High-throughput screening of physical-mechanical berry skin traits facilitates targeted selection of breeding material with resistance to Botrytis bunch rot and grape sunburn
The ongoing climate change implies an increasing mean air temperature, which is signified by weather extremes or sudden changes between drought and local heavy rainfalls. These changing conditions are especially challenging for the established grapevine varieties growing under cool climate conditions due to an increased risk for fungal diseases like downy mildew (DM) and Botrytis bunch rot (BBR) as well as for grape sunburn. To meet that demand, the scope of most grapevine breeding programs is the selection of mildew fungus-resistant and climatic adapted grapevines with balanced, healthy yield and outstanding wine quality. Since no resistances or candidate genes have yet been described for BBR, physical-mechanical traits like berry size and thick, impermeable berry cuticles phenotyped with high-throughput sensors represent novel effective parameters to predict BBR. In a preliminary set of 16 grapevine varieties, we identified that the same physical berry traits, i.e. berry impedance and berry texture profiles, are correlated with the sensitivity of grape berries towards induced heat stress. Hereby, the variety-specific reaction to the controlled heat stress treatment is probably an indicator for grape sunburn tolerance. Within the cooperative project “WiVitis” the stated physical-mechanical traits will be phenotyped to characterize new and established grapevine varieties as well as recent elite breeding material from different breeding programs in the Upper Rhine region (Germany, France and Switzerland) growing under different local conditions. This spatial and temporal high-resolution dataset of berry skin traits will be used to verify transferability of BBR and sunburn prediction to unknown genotypes and environments followed by the screening of mapping populations for QTL analysis in order to develop reliable markers for BBR and grape sunburn.
Acknowledgements: We gratefully acknowledge Interreg (co-funding by the European Union) for funding the projects WiVitis and KliWiReSSE
Issue: ICGWS 2023
Institute for Grapevine Breeding Geilweilerhof, Julius Kühn-Institut, Siebeldingen, Germany