat-round, mid-early ripening
  • Sturon: Selected from Stuttgarter Riesen in the Netherlands, ellipsoid, dark golden skin, storability up to 8 months, disease-resistant
  • Centurion F1: Modern F1 hybrid with very good yield and 6–8 months of storability
  • Hybound: Very early maturity, excellent skin quality, very slow sprouting

These varieties form the backbone of the European onion industry and are grown from Zeeland to Poland.

Darkstone F1: The Textbook Example of Climate Adaptation

Here things get interesting: the variety Darkstone F1 (Agri Saaten) strikingly illustrates how the variety landscape is changing under the influence of climate change.

Darkstone F1 is a mid-late Italian onion type with a bronze skin, high yield, and very uniform growth. Its special properties: heat resistance and excellent storability. Originally bred for southern European conditions, Darkstone F1 is increasingly being trialled and grown in Germany and central Europe.

Why is this remarkable? Traditionally, central Europe cultivated exclusively long-day onions of northern origin. The fact that a southern variety is now moving northward signals a fundamental shift. Darkstone F1's heat resistance makes it an attractive alternative in ever hotter summers — especially where traditional varieties suffer from heat stress — while it retains the long-term storability that is indispensable for commercial cultivation.

Source: Agri Saaten | LAKO Variety Trials Obersiebenbrunn 2023

The Polish Onion Family

Poland also maintains an independent onion breeding tradition. The Wolska variety, created in 1912, became the parent of seven further Wolska-type varieties (Czerniakowska, Warzawska, Sochaczewska, Kutnowska), differing in maturity, shape, colour, and storability. Wolska itself is a late-maturing variety with large spherical bulbs (90–160 g), 13.5 % dry matter, and very good storability. It was the main variety for Polish export for decades. Today, modern hybrid varieties such as Bonus F1, Medusa F1, and Bruce F1 round out the portfolio — all four store well into spring.

French and Italian Specialities

France recognises 56 registered onion varieties, including protected regional designations:

  • Oignon de Roscoff (AOP): Pink onion from Brittany, cultivated since 1647, AOC since 2009
  • Oignon doux des Cévennes (AOP): Sweet white onion grown on terraces in the Cévennes, AOC since 2003

Italy has around 100 onion varieties, including world-famous specialities:

  • Rossa di Tropea (IGP): Sweet red onion from Calabria with three maturity types
  • Borettana: Flat cipollini type (approx. 5 cm), ideal for caramelising

4. What Science Says About Drought Stress in Onions

The review article by Sansan et al. (2024) comprehensively summarises the current state of research on drought tolerance in onions. The findings are illuminating:

Morphological level: Drought reduces plant height, leaf length, leaf width, leaf area, bulb size, and overall yield.

Physiological level: Under water deficit, stomata close, CO₂ assimilation falls, the plant's water status deteriorates severely, and photosynthetic performance collapses.

Biochemical level: Reactive oxygen species (H₂O₂) accumulate, oxidative stress sets in, and antioxidants form (catalase CAT, ascorbate peroxidase APX, superoxide dismutase SOD). Simultaneously, plants produce osmolytes such as sugars, proline, betaine, and glycine as protective mechanisms.

Molecular level: At the DNA/RNA level, protein oxidation, lipid peroxidation, and changes in genetic material are observed.

Authors' conclusion: To secure onion production under future climatic conditions, three strategies must be pursued simultaneously: (1) breeding drought-tolerant varieties, (2) improved irrigation methods, and (3) tapping genetic resources from wild species and local landraces. The authors also emphasise that 99 % or 95 % of all known onion varieties worldwide are conserved in gene banks — an important foundation for future breeding.

5. Forecast: Where Is the Journey Heading?

Based on the available data, the following trends can be projected for the coming years:

Variety Type Trend Driver
Fontane Potato Strongly rising French-fry growth, high starch
Innovator Potato Rising Fast-food demand
Spunta Potato Rising Heat tolerance, climate resilience
Bintje Potato Strongly falling Phytophthora, no resistances
Belana Potato At risk Moderate drought tolerance
Agria Potato Stable/falling Heat sensitivity (floury)
Darkstone F1 Onion Strongly rising Heat resistance, storability
Sturon / Centurion Onion Stable Proven storage varieties
Stuttgarter Riesen Onion Slightly falling No specific climate adaptation

Central factor: Breeding new varieties takes 15–20 years. By the time a new, climate-adapted variety reaches the market, conditions will have changed further still. This explains why existing varieties with favourable traits — such as Spunta's heat tolerance or Darkstone's combination of heat resistance and storability — are suddenly gaining in value. They are, as it were, "accidentally" well prepared for the new conditions.

6. What Does This Mean for Sorting?

As the variety landscape shifts, so do the requirements for optical sorting. New varieties often bring new colour nuances, shape variants, or surface structures. Darkstone's bronze skin, for instance, differs markedly from the classic golden-yellow long-day onions. Fontane's oval, elongated tubers require different sorting parameters than the rounder Bintje potatoes.

This is precisely where modern opto-electronic sorting technology comes in: systems that are not rigidly calibrated to a single variety, but can flexibly map different sorting criteria. The more diverse the varieties on the market, the more important becomes the ability to precisely detect and classify different characteristics — from skin colour and shape through to defects.

References