Carlos Augusto da Silva

Severity of leaf diseases in maize inbred lines with different kernel hardness in two sowing seasons

Resistance of maize inbred lines to major leaf diseases should be characterized for the development of new hybrids in breeding programs. Thus, this study aimed to assess the severity of leaf diseases in maize inbredlines with different kernel hardnessand two sowingseasons. We assessed four inbred lines and one check hybrid with dent kernels and four inbred lines and a check hybrid with flint kernels. Treatments were conducted in two sowing seasons, one in October, and another in December 2013. The symptoms of gray leaf spot (Cercospora zeae-maydis), northern leaf blight (Exserohilum turcicum), and white leaf spot (a complex of Phaeosphaeria maydis and Pantoea ananatis) were assessed every 10 days from flowering. The area under the disease progress curve was also calculated. Severity level of the diseases was higher in inbred lines when compared to the check hybrds (AG8041 PRO and P30R50YH), regardless of kernel hardness. Dent-kernel inbred lines showed a higher severity of northern leaf blight symptoms when compared to flint-kernelones. It is worth mentioning that disease severity increased as sowing was delayed.