EFFECTS OF SIMULATED DROUGHT BY POLYETHYLENE-GLYCOL ON BAHIAGRASS GERMINATION

The influence of accelerated aging (AA-48h @ 41 degrees C/100% humidit y) and simulated drought on the germination of Argentine and Tifton 9 bahiagrass (Paspalum notatum Flugge.) was studied. Seeds were subjecte d to AA and germinated in 0, -0.23, -0.32, -0.38, -0.43, -0.50, and -0 .52-MPa water solutions of polyethylene glycol to simulate variations in available soil moisture. Tifton 9 seeds had higher germination than Argentine seeds, especially with the AA treatment. Higher (P < 0.01) total germination occurred with AA seeds compared to the check for Arg entine (38.1% vs 30.0%) and Tifton 9 (72.3% vs 34.8%). For total germi nation, both grasses responded quadratically to increasing moisture st ress. Accelerated aging also increased the rate of germination for bot h grasses compared to the check seed. Highest predicted rare of germin ation for treated Tifton 9 seed was 5.1 d at an osmotic pressure of -0 .06 MPa. The Tifton cultivar appeared less sensitive to simulated drou ght than did the Argentine cultivar. Earlier, more uniform germination could be expected under field conditions for AA treated bahiagrass se ed. More favorable germination of treated seed in dry soil conditions may allow an increase in the period of the year for which bahiagrass p lanting could be recommended.