Innovative Methods for Assessing Drought Tolerance in Crop Varieties: Towards Sustainable VCU Testing in Austria

Progressive climate change is affecting agriculture in many ways. Increasing yield fluctuations and crop failures in particular are placing an economic burden on farmers. In addition, the general supply of sufficient high-quality agricultural products is also at risk. A key aspect is the increasing drought stress, which is noticeable across large areas and in various crop types. In Austria, Switzerland and Germany, temperatures have risen above average in global comparison. Since pre-industrial times, average temperatures in Austria have risen by 2.9°C, in Switzerland by 2.8°C and in Germany by 2.3°C. The summer months of June, July and August are particularly affected in Austria. Data collected by Statistics Austria on maize yields in the federal states already show a correlation between extreme temperatures – especially in August – and reduced yields. Global forecasts assume that today's maximum yield losses due to drought stress could become the new average within the next 30 years.

Against this background, the question arises as to how Austrian variety testing can adequately reflect this increasingly frequent abiotic stress in variety descriptions. A current attempt to classify the drought stress tolerance of varieties is the DROST research project (‘Methods for Evaluation of Drought Stress Tolerance in VCU Testing’). Using maize and winter wheat as examples, variety trials from the value assessment that are regularly affected by drought are to be intensively sampled. Soil moisture will be monitored using data loggers and relevant weather data will be collected. An extended soil analysis will provide information not only on nutrient supply and soil quality, but also on water retention capacity. In addition to the usual phenotypic surveys in the value assessment, multispectral indices on the leaves will also be measured using a handheld device. Drone flights will be used to record various parameters such as chlorophyll content, leaf discolouration and biomass. In order to also take physiological processes within the plants into account, the protein profile of the grains at different stages of maturity will be examined using high-resolution LC-MS/MS to identify relevant marker proteins for drought stress, mostly enzymes. The plan is to sample three locations per crop type in Austria's Pannonian Plain over a period of two years. In addition, five varieties per crop type will be specifically exposed to drought stress in a rainout shelter and compared with an adjacent control area. Additional phenotypic and proteomic surveys are also planned here. Finally, a SWOT analysis will be carried out to evaluate the various survey methods. The aim is to develop a sound perspective for the implementation of efficient methods for assessing drought stress tolerance in Austrian variety testing. This should particularly benefit farmers, who will be able to rely on reliable, officially tested results.