Characterisation of the Phenotypic Reaction of Brazilian Soybean Genotypes to Sclerotinia sclerotiorum Under Controlled Conditions

White mould is a disease caused by the fungus Sclerotinia sclerotiorum, and it is considered one of the most devastating diseases in soybean crops, causing huge losses in productivity. In this study, we aimed to contribute to the genetic control of this disease by characterising the phenotypic reaction of 67 Brazilian soybean genotypes to S. sclerotiorum under controlled conditions. Plants were artificially inoculated with mycelium discs when they reached the four-node phenological stage. Symptoms of white mould developed in all soybean genotypes. The resistance reaction was characterised by measuring the length of lesions on the main stem at 7 days after inoculation. Of the 67 genotypes evaluated, nine showed greater resistance to S. sclerotiorum, including 17S-01443-L8, 16S-00630-L4, GER_00003, 13S-00001-L2/FPS 2457 RR, BMX Torque I2X, P95Y02 IPRO, 17S-00842-L5, HO Pirap & oacute; IPRO and TMG 2359 IPRO. Twenty-three genotypes showed an intermediate response, while 35 genotypes showed greater susceptibility to S. sclerotiorum. Further studies should be conducted under field conditions with the soybean genotypes that showed greater resistance response to S. sclerotiorum under controlled conditions.