Soybean is the major crop for high-protein feed and food in Europe, however domestic production is low due to non-adapted varieties for drought events and time to maturity. Especially, drought stress during growing season can cause severe yield loss in soybean. The present work focused on phenotyping of European soybean varieties of maturity groups (MG) 000 – I, grown in Tulln (Austria) under rainfed conditions. Phenotyping traits were visually scored and screened by hyperspectral and thermal imaging (TIR) techniques. Varietal differences in time to flowering, time to maturity (ttm), plant height, stomatal density, yield, 16 hyperspectral reflectance indices and canopy temperature were examined. Furthermore, TIR method was evaluated for two daytimes (12:00h, 15:00h) and applied for simplified Crop Water Stress Index (siCWSI). Results showed significant differences in ttm between MG. Plant height showed a positive relationship with ttm, while yield reached an optimum at MG 00. Stomatal density of European soybean varieties was published first time: stomatal density was significantly different and ranges between 203.4 and 322.2 stomata/mm². Soybean of MG 000 showed significant correlation between yield and chlorophyll index, red edge inflection point, water indices WI-1, NWI-2 and NWI-4. Later maturing soybean sets had less relationship between indices and yield. Correlation between siCWSI and morphological traits were higher at 15:00h than at 12:00h. Plant phenotyping is a crucial process to improve genetic material due to drought tolerance and ttm and predicting yield. These findings will contribute to a better understanding of varietal differences in European soybean varieties.

Soybean is the major crop for high-protein feed and food in Europe, however domestic production is low due to non-adapted varieties for drought events and time to maturity. Especially, drought stress during growing season can cause severe yield loss in soybean. The present work focused on phenotyping of European soybean varieties of maturity groups (MG) 000 – I, grown in Tulln (Austria) under rainfed conditions. Phenotyping traits were visually scored and screened by hyperspectral and thermal imaging (TIR) techniques. Varietal differences in time to flowering, time to maturity (ttm), plant height, stomatal density, yield, 16 hyperspectral reflectance indices and canopy temperature were examined. Furthermore, TIR method was evaluated for two daytimes (12:00h, 15:00h) and applied for simplified Crop Water Stress Index (siCWSI). Results showed significant differences in ttm between MG. Plant height showed a positive relationship with ttm, while yield reached an optimum at MG 00. Stomatal density of European soybean varieties was published first time: stomatal density was significantly different and ranges between 203.4 and 322.2 stomata/mm². Soybean of MG 000 showed significant correlation between yield and chlorophyll index, red edge inflection point, water indices WI-1, NWI-2 and NWI-4. Later maturing soybean sets had less relationship between indices and yield. Correlation between siCWSI and morphological traits were higher at 15:00h than at 12:00h. Plant phenotyping is a crucial process to improve genetic material due to drought tolerance and ttm and predicting yield. These findings will contribute to a better understanding of varietal differences in European soybean varieties.

2025. The unexplored diversity of rough-seeded lupins provides rich genomic resources and insights into lupin evolution. Legume Hub. https://www.legumehub.eu

Susek K, Vincenzi L, Tomaszewska M, Kroc M, Franco E, Cosentino E, Limongi AR, Tanwar UK, Jamil H, Nelson MN, Bayer PE, Edwards D, Papa R, Delledonne M, Jackson SA. The unexplored diversity of rough-seeded lupins provides rich genomic resources and insights into lupin evolution. Nat Commun. 2025 May 10;16(1):4358. doi: 10.1038/s41467-025-58531-w.