Phenotypic diversity of key adaptive traits in advanced Nordic and Baltic spring wheat (Triticum aestivum L.) breeding material

Wheat (Triticum aestivum L.) has become the most widely grown cereal crop in the Nordic-Baltic region, but due to climate change, its yields are under increasing risk. Here we present results of an international effort to use available wheat germplasm from the region to identify tools and genotypes for breeding wheat varieties with improved stability. We formed a panel of 300 spring wheat genotypes from the Nordic-Baltic region and studied their phenotypic diversity across environments to identify genotypes with high potential for adaptation to a changing climate. Field experiments were carried out in 2021 and 2022 in Estonia, Latvia, Lithuania and Norway. The performance and stability of yield (GY), protein content (PC), thousand kernel weight (TKW), test weight (TW), length of growing period (GP), and nine other traits were studied. Drought and excessive rainfall occurred in the Baltic countries in 2021–2022, whereas the weather in Norway was more stable. High variability for most traits, and significant GxE effects for all studied traits, were identified. We identified stable genotypes combining yield and quality using the AMMI model-based Weighted Average of Absolute Scores index (WAASB). Finally, we selected nineteen superior genotypes that combined high yield with high values of important quality traits. Thus, combining broad Nordic-Baltic wheat germplasm with extensive field phenotyping, we identified promising breeding material to develop climate-ready spring wheat varieties for the region.