Abstract

CHAVEZ, Alice; CAZAL, Cinthia  and  KOHLI, Mohan. Difference in the reaction to Pyricularia oryzae of wheat materials in the vegetative and reproductive stages. Investig. Agrar. [online]. 2017, vol.19, n.1, pp.56-63. ISSN 2305-0683.  https://doi.org/10.18004/investig.agrar.2017.junio.56-63.

The wheat blast caused by Magnaporthe oryzae B. C. Couch and L. M. Kohn (sin. Pyricularia oryzae), is currently considered one of the most important wheat disease in South America, considering the few sources of resistance reported in the world, the aim of this study was to relate Pyricularia oryzae resistance in leaves with the resistance in spikes, inoculating 61 wheat materials belonging to the National Wheat Program of the Instituto Paraguayo de Tecnología Agraria. These were selected based on their wide genetic variability. Inoculations were in greenhouse when the plants presented four leaves for the vegetative stage and in espogazon for the reproductive stage, using a suspension of 2.105 conidia/ ml from an isolate of fungus selected for its high virulence in previous trials. Of the 61 materials evaluated only four were resistant in leaf and in spikes, and three were resistant in leaf and moderately resistant in spikes, demonstrating the narrowness in the base of resistant germplasm for wheat blast infections in the spikes Based on the low number of lines considered resistant to Pyricularia in this study, the need to increase genetic resistance in wheat germplasm is urgently emphasized.

Keywords : Pyricularia oryzae; wheat blast.

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