Resistance in soybean varieties against charcoal rot disease caused by Macrophomina phaseolina

Soybean varieties which are in cultivation across the country were evaluated against charcoal rot (Macrophomina phaseolina) under field condition of high disease pressure and also by artificial cut stem inoculation technique using two aggressive isolates in poly house. In two years (2018 & 2019) field study, out of twenty two varieties, only three (JS 20–98, JS 20–34 and MAUS 162) were found to be absolutely/highly resistant whereas four (JS 20–69, NRC 86, MACS 450, PS 1225) showed moderately resistant reaction against the charcoal rot. Per cent mortality varied from 0.0 to 97.4 and 0.0 to 87.8 during 2018 and 2019, respectively. hundred per cent yield reduction was recorded in most of the charcoal rot affected plants. Regression equation{Y =-3.736 + X1(0.997), R²=0.9906} revealed that per cent unit rise in plant mortality can cause 0.997 per cent yield reduction in the soybean crop. In cut stem inoculation technique, none was found to be resistant against charcoal rot. Based on area under disease progress curve (AUDPC), both isolates were found to be positively correlated (r=0.670**) but significantly different in their aggressiveness.