Soybean genotypes resistant to white mold in the field and in oxalic acid sensitivity tests

Abstract

White mold, caused by the fungus Sclerotinia sclerotiorum, is considered the second most destructive disease affecting soybean crops. The pathogen is controlled by integrating different methods, including genetic resistance. However, genotype selection techniques often lack the desired efficiency.  As such, the aim of this study was to use sensitivity to oxalic acid as a selection method for white mold-resistant soybean genotypes and compare the results against soybean S. sclerotiorum infection in two agroecosystems, namely Barreiras (Bahia state – BA) and Jataí (Goiás state – GO). Eleven genotypes were planted and evaluated in the Barreiras region and 10 in Jataí, three of which were common to both areas. Assessments in the field involved analyzing white mold incidence, growth cycle and yield. For the oxalic acid-based selection method, the soybean genotypes were exposed to a 20 mM oxalic acid solution and wilting was assessed.  In oxalic acid sensitivity testing, both the resistant and susceptible genotypes mirrored the resistance expressed under field conditions. Thus, oxalic acid sensitivity testing was considered suitable for use in breeding programs aimed at selecting white mold-resistant genotypes.