Some crop varieties are less susceptibel to to disease than others. This is called natural resilience. Usually the difference is due to defence compounds in the plant: these compounds appear to be the ultimate weapon against powdery mildew, for example. The Greenhouse Horticulture and Flower Bulbs Business Unit of Wageningen University & Research is investigating whether these compounds – and, therefore, the resilience of the crop - can be identified and measured, and perhaps even stimulated during cultivation.
There are, generally speaking, two mechanisms of natural resilience. First by morphological adjustments. In that case, for example, a variety has a thicker lmaking it more difficult for t some diseases and pests to attack. The other mechanism is through chemical modifications, such as higher production of secondary metabolites asplant defence compounds which make it difficult for attackers.
Resilience is measurable
But which compounds work against which pest or disease? To answer that question, plant material from a number of gerbera and rose growers was examined. Susceptibility of each variety to powdery mildew was known. Plant compounds were identified and measured using a metabolomics method In this way the material can be compared and looked for differences in plant compounds. The method works. In other words: resilience to powdery mildew can be measured.
This knowledge can be used forthe breeding of new varieties: breeders now know what to look for in research for new varieties and breeding. In addition, WUR is investigating whether it is possible to stimulate the plant compounds through cultivation measures, so that a susceptible variety becomes less susceptible. And perhaps one day natural crop protection can be developed with this method.
WUR also investigated morphological adaptations against powdery mildew in these crops. It turns out that a thick wax layer in rose not only protects againstdessication, but also against mildew. WUR is also investigating whether it is possible to strengthen the wax layer by means of cultivation measures.
The research into natural resilience to mildew is a PPP with the participating parties LTO Glaskracht Nederland, Stichting Programmafonds Glastuinbouw / Stichting Kijk, Gewascoöperatie Roos, Gewascoöperatie Gerbera and Coöperatie Royal FloraHolland.