Soybean (Glycine max) Purple Syndrome and its relationship with bioclimatic variables

Introduction. Cercospora leaf blight (TFC) and purple seed stain (MPS) are two endemic soybean (Glycine max) diseases in Argentina. Objective. Select the bioclimatic variables (VB) related to severity values greater than or equal to 90 % of the TFC and/or incidence greater than or equal to 50 % of the MPS in Argentina. Materials and methods. In the soybean region of Argentina during the years 2015 and 2023, 45 VB available in Worldclim (temperatures, precipitations and radiation) were used for modeling with the MaxEnt program. From the maps obtained in the modeling, the probabilities of a severity (SEV) of TFC ≥ 90 % and/or an incidence (I) of MPS ≥ 50 % were extracted for each geographical point evaluated in this experience, to later use them in the analysis. generation of multiple linear regressions. Results. Of the 45 VB analyzed, the ones that were most related to both diseases were rainfall and temperatures. Radiation was the VB with the least association both with the SEV of the TFC and with the I of the MPS Conclusion. The bioclimatic variables temperatures (between 25 °C and 30 °C) and rainfall between the months of December to April had the greatest associations with severity values greater than or equal to 90 % of the TFC and/or incidence greater than or equal to 50 % of the MPS in Argentina.