Avaliação de genótipos de Panicum maximum Jacq. à cárie do sino e à mancha foliar

Abstract

Panicum maximum cultivars have shown great damage due to diseases, such as bell smut and leaf spot, caused by Tilletia ayresii and Bipolaris maydis, respectively. This study aimed to evaluate the reaction of genotypes of such forage grass to those diseases. The experiments were conducted at Embrapa Beef Cattle, in Campo Grande (MS), from February to July 2012. Disease intensities were weekly evaluated for 26 P. maximum genotypes. Among the evaluated genotypes, there were varied degrees of resistance to bell smut and leaf spot. Favorable environmental conditions of temperature and relative humidity were 16ºC to 27ºC and 62% to 88% for bell smut and 22°C to 27°C and 62% to 83% for leaf spot. Resistance to bell smut proved to be a heritable character and genotype PM40 behaved like the susceptible control, cv. Tanzânia-1, in relation to leaf spot. The management of P. maximum plants using standardization cut proved to be promising in the composition of control strategies to reduce leaf spot intensity.