Murcha-de-Ceratocystis em Eucalipto : método de detecção não destrutivo e precoce da resistência e aspectos morfofisiológicos e anatômico da infecção

Abstract

Pathogen´s Ceratocystis fimbriata Ellis & Halsted causes wilt in Eucalyptus, it´s difficult to control systemic character and genetic variability of the isolates. The resistant material is the main control form. Thus, in the present work aimed to: 1) to study early and non-destructive phenotypic evaluation methodology in leaf discs of clones (E. grandis x E. urophylla), to eucalyptus resistance of the C. fimbriata infection. 2) to evaluate morphophysiological and anatomical responses to C. fimbriata infection in eucalyptus clones. Clones of AEC 1528, BA 7346, CO 1407, BA 6021 (six- months-old years) were used. First, 0.1 mL of fungus spores (2.5 X 106 mL-1 ) were inoculated in genotypes’s leaf disc (Ø2 cm), in the adaxial leaf surface, near midrib and kept in chamber humidity in an air-conditioned room. After, 6 days of inoculation the severity was evaluated. In order to compare this methodology, disks (Ø5mm) of MAEY with fungus’s mycelium. A cut lengthwise 2 cm length was made on the stem in 10 plants and seedlings control (without fungus). For both tests, frequency scale was used and different resistance levels were found, since high resistance until high susceptibility. In the second experiment, morphological analyzes, leaf and stem dry matter, height and stem diameter of the infected and uninfected clones were performed, and anatomical analyzes were performed at the lesion site and 3 cm before and after the lesion, of the mycelium of C. fimbriata growth avaliation in the xylem vessels, before and after 50 days, of the inoculation. It observed mechanism of resistance: gels, new tissues near the infection region.