Approximately eight years have elapsed since stem canker (Phomopsis phaseoli f. sp. meridionalis/Diaporthe phaseolorum f. sp. meridionalis) became a limiting factor in soybean production in areas where this disease has spread. The most economical means of control is by the use of resistant cultivars. In an experiment conducted in greenhouse at Campinas, State of São Paulo, Brazil, with the objective of studying the effect of levels of potassium on the control of stem canker, two plants of soybean cultivar IAS-5 showed to be free from this disease. The seeds of these two plants were increased and plants were further inoculated with D. phaseolorum f. sp. meridionalis. After three generations all the inoculated plants showed to be highly resistent and were designated as IAC/IAS-5. It will replace IAS-5 which is moderately tolerant to stem canker and is the most grown in the State of São Paulo.
Glycine max; Phomopsis phaseoli f. sp. meridionalis; Diaporthe phaseolorum f. sp. meridionalis