Growing crops in sets of two or more wild potato species with resistant genes, combined with simultaneous introduction of resistance management, can ensure that these plants remain resistant, in the long term, to aggressive diseases.
This combination offers worldwide opportunities for making agriculture more sustainable, for instance as part of integrative pest management, in which (low dose) chemicals are only used on rare occasions. This is evident from the international symposium that was held on September 3rd. After researching potatoes for a decade, scientists were able to make the potatoes resistant to Phytophtora by genetically engineering resistant genes in wild potato species (DuRPh). The DuRPh research was financed by the Dutch government.
The potato is the third largest food crop in the world and the most important arable crop in the Netherlands. A lot of pesticides are used on potato crops, more than on other crops. Growers use these pesticides mainly for protecting the crops against late blight, which is caused by Phytophtora infestations. This pathogen is genetically seen as very 'plastic': there is a lot of genetic variation present which make it easy for new forms of the pathogen to develop. This kind of genetically plastic pathogen can quite easily break through the defences of resistant plants.
Conventional potato crops must be sprayed with fungicides 10 to 15 times a year to keep the disease at bay. This impacts the environment. Controlling late blight (and yield losses) costs Dutch growers around € 100,000,000 (one-hundred million) per year. That's almost 20% of production costs. Worldwide, late blight (crop losses plus mitigation costs) is costing billions of dollars.
In the ten year DuRPh research program they have developed prototypes from potato varieties that are resistant to late blight. Effective resistance management was also developed during the research, whereby the genetic variation of the pathogen is monitored throughout the Netherlands. By combining these two approaches, the use of fungicides can be reduced by up to 80%. The research was financed by the Ministry of Economic Affairs, and carried out by Wageningen University.
According to international scientists who were present at the symposium on September 3, 2015, the results from DuRPh can be used for other major food crops as well. There are more crops that have problems due to one or more pathogens, such as wheat and bananas. Wild species with resistant genes are likely to be found.
Resistant varieties of crops, other than potatoes, can also hold their resistance long term by: multiple resistant genes from wild species being combined via genetic modification, monitoring the pathogen well and adjusting the combination of resistant genes in a timely manner. This can occur even if the pathogen is very diverse and can easily adapt to the resistance of the plant.
More information:
Wageningen Universiteit
Erik Toussaint, persvoorlichter,
T: 06 51 56 59 49