INCIDENCE OF CHARCOAL ROT (Macrophomina phaseolina) IN MAIZE HYBRIDS IN DIFFERENT ENVIRONMENTS DURING OFF-SEASON

Abstract

Maize cultivation in Brazil can occur during the summer or off-season. Diseases are significant contributors to production losses. Charcoal rot (Macrophomina phaseolina) is the primary disease affecting off-season maize crops. This study aimed to assess the incidence of charcoal rot in commercially available maize hybrids under different soil water availability conditions during the off-season. The experiments were conducted at the Embrapa Research Facility, located at Invernadinha Farm. The experimental design was a randomized block design with three replicates. The first experimental crop was sown on February 21, 2022, in a red-yellow Latosol soil environment (Environment 1). The second was sown on March 3, 2022, in a Concretionary Petric Plinthosol soil environment (Environment 2). Ten hybrids were used in each experiment. Plant height was measured after the plants reached physiological maturity, and ten stalk samples were collected from each plot. Afterward, the microsclerotia of M. phaseolina were identified visually in the laboratory. Data are expressed as percentages and subjected to a joint analysis of variance. These results indicate that soil conditions of higher water stress, in conjunction with elevated temperatures, significantly enhanced the development of charcoal rot and directly affected plant productivity. A joint analysis of the environments revealed that the AS1820, AS1822, and  P3707 hybrids had the lowest average incidence of charcoal rot and the highest yields.