Want to brighten up a salad with a fresh flavor? Add crunchy radish. The contrast between its red skin and white flesh also adds a pop of color to that summer dish. But, not everyone is a fan: for some, radishes taste too sharp. That calls for input from breeders who are busy developing milder varieties. And white, purple, and striped radishes? Yes, there is something for everyone.
Radish, a member of the cruciferous family (cauliflower, broccoli, Brussels sprouts, etc.), originated in Asia. It has been found in European vegetable gardens as far back as Roman times. Besides the well-known round, red radish, scientific name, Raphanus Sativus var. Sativus, the genus includes the larger, milder daikon and black radish.
Red radish is more popular in the West, so breeder Hazera focuses on this species to boost the slowly increasing consumption with a wider range of flavors and colors. Its indoor and outdoor cultivation radish program has been one of the most important spearheads in this Dutch company's R&D programs for more than 40 years. The breeding program also considers the challenges growers face. In this article, global product manager Adam Prabucki and sales manager Dirk-Jan Polak delve into that.
Youngsters are getting involved
"The global radish market's annual growth is slow but steady, "begins Adam. "Red radishes make up almost 99% of the supply, but it's the colorful varieties that seem to be sparking interest as exotic products. It used to be the older generation that ate radishes; now, it looks like young people are being drawn to them too. One of our breeders recently told us he dreams that eventually, radishes will become the healthy snack of choice."
Adam says radish is not only tasty and fresh but also very healthy. "A hundred grams provides 25% of your daily Vitamin C requirement. Healthy snacks are generally gaining increasing attention, and radish can piggyback on that trend," he explains. Dirk-Jan agrees, adding that while bushel sales are stagnating, loose radishes sales as an on-the-go product are rising. "You can combine those with other products, like baby carrots. Our sister company, Vilmorin, has developed a very sweet variety, which was recently voted the tastiest snack carrot of the year. You can find 200g bags of those and our radishes on store shelves already," he says.
The goal: a choice between mild and sharp
Dirk-Jan notes that when it comes to radishes, consumers are divided between those who love its sharp taste and those who, because of that, avoid them. "But we can undoubtedly use milder varieties - and a color trigger - to convince the latter. Radishes can often dominate a salad with its flavor; not everyone likes that. We have a long-term goal of perhaps breeding milder varieties, so consumers can ultimately consciously choose between sharp and mild."
That flavor, though, is not entirely variety-dependent. Growers and weather conditions also affect that. Until now, radishes' mustard oil content predominantly determined its flavor. The sunnier, the more of that oil the radish produces. "Radishes are generally less sharp in winter than in warmer months. But this summer, with Zonella F1, we're introducing a variety that, for the first time, bucks that trend," Adam announces. Zonella F1 stays nice and white on the inside, growing to a shorter length than the existing standard.
Hazera's top European markets for its hybrid varieties are the Netherlands and Italy for greenhouse cultivation and Germany, Poland, and the United Kingdom for outdoor cultivation. Outside of Europe, the focus is on the US. "There are an unusually large number of greenhouse projects in many parts of the world, so the share of hybrid varieties is increasing. That's good for higher average yields, a more uniform product, and better internal quality," says the product manager.
Extreme weather tolerance
Adam finds several characteristics determine a variety's success. Along with those already mentioned - yield, uniformity, and internal quality - he mentions good skin quality - "the color shouldn't fade after washing" – and tolerance to cracking in the field.
That tolerance is closely related to the ever-increasing frequency of extreme weather. "Extreme weather conditions mean more than merely hot or wet. It could be a heat wave that suddenly turns into persistent rain that floods fields. We're thus looking for tolerances for drought, heat, and wet conditions. Climate change is also why protected cultivation, including radishes, is on the rise, from Kazakhstan to Europe to Canada. You can easily grow radishes year-round in controlled conditions, even in vertical farms with sophisticated light recipes and at a constant 18°C. Here too, there's a role for plant breeders; this type of cultivation requires specially adapted varieties," Adam continues.
In Europe, energy costs, especially gas, play a major role in greenhouse cultivation. As does social pressure to keep CO2 emissions as low as possible. The demand for winter varieties that have the same yields and quality traits at slightly colder temperatures is, therefore, on the rise. "We had to look for vigorous varieties with strong foliage. But we couldn't go overboard because 50 cm-high leaves make mechanical harvesting impossible."
Mechanical harvesting
Breeders have to constantly balance one requirement and another. "In the Netherlands, most radish acreage is harvested by machine, both for efficiency and to escape rising labor costs. In breeding, the focus should be on varieties with straight, not-too-long, but also not-too-short leaves. That's because the machine uses those leaves to pull the radish from the ground. Especially in the Dutch winter, those leaves can have difficulty developing sufficiently. In the summer, the reverse threatens to occur: the foliage grows too quickly and strongly. Growers look to the breeding sector for answers to those challenges," Adam points out.
Breeders also include the sustainability aspect in their programs. "Not long ago, a vital active component for seed treatment's registration was withdrawn. So, for several years now, we've been doing trials with third parties on an organic application, with already promising results. But its registration goes through the same process as crop protection products, so its commercial rollout will take a while."
Varietal innovation instead of chemicals
Regarding crop protection in general, legislation, particularly in the EU, is restrictive, while diseases and pests are becoming increasingly common. And where chemicals are no longer the solution, varietal innovation quickly comes into the picture. "Pathogens are, of course, timeless, though," Adam remarks. "Some 30 years ago, we introduced the first Fusarium-resistant radish for Dutch greenhouse horticulture: Favorella."
"For outdoor cultivation, we developed a variety resistant to downy mildew, and we helped growers in the American Midwest with a variety unaffected by Rhizoctonia outbreaks. The next big challenge, especially in Europe, is white rust water mold. But remember: you can't pull solutions out of thin air. It takes 18 to 20 years to develop a new radish variety. That's going to keep me busy until I retire," Adam concludes, laughing.
This article was previously published in Primeur May 2025. Click here for the link to the entire edition
For more information
Hazera
Dirk-Jan Polak
www.hazera.nl
[email protected]