Osmopriming enhances pearl millet growth and induces downy mildew disease resistance

Abstract

The osmoconditioning effect on pearl millet seeds was tested with different concentrations among which 1% showed an optimum effect. Seeds osmoprimed with mannitol for 3 h followed by overnight drying offered maximum germination of 99% and seedling vigour of 1465 followed by PEG and glycerol. All the three osmopriming agents recorded a significant increase on growth parameters like height of the plant, leaf area, number of tillers per plant. The results indicated that mannitol offered a maximum positive effect followed by PEG and glycerol. Notably, osmopriming has advanced five days of flowering and also has a positive effect on number and length of the earheads. The osmoconditioning agent increased the 1000 seed weight significantly over the untreated control. When the osmoprimed seeds were germinated and inoculated with downy mildew pathogen, the maximum protection of 61.76% was observed in mannitol treatment followed by PEG and glycerol under greenhouse conditions. Osmopriming has promoted seed germination percentage, seedling vigour index and growth parameters in pearl millet and also reduced downy mildew incidence.