Reação de genótipos de milho à mancha ocular causada por Kabatiella zeae

Abstract

The objective of this study was to evaluate the reaction of corn genotypes to eyespot caused by Kabatiella zeae under natural field conditions. The assay was carried out during the 2006/2007 growing season, in Pato Branco-Paraná State, consisting of 33 hybrids and two sowing seasons, on 10/13 and 12/27/2006, respectively; and in the 2007/2008 growing season, in the same place, with 10 hybrids and two sowing seasons, on 10/20 and 11/12/2007, respectively, and in Palma Sola-Santa Catarina State, with 8 hybrids and one sowing season, on 09/30/2007. Disease intensity was determined by means of severity evaluations. The observed corn plant reactions allowed genotypes with different levels of eyespot resistance to be discriminated. Hybrids AG 9020 and SPRINT were the most susceptible to the disease, while AS 1565 and DKB 234 were the most resistant; this behavior was repeated in both years and growing seasons. It was concluded that the variation in susceptibility to eyespot among the hybrids tested, may have been influenced by ambient conditions.