Effect of nutrition on the vegetative and reproductive growth of the agent of floral and vegetative malformation of mango trees.
Terao D., Oliveira S. M. A., Tavares S. C. C. de H., Laranjeira D.
Author Affiliation: Área de Fitossanidade, Departamento de Agronomia, Universidade Federal Rural de Pernambuco, 52171-900, Recife, Pernambuco, Brazil.
Boletín Micológico 16 : 57-63
Abstract : Physiological aspects of the causal agent (Fusarium subglutinans [Gibberella fujikuroi var. subglutinans]) of the floral and vegetative malformation of mango (Mangifera indica) together with the optimization of pathogenicity tests, epidemic and control studies, make it possible to obtain thorough information in controlled environments. Considering that nutrition is, among the physiological aspects, one of the most important in the vegetative and reproductive growth of fungi, the present paper aims to evaluate the effect of different solid and liquid culture media (potato dextrose agar, oat agar (avena), V8 juice, Armstrong, Czapeck, mango extract) on mycelial growth, sporulation and dry weight of two F. subglutinans isolates (Iso-GV, from the vegetative bud and the Iso-GF, from the floral buds). The media that promoted the highest dry weights for the two strains were oat agar and V8. For both strains, the solid oat agar medium showed a low sporulation, in spite of the fact that a greater vegetative growth for the Iso-GV and a suitable growth for Iso-GF were induced. The Armstrong medium, both solid and liquid, promoted the highest sporulation. The effects of different combinations of carbon (starch, fructose, maltose and sucrose) and nitrogen (asparagine, peptone, potassium nitrate and sodium nitrate) sources on the behaviour of the phytopathogens revealed, in a general way, that both strains had a satisfactory growth in every carbon and nitrogen combination used, reaching their highest degree in the starch-sodium nitrate combination. In terms of sporulation, Iso-GV and Iso-GF had the highest production of conidia in the media with fructose-asparagine and maltose-sodium nitrate combinations, respectively.