The use of tolerance as a form of control for soybean rust can be a viable alternative, since qualitative resistance has been shown to be unstable in function of fungal variability. This trial was carried out at in western Bahia in 2003/04, with the objective of assessing the tolerance of the main soybean (Glycine max) cultivars used in the area. Four early maturity cultivars [MG/BR 46 (Conquista), Emgopa 315, BRS Corisco and M-SOY 8411] and four cultivars of late maturity (BRS Barreiras, M-SOY 9350, FT 106 and BRS Sambaíba) were assessed. Tolerance was quantified by determining the difference of yield in subplots treated and untreated with fungicide. The cultivars MG/BR 46 (Conquista) and M-SOY 8411 did not present significant yield differences; however, this could not be attributed to tolerance in function of the low severity observed in this trial. This difference could be attributed to escape, since when the rust obtained higher values of severity, the two cultivars were already in the final stages of development. Although the maximum severity observed in this trial has been low (30.5% for BRS Barreiras), except MG/BR 46 (Conquista) and M-SOY 8411, the others cultivars assessed presented significant differences among the subplots treated and untreated with fungicide. This shows an absence of tolerance in the main cultivars commercially planted in western Bahia. It was observed that early maturity cultivars had inferior yield reductions than late maturity cultivars.
resistance; control; Glycine max
