“…Variation in S. sclerotiorum isolate aggressiveness has been reported previously on numerous crop hosts, including sunflower (Ekins et al, 2007;Otto-Hanson et al, 2011;Taylor et al, 2015;Denton-Giles et al, 2018;Yu et al, 2020;Rather et al, 2022). We observed only a modest correlation between isolate aggressiveness on the two sunflower inbred lines, consistent with observations of genotype-isolate interactions for S. sclerotiorum isolates evaluated on crop hosts such as soybean, canola, and sunflower (Davar et al, 2011;Ge et al, 2012;Willbur et al, 2017;Buchwaldt et al, 2022). Resistance to S. sclerotiorum is quantitative rather than governed by single, dominant resistance genes characteristic of genefor-gene interactions commonly observed in plant interactions with biotrophic pathogens.…”