The Or­ga­nic Out­door To­ma­to Pro­ject

Pro­ject de­scrip­ti­on

The organic outdoor tomato project was launched in 2003 with up to 34 trial varieties in Germany. The international cooperation includes research institutions, extension service, botanical gardens, commercial and amateur gardens.

Tomatoes are the most important vegetable both on global scale and in Germany. In Germany tomatoes are grown in almost every market garden, but only 15% of the demand are met. A major factor limiting the production are problems in outdoor cropping systems.

Outdoor production needs far less external input than the production in greenhouses or polytunnels. It is seriously impaired by late blight, a fungal disease caused by Phytophthora infestans. Thus, breeding for resistance is the major objective. Other important traits are fruit quality, chilling tolerance, nutrient efficiency, drought tolerance, and resistance against Alternaria solani and A. alternata.

List of va­rie­ties

Year of accreditation / Registration / Fruit weight

Resibella: 2019, by Culinaris, 50g
Rondobella: 2019, by Culinaris, 100g
Vivagrande: 2018, by Culinaris, 200g, Open source seeds licence
Sunviva: 2017, by Culinaris, 20g, Open source seeds licence
Primabella: 2012, by Culinaris, 30g
Clou: 2010, by Arche Noah, 35g
Dorada: 2010, by Arche Noah, 25g
Primavera: 2010, by Arche Noah, 25g
Resi: 2010, by Arche Noah, 20g

Li­te­ra­tu­re and the me­dia

  • Che, A., L, Erika, C., Naumann, M., Smit I., Horneburg, B., Pawelzik, E. (2021): Morphological, Leaf Nutrient, and Fruit Quality Characteristics of Diverse Tomato Cultivars under Organic Low-Input Management. Sustainability 2021, 13, 12326. doi: 10.3390/su132112326.
  • Zörb, C., Piepho, H.-P., Zikeli, S., Horneburg, B. (2020): Heritability and variability of quality parameters of tomatoes in outdoor production. Research, Bd. 2020, Artikel-ID: 6707529. doi: 10.34133/2020/6707529.
  • Mohammed, A.E., Smit, I., Pawelzik, E., Keutgen, A.J., Horneburg, B. (2019): Organically-grown outdoor tomato: fruit mineral nutrients, potential contribution to human diets and plant infection by Phytophthora infestans. Org. Agr. doi: 10.1007/s13165-019-00253-7.
  • Kotschi, J., Horneburg, B. (2018): The Open Source Seed Licence: A novel approach to safeguarding access to plant germplasm. PLoS Biol 16(10):e3000023. doi: 10.1371/journal.pbio.3000023.
  • Horneburg, B., Becker, H.C. (2018): Spontaneous outcrossing in tomato depends on cultivar and environment and varies between individual flowers. Plant Breed. 137:638–643. doi: 10.1111/pbr.12600.
  • Horneburg, B., Rehberg, M. (2017): Die Tomatensorte ‘Sunviva’ ist nicht patentierbar. Gemüse 11/2017:58.
  • Holzinger, A., Rehberg, M., Horneburg, B. (2017): Ökologisch produzierte Tomatenjungpflanzen für Hobbygärtner. Gemüse 9/2017:48–49.
  • Kotschi, J., Rehberg, M., Horneburg, B. (2017): Open-Source Seeds and the Tomato cultivar Sunviva. SAVE e-News 2/2017. url:
  • Kotschi, J., Rehberg, M., Horneburg, B. (2017): Open-Source Seeds und die Tomate Sunviva. SAVE e-News 2/2017. url:
  • Lerch, F., Horneburg, B. (2017): Paradeiser im Freiland. In: ARCHE NOAH Magazin (Hrsg.): S. 20–21
  • Steinschneider, C., Horneburg, B., Lerch, F. (2017): Freiland-Paradeiser in Österreich bei Befallsdruck durch Phytophthora infestans. In: Ländliches Fortbildungsinstitut Österreich (Hrsg.) Biogemüsefibel 2017:9–13. url:[tt_news]=374&cHash=9eaac78cb257eafc6abb04d4ef6c9e4e.
  • Hönigsberger, B., Antonelli, L., Samad, A., Horneburg, B., Trognitz, F. (2016): Genotype dependent microbiome of 60 different tomato cultivars. 67. Tagung der Vereinigung der Pflanzenzüchter und Saatgutkaufleute Österreichs 21.–23.11.2016, HBLFA Raumberg-Gumpenstein, Irdning, Österreich. url:
  • Wojciechowska, E., Weinert, C.H., Egert, B., Trierweiler, B., Schmidt-Heydt, M., Horneburg, B., Graeff-Hönninger, S., Kulling, S.E., Geisen, R. (2014): Chlorogenic acid, a metabolite identified by untargeted metabolome analysis in resistant tomatoes, inhibits the colonization by Alternaria alternata by inhibiting alternariol biosynthesis. Eur J Plant Pathol 139:735–747.
  • Klaedtke, S., Horneburg, B. (2012): Aromatische Tomatensorten trotz Krautfäule – auch in Luxemburg? Gaart an Heem Ausgabe Mai 2012: 132. Zeitschrift der "Ligue luxembourgeoise du Coin de Terre et du Foyer" (CTF).
  • Horneburg, B., Myers, J.R. (2012): Tomato: Breeding for improved disease resistance in fresh market and home garden varieties. In: Lammerts van Bueren, E.T., Myers, J.R. (Hrsg.). Organic Crop Breeding. S. 239–250. Wiley-Blackwell, Hoboken, NY, USA. ISBN: 978-0-470-95858-2.
  • Mohammed, A.E., Smit, I., Pawelzik, E., Keutgen, A.J., Horneburg, B. (2012): Organically grown tomato (Lycopersicon esculentum Mill.): Bioactive compounds in the fruit and infection by Phytophthora infestans. J Sci Food Agric 92:1424–1431.
  • Horneburg, B., Becker, H.C. (2011): Selection for Phytophthora field resistance in the F2 generation of organic outdoor tomatoes. Euphytica 180:357-367.
  • Horneburg, B., 2010: Participation, utilization and development of genetic resources in the Organic Outdoor Tomato Project. In: Goldringer I, Dawson J, Rey F, Vettoretti A (Hrsg.) Breeding for resilience: a strategy for organic and low-input farming systems? EUCARPIA 2nd Conference of the "Organic and Low-Input Agriculture" Section. S. 139–142.
  • Horneburg, B. (2010): Tomaten in menschlicher Gesellschaft. In: Brita Reimers (Hrsg.) Gärten und Politik. oekom verlag, München. S. 107–120.
  • Gladis, T., Horneburg, B., Suanjak, M. (2010): So was Krauses! ARCHE NOAH Magazin 4/2010:10–11.
  • Miles C, D. Inglis, B. Gundersen, P. Kreider, J. Roozen, B. Horneburg, D. Panthee (2010): Evaluation of late blight on tomato cultivars grown in the field, 2009. Plant Disease Management Reports 4:V126.
  • Horneburg, B. (2009): Chancen und Grenzen der Kulturpflanzenentwicklung im Praxisbetrieb - Tomaten im Freiland und Pastinaken. BIO AUSTRIA (Hrsg.): BIO AUSTRIA Bauerntage 26.–29.1.2009, Wels; Österreich: S. 77–79.
  • Horneburg, B., Watschong, L. (2005): Wildtomaten – mehr als eine Spielerei? Ludwig Watschong und Bernd Horneburg vom Dreschflegel e.V. sagen: Ja! Saaten & Taten 2006:94–9