Influence of seed and foliar applications of growth regulators on turfgrasses

The effects of propiconazole and seaweed extract seed treatments on the germination of Kentucky bluegrass (Poa pratensis L.) under osmotic and temperature stresses were determined in the laboratory. As polyethylene glycol (PEG) 8000 concentrations was increased from 50 to 250 g/L, percent germination was reduced. Propiconazole at 0, 0.5, 0.9, and 1.9 g a.i./kg of seed did not affect total germination, however, germination was delayed with propiconazole seed treatment. Plumule and radicle lengths of seedlings at the termination of experiment 21 days were inhibited with increasing PEG 8000 concentrations and propiconazole treatments.

Germination of seed treated with either propiconazole at 1.9 g a.i./kg of seed or seaweed extract at 13 g of product /kg of seed was determined under a range of temperatures from 15 to 40 C on a thermo gradient table. The optimum temperature for Kentucky bluegrass germination was at 25 C. Germination was decreased at temperature below 25 C and no germination was obtained at temperatures above 35 C. Seed treated with propiconazole or seaweed extract did not stimulate seed germination at the different temperatures.