Organic plant breeding: These tomato varieties defy wetness

In the ecological open field tomato project at the University of Kassel in Germany, scientists have been breeding tomatoes together with professional and amateur gardeners since 2003. The resulting nine varieties can be freely used as so-called open source varieties without licence fees.

Five of these varieties should be largely resistant to the fungal disease late blight. For them, the recent wet summer was a litmus test.

"The previous years 2018 to 2020 were favourable for growing tomatoes outdoors in almost all areas of Germany," said Bernd Horneburg, who led the breeding project. Because it was dry and hot, fungal infestation hardly played a role. That was different this year. "In many gardens, varieties with low or medium resistance were so badly damaged that the yield remained low. Commercial cultivation in foil tunnels and unheated greenhouses was also severely damaged in some cases," Horneburg reported. The project varieties, on the other hand, were able to extend the season and greatly increase the yield. The agricultural scientist attributed this to the broad-based breeding with many participants: "Through participatory breeding in a wide variety of locations, it is possible to develop varieties that can cope with strongly changing climatic conditions."

One of the people involved is Herwig Scholz from the organic fruit farm Scholz-Döbelin, which is part of a solidarity farming scheme in the Lower Rhine region: "With the visible successes in outdoor cultivation, we can achieve supply around the year. For this purpose, passata or whole fruits are preserved for the winter."

Related links:

Tomato project website

Distribution of the project varieties via Culinaris webshop