Abstract

The present findings on Glycine betaine provides significant perception on the dynamics of pearl millet by activating the host defense responses during its interaction with the pathogen. Glycine betaine treatment to seeds at 30 mg ml-1 concentration for 6 h significantly enhanced the seed germination and seedling vigor of pearl millet in comparison with the control. Significant inhibition of sporangial sporulation, zoospore release and motility was observed at 30 mg ml-1, even though it failed to exhibit complete inhibition in all the concentrations tested. TTC assay confirmed the declined release of sporangiospores from sporangia by inhibiting the viability of sporangiospores. Inducer treated seedlings recorded an early and increased hypersensitive response as a reaction to Sclerospora graminicola inoculation compared to untreated. The effect of Glycine betaine was tested by seed treatment alone, seed treatment + foliar application and foliar application alone. Significant inhibition of disease control was noticed in seed treatment followed by foliar application with 19.2% disease incidence at 30 mg ml-1. Spatio-temporal studies indicated that seed treatment with Glycine betaine increased disease protection three days after inoculation. With these results, Glycine betaine has been shown to be an effective compound for the control of downy mildew disease in pearl millet.

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