Induced systemic resistance and promotion of wheat and barley plants growth by biotic and non-biotic agents against barley yellow dwarf virus

Abstract

Barley yellow dwarf virus (BYDV) is an important virus infecting wheat and barley plants and transmitted by several species of aphids in Iraq. Pseudomonas fluorescence and Azospirillum irakense at 10⁸ CFU/ml, Sea force extract and Elsa fungicide at 1 ml/L were used to induce resistance in the plant against BYDV. The four elements were applied before and after virus-plant inoculation. Results show that all elements stimulated plant growth as estimated by plant heights and chlorophyll concentrations, and elicited significant reduction in disease incidence as determine by BYDV-disease scoring symptoms. The applications of these elements twice (before and after virus inoculation) were found to be more efficient in promoting plant growth and reducing virus disease score. The plant heights, chlorophyll concentrations and BYDV-disease scores were 82.25, 85.59, 74.38, 76.26 cm, 54.19, 45.81, 47.98, 47.85 μg/cm² and 2.0, 3.2, 2.8, 3.3 for P. fluorescence, A. irakense, Sea force extract, and Elsa fungicide treatments, respectively as compared to 62.08 cm, 38.10 μg/cm² and 1.2 in control treatments for the same parameters. P. fluorescence was more efficient in reducing disease incidence (2.0) as compared to 3.2 with A. irakense, 2.8 with Sea force extract, 3.3 with Elsa, and 5.4 with control. The partially resistant lines, (IBA 99, Arivate and Karonea) were found to be more responsive to treatments than the susceptible ones (Hashmia and Kara).

Key words: Sea force extract, barley yellow dwarf virus, Azospirillum irakense, Elsa fungicide.