Resistance Assessment of Hybrid Corn Genotypes to Major Corn Diseases and Its Effects on Disease Epidemic Components in South Sulawesi, Indonesia

Abstract

The use of resistant varieties is one of approach that can be used in the management of the pathogen development. This study aimed to examine the resistance level of hybrid corn genotypes to the corn major diseases and to determine its effect on the components of the disease epidemic. Testing for the three major diseases was carried out using spreader row plants as an inoculum source. Parameters observed in this study were disease incidence for downly mildew (DM), disease severity for maydis leaf blight (MLB) and leaf rust (LR), disease development model, infection rate, area under the disease progress curve (AUDPC), protection index, and path analysis. The results showed that the HBC01 genotype had the lowest attack intensity to DM, MLB, and LR, namely 35.55%, 37.33%, and 25.33%, respectively. The disease epidemic components also showed that the HCB01 genotype has the lowest AUDPC value and infection rate with the highest protection index against DM, MLB, and LR. Furthermore, relative humidity, temperature, rainfall, and wind velocity were correlated in influencing the development of DM, MLB, and LR. The conclusion is that the hybrid corn genotype greatly influences the development of epidemics of DM, MLB, and LR.