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Stories - 11-10-2022

Contributing to the world food supply through research into plant health

Joke Klap works on the development of resilient and robust vegetable varieties. That’s how she’s contributing to plant health and food production. She explains how Rijk Zwaan is contributing to plant health by developing vegetable varieties with resistances.


“For me, ‘healthy’ plants are resilient and robust plants that can cope well with the stress factors in their growing environment. Such factors can include aridity, soil salinisation and high temperatures, which are known as abiotic stress factors, but also biotic stress factors such as viruses, fungi, bacteria, nematodes and insects that cause diseases and plagues,” says Joke. As a team leader in Rijk Zwaan’s phytopathology department, her work is focused on the development of resilient and robust vegetable varieties. 

Food losses

“In developing countries, plant diseases and pests are often a major cause of food losses; complete harvests can fail, and no harvest means no food. That’s why plants that are resilient and resistant against diseases are very important.”

In the Netherlands, Spain and France, Rijk Zwaan has Phytopathology departments where the disease resistance of vegetable varieties is assessed in specially designed test facilities. In Turkey, Australia and India, the disease resistances are tested under local conditions. That’s for a reason: “Different countries and climate zones have different disease pressure, climatological conditions, soil quality and other environmental factors that affect a plant’s resilience.”


What is the key to making a plant resistant against a disease or pest? "That’s the question that we’re continuously trying to answer through phytopathology and breeding. To do so, we often study the genetic traits of plants that thrive in certain regions. Is it just one gene or a combination of various parts of the genome that makes the plant resilient? Breeding crosses in the resistance as precisely as possible. In the Phytopathology department, we let the disease or pest loose on all the test plants. In the plants that remain healthy, we can conclude that the resistance has been crossed in successfully. Multi-gene resistance is usually the strongest sort of resistance, but it’s also the most challenging to find and cross in.”

Resistances more important than ever

“There is a growing demand for resistant varieties due to climate change, increasingly extreme weather conditions and the rise in international travel which helps diseases and plagues to spread more rapidly. Besides that, there has been a sustained reduction in the use of crop protection agents over the years, so resistant plants are much needed around the world,” continues Joke. Fusarium-resistant cucumbers are one good example. “And it doesn’t matter how good our lettuce or spinach varieties are, for instance; if we don’t offer the right resistances against downy mildew, no grower will want them.”

Besides crossing in resistances, Rijk Zwaan also breeds varieties that allow natural predators such as insects to do their job better. The new ‘hairless’ aubergine varieties with CleanLeaf® are a good example. These varieties have very few trichomes (hairs) on their leaves, making them less attractive to whitefly and thrips. Moreover, due to the low disease pressure, the use of predators such as mites is even more effective, thus reducing the need for growers to use crop protection agents. 

Research into our food

“Plants form the basis of our food chain, which is why I’m glad that the FAO has got plant health so high on the agenda. It’s important that we continue to conduct sufficient research in order to keep developing resilient and robust vegetable varieties,” she states.

Sharing a healthy future