Period, subculture number and culture color influence on the isolated Magnaporthe oryzae sporulation at the Tocantins State

Abstract

The fungus Magnaporthe oryzae, that caused the blast rice disease, present several restrictions for cultivation under laboratory conditions. Any characters can be variable even for the same isolate and need adaptations or innovations of the researchers for experimental development. This work aimed to verify the M. oryzae monosporic isolates of the IA-1 race collected at Projeto Rio Formoso, Formoso do Araguaia Municipality, the period of the cultures stored under laboratory conditions, the maximum quantity of the subcultures to keep the production of the conidia for the colonies satisfactory and the relation of different culture colors in BDA medium with the conidia production. For that, three experiments were carried out in complete randomized design. In the Experiment I, the cultures with 10, 14, 18, 22, 26 e 30 days after subculture were used. In the Experiment II, the cultures with 0, 1, 2, 3 and 4 subcultures from the original culture were used. In the Experiment III, the cultures were classified as Black, Center ash with wide white edges, Ash, Center ash with narrow white edges and White. Higher sporulation of the M. oryzae was obtained on the cultures with 14 days after the subculture, in the second subculture and on the black color.