Effect of culture media on the growth and morphology of Hungarian Macrophomina phaseolina isolates

Abstract

Macrophomina phaseolina (Tassi) Goidanich can cause serious yield losses in several plant species. Investigations were made on the colony morphology of fifty Macrophomina phaseolina isolates from Hungary, one from Spain and two from Serbia on six different culture media to detect differences between the isolates. The fungus exhibited the most intensive growth on maize-flour agar, followed by the Sabouraud-glucose, maltextract, potato-dextrose, Czapek-Dox and watery agar media. Investigations on the macromorphology of the isolates revealed different extents of aerial mycelia formation and differences in the zonal structure of microsclerotial formation on the individual media. One isolate (Mp 38) turned the Sabouraud-glucose agar medium pale pink. Investigations on the micromorphology of the cultures showed that the isolates also varied with respect to microsclerotial characters (size, shape and production of microsclerotia). The microsclerotia of this fungal pathogen had the greatest diameter (averaging 135.31 μm) on Sabouraud-glucose agar medium. This study was the first in Hungary to prove that Macrophomina phaseolina could be grown on nutrient-deficient watery agar, suggesting that it can tolerate a wide range of ecological circumstances.