Cold‐Stressed Soybean Sensitivity to Charcoal Rot

This study investigated the susceptibility of early-vegetation cold-stress soybean to Charcoal Rot (Macrophomina phaseolina (Tassi) Goid) previously isolated from industrial hemp (Cannabis sativa cv. Fibranova). Nine soybean cultivars were subjected to three-day cold stress in a walk-in growth chamber starting when the soybean had a fully developed first trifoliate, i.e. 20 days after sowing (DAS). The infection was performed on cold-stressed soybeans and soybeans grown in optimal conditions at 30 DAS. The infection lesion length was measured every three to four days. Cold stress significantly affected the intensity of the symptoms compared to soybeans grown in optimal conditions for all except the S9 cultivar. There were also significant differences between cultivars in their infection response.