Evaluation of the resistance mechanisms of new fungus-resistant grape varieties and their influence on the savings potential in crop protection

Project duration: November 2018 to October 2021

Funded by the Research Ring of the German Viticulture (FDW)
This project is being worked on as part of a doctoral thesis by Chantal Wingerter.

Contact persons:  

• Chantal Wingerter; Raum A2-160; chantal.wingerter@8< SPAM-protection, please remove >8dlr.rlp.de
• Prof. Dr. Jochen Bogs; Raum A2-161; jochen.bogs@8< SPAM-protection, please remove >8dlr.rlp.de

Summary

Viticulture all over the world is based on traditional European grapevine cultivars, but the problem is that these cultivars are susceptible to fungal pathogens like powdery mildew or downy mildew. To control the damage of these pathogens high amounts of fungicides or copper have to be applied to reduce the enormous crop yield losses. One way to reduce the use of fungicides is to increase the cultivation of fungus-resistant grape varieties. For this purpose, Native American or Asian wild grapes which have resistance properties against powdery and downy mildew are used as crossing partners for susceptible European grapes. By growing such new varieties, the development of viticulture can be improved in terms of factors such as sustainability, resources and environmental protection.

In this project, new fungus-resistant grape varieties are being examined with regard to their resistance against powdery mildew and downy mildew. Thereby, different plant protection variants for fungus-resistant grapes with different resistance traits are tested and disease incidence and disease severity are evaluated over three years. On the basis of the results, recommendations for the treatment of new fungus-resistant grape varieties are given which contribute to a sustainable plant protection and which reduce the fungicide input meaningfully. Thus cultivation of these varieties can be supported.

Furthermore, the resistance mechanisms of selected fungus-resistant grape varieties against downy mildew are investigated. The findings of the different defense mechanisms and the associated resistance loci should help to better understand the molecular basis. Based on this, the stability and durability of the defense mechanisms against aggressive isolates of downy mildew have to be assessed in order to ensure sustainable resistance management and breeding.