INCIDÊNCIA E CARACTERIZAÇÃO MORFOLÓGICA DE Alternaria alternata E Bipolaris bicolor EM SEMENTES DE TRIGO ‘BRS 264’

Abstract

The seeds are considered important spread vehicles of pathogens.This study aimed to quantify the incidence of A. alternata and B. bicolor in wheat seeds ‘BRS 264’ and to perform morphological characterization of these fungi. Therefore, four sanitary evaluations were performed in gerbox transparent acrylic boxes. In order to inhibit germination, the seeds wereincubated in a BOD at 25ºC and 12-hour light period for 24 hours and, then, transferred to freezer at -20ºC and dark period for 24 hours. Just after, the seeds were incubated in BOD chamber at 25ºC and 12-hour light period during 8 days, which the incidence was estimated daily. Then, semi-permanent slide mountings were prepared for subsequent capturing images and measurement of fungi structures by obtaining 30 measurements of each structural component evaluated under a Leica DM500 light microscope, using the LAS EZ 2.0 (100x) software. The results concerning fungal structures and incidence were submitted to variance and regression analysis, respectively. From this, it was possible to confirm A. alternata and B. bicolor presence through morphological characterization, which presented 41.5 and 16.5% of incidence on the seeds at 8 days of evaluation, respectively.