Resumo

MARTINEZ-HILDERS, Andrea  e  LAURENTIN, Hernán. Phenotypic and molecular characterization of Macrophomina phaseolina (Tassi) Goid. coming from the sesame production zone in Venezuela. Bioagro [online]. 2012, vol.24, n.3, pp.187-196. ISSN 1316-3361.

Charcoal rot is a disease caused by  Macrophomina phaseolina, which is considered an important threat to sesame production in Venezuela. One of the strategies to control the pathogen is the use of genetic resistance, but for using it, it is required wide knowledge about its genetic variability. To characterize Macrophomina phaseolina coming from Venezuelan sesame production area, by using  morphological traits and molecular markers, some attributes were determined as growth velocity, microsclerotia production, mycelium colour, aerial mycelium presence, and RAPD by using 13 primers for seven fungus isolates collected from about 2500 km². Variability for growth velocity (0.70-0.93 mm·h^-1), microsclerotia production (18-56 in 100 μL) and aerial mycelium presence was observed. Mycelium colour was dark grey for all the isolates. Ten out of the 13 primers used were able to amplify the DNA, generating 81 bands (100 % polymorphic). Phenogram and principal coordinates analysis displayed a similar pattern for grouping the 7 isolates. There was not a consistent relationship between geographical origin and grouping based on RAPD, although there was a trend to separate isolates according to the margin of Acarigua River, from where they were collected.

Palavras-chave : Sesamum indicum; charcoal rot; RAPD; microsclerotia production; growth velocity.

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