Despite a massive drop in the area planted with sour cherry over the past 10 years, this berry is the base of one of the largest berry productions in Denmark, second only to blackcurrant. But organic sour cherries are rare in Denmark. Only one certified grower is registered and this is something scientists at Aarhus University are doing something about. A new project uses advanced methods to find suitable varieties that can foster the production of organic sour cherries.

The starting-point for this is a unique collection of 3500 hybrids of the best Danish and foreign sour cherries grown in the fields at Research Centre AU Aarslev near Odense. The scientists will develop new highly valid methods to record phenotypic resistance to diseases in sour cherries and combine this with the most advanced methods of identifying the metabolites that supposedly provide resistance to diseases. This will be achieved by developing a new identification method for resistance, where the links between the resistance recorded phenotypically and the plant profile of secondary metabolites will be found using high-field Nuclear Magnetic Resonance analysis (NMR metabolomics).

The challenge for sour cherries is fungal disease – particularly cherry leaf spot and brown rot, which have made the development of organic sour cherry productions difficult.

- Our hypothesis is that it is the combination of a number of metabolites that furnishes the resistance to fungal diseases. A model based on metabolomics is expected to make future screening for disease resistance more valid and potentially independent of expensive and uncertain resistance studies in the field, explains Martin Jensen, who is responsible for the project and a senior scientist at Aarhus University.

If the search for suitable varieties of sour cherries is successful, the project partners (that in addition to Aarhus University include Vesterskovgaard nursery, Horticultural Advisory Service A / S, Frederiksdal estate and Hedegaard's organic lamb and sour cherries) expect that the interest for cultivating organic sour cherries will grow. In the project the best clones will be propagated in collaboration with the country's largest producer of fruit trees, and these clones will then be further tested by the growers.

- With new good organic varieties we think it is possible to convert 300 hectares from conventional sour cherry production to organic sour cherries over the next 10-15 years. How quickly this happens depends on how many new plantings there will be, says Martin Jensen.

The project "Disease-resistant varieties for organic sour cherry production via NMR metabolomics analyses" runs until the end of 2016. The project has received 1.77 million DKK from the Green Development and Demonstration Programme under the Ministry of Food, Agriculture and Fisheries.

Further information: Senior scientist Martin Jensen, Department of Food Science, telephone: +45 8715 8331, email: martin.jensen@agrsci.dk