Abstract

ENRIQUE MANUEL, Acuña Gamarra¹  and  CRISTHIAN, Grabowski Ocampos. Induction of resistance in wheat plants (Triticum aestivum L.) to the yellow spot (Drechslera tritici-repentis) and brown spot (Bipolaris sorokiniana). Investig. Agrar. [online]. 2012, vol.14, n.2, pp.71-79. ISSN 2305-0683.

The induction of resistance is the activation of defense mechanisms in plants; these are expressed after contact with the pathogen or exposure to some substances. To determine the induction of resistance to the yellow spot (Drechslera tritici- repentis) and the brown spot (Bipolaris sorokiniana) in wheat, experiments were conducted in the Department of Plant Protection at the Facultad de Ciencias Agrarias, Universidad Nacional de Asunción, San Lorenzo, Paraguay. Experiment 1: The first experiment determined the insensitivity of pathogens to the products Ka’a he’e, Acibenzolar – s – methyl (ASM), Fosetyl – Al and the mixture of trace elements + vegetable extracts (MOEV) at concentrations of 0.0, 0.14, 0.28, 0.36, 0.50%, where the observed variable was the mycelial growth after 12 days of incubation at 25 ± 1 °C. The second experiment determined the severity index in plants treated with potential inducers and inoculated with the suspension of 4 x 105 spore ml-1 of both pathogens. Data were subjected to analysis of variance and linear regression. The Ka'a he’e extract did not present direct inhibitory effect on the pathogens and reduced by 50% the rate of leaf spot severity, characterized as a potent inducer of resistance in wheat plants, while products MOEV and ASM presented a low direct effect and reduced in 48% and 33% the intensity. Finally, with the use of Fosetyl – Al was observed a significant reduction of fungal mycelium, decreasing 46% the severity index, these were considered as double effect products.

Keywords : Bipolaris sorokiniana; Drechslera tritici- repentis; induction of resistance,; yellow spot,; brown spot.

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