Over the last few years a field assessment method based on a colony-forming unit and stem and root severity was developed and this method has remained the only alternative option for screening and identifying resistance against charcoal rot. One major issue however, when using the field evaluation method, is the effect of plant maturity on the relative timing of symptom development. Late maturing soybean genotypes will not reach growth stage R7, the stage in which evaluations are usually performed, in similar environmental conditions as the earlier maturity groups, often producing confounding results. Testing of soybean lines under semi-controlled conditions in a greenhouse, lab or in controlled...