Julius Kuehn Institute - Institute for Grapevine Breeding Geilweilerhof
Scientific portrait
Our research
Crop plants are key components for the value chain in agriculture, horticulture, and forestry. Consequently, they are the main focus of the JKI's research and legal activity. The Julius-Kuehn Institute (JKI) actively integrates the challenges of climate change into the development of agricultural production strategies that are resource-efficient, commercially feasible, and socially acceptable. More specifically, the institution aspires to create resilient and fruitful agroecosystems, provide concepts and strategies for the protection of cultivated plants, and strengthen the ability of our crop plants to withstand and endure biotic and abiotic stress.
Plant breeding can provide effective, long-lasting solutions to different problems such as site adaptation and pest management that are both economical and sustainable.
Grapevine breeding is, thus, most crucial in combating the impacts of climate change and ensuring yield. The JKI - Institute for Grapevine Breeding Geilweilerhof fulfills manifold tasks and focuses, e.g., on the development of novel grapevine varieties that are resistant to the most prevalent fungal pathogens while also addressing issues caused by climate change and the related pre-breeding research. One question our institute tries to answer: Do genetic resources of grapevines harbour positive traits that can be implemented into breeding? And how can these traits be utilised for breeding research to promote sustainability and climate adaptation without compromising wine quality and quantity? To answer these questions, the institute aims to identify the grapevine genomic regions linked with the relevant biotic and abiotic stress traits to follow their inheritance by using linked molecular markers. On the other side, the high-throughput phenotyping and digitalisation research groups are actively improving the efficiency of the pre-breeding research and breeding programmes.
Our contribution to Kliwiresse
The objective, in this case, is to build the base for the future development of grapevine varieties that can cope with climatic changes and heat stress. The development of such novel resistant cultivars and the understanding of the mechanisms will pave to way towards a viticulture that is more environmentally and economically viable. Over the last few years, winegrowers were progressively confronted with yield loss from heat stress-induced sunburn on grapes. To phenotype the resilience to heat stress, the JKI has already developed a technique for inducing heat stress (sunburn-like) damage in the lab using a high-throughput approach (Herzog et al., 2023, in preparation). The primary contribution to the project is establishing and optimising a novel heat-stress phenotyping pipeline (including controlled UV treatment), followed by the development of an artificial intelligence-based tool for the quantification of the trait.
Subsequently, in addition to the phenotyping data, genetic mapping, and QTL analysis of sunburn resilience in the lab and field will be conducted. These results will eventually help us in understanding resilience to heat stress. The development of molecular markers in QTL regions will afterwards enable the efficient development of novel grapevine cultivars with better adaptation to climate change through the use of marker-assisted selection in the breeding program. Additionally, we will incorporate the findings and understanding of climate change resistance that our project partners acquire through KliWiReSSE into applied breeding of new grapevine varieties.
Results to date
How have we proceeded?
Studying grape berry sunburn is important for future proofing the wine industry. By gaining insights into its causes and effects, winemakers can safeguard vineyard productivity, preserve wine quality, and adapt to evolving environmental conditions. The pursuit of developing, optimizing, and establishing a novel laboratory-based heat stress protocol holds paramount significance within the scientific community. Central to this endeavour is the imperative to replicate field conditions accurately. Given the inherent variability of weather patterns and the inherent challenges associated with ensuring consistent environmental conditions in the field, the creation of a controlled laboratory setting assumes critical importance. Secondly, the establishment of a standardized laboratory-based heat stress protocol empowers scientists to conduct reproducible experiments across different research settings and geographic locations. By bridging the gap between controlled laboratory experimentation and field observations, this endeavour promises to unlock new insights into the complex dynamics shaping grapevine physiology and resilience in the face of climatic challenges.
Our toolbox
We have achieved a milestone in our research endeavours by successfully establishing a laboratory-based heat stress pipeline. Concurrently, we have devoted considerable effort towards elevating its efficiency to a high-throughput paradigm, achieved through the integration of a sunburn test coupled with a state-of-the-art, high-quality image acquisition system. Leveraging this enhanced platform, we have conducted screenings on a selection of reference grape varieties, namely Riesling, Chardonnay, Pinot Noir, Weissburgunder, and Bacchus, alongside PIWI varieties including Calardis Blanc and Calardis Musqué.
The inclusion of these reference varieties serves a dual purpose: not only do they furnish reliable benchmarks within the sunburn assay, but they also offer insights into varietal responses to sunburn. Furthermore, our investigations have extended to a biparental population, comprising a progeny resulting from the cross between the sunburn-resilient Vitis sylvestris Hördt29 and the susceptible cultivar 'Tigvosa', alongside several accessions of Vitis sylvestris sourced from the Ketsch region. Remarkably, the outcomes obtained from our laboratory-based assessments exhibit a commendable concordance with field-based phenotyping data, underscoring the robustness and predictive validity of our approach.
How does heat tolerance of the berry develop?
Grape berries possess several inherent mechanisms that confer protection against sunburn, crucial for their development and ripening. One primary defense mechanism is the grapevine's canopy structure, which provides natural shading for the berries, shielding them from direct sunlight exposure during peak solar intensity. Additionally, the waxy cuticle covering the grape's surface acts as a barrier, reducing water loss and reflecting excess solar radiation. Furthermore, the presence of anthocyanin pigments within the grape skin offers photoprotection by absorbing harmful ultraviolet (UV) rays, thereby mitigating potential sunburn damage. Lastly, the vine's ability to regulate transpiration through stomatal control aids in maintaining optimal berry temperature, preventing overheating even under intense sunlight. Collectively, these factors contribute to the resilience of grape berries against sunburn, ensuring their successful maturation and harvest.
Recent publications relevant to the project
Töpfer R, Trapp O (2022). A cool climate perspective on grapevine breeding: climate change and sustainability are driving forces for changing varieties in a traditional market. Theoretical and Applied Genetics 135, 3947-3960
