Reação de Genótipos de Palma Miúda (Nopalea cochenillifera) a mancha marrom causada por Macrophomina nopalii.

Abstract

The cactus prickly pear (Nopalea cochenillifera) is one of the main sources of food for cattle during dry periods in the Northeast region of Brazil. In the state of Alagoas, the crop stands out as the second most cultivated, surpassed only by sugarcane. Despite its hardiness, cactus pear is susceptible to several diseases, among which brown spot stands out, considered the most important in the region. Many pathogens are associated with this disease, especially species of the genus Macrophomina. Given the scarcity of studies focused on the resistance of cactus pear genotypes to brown spot, this study aimed to evaluate the reaction of different cactus pear genotypes to brown spot caused by Macrophomina nopalii. In the analyses, seedlings of six cactus genotypes, Clone 6, Clone 7, Clone13, Clone 21, Clone F-21 and Tamazunchale were used. Inoculations were performed by depositing PDA discs containing pathogen structures. In the controls, only PDA discs without fungal structures were used. The experiment was maintained in a greenhouse for up to ten days and evaluations were21 presented the smallest average lesion size, indicating promising behavior regarding resistance to brown spot caused by M. nopalii. performed by the diameter of the lesions in each replicate. Among the genotypes evaluated, Clone F-