Influence of Temperatured uring Anthesis on Seed Set in Poa pratensis L.1

‘Newport’ Kentucky bluegrass (Poa pratensis L.) was subjected to temperatures of 21, 27, 32, 38, and 43C for time intervals of 1 to 6 days during anthesis. Effects of these treatments were measured by seed weight per head, weight of 100 seed, viability of pollen, percent of rioters setting seed, and seed germination. Increases in temperature above 27C during anthesis resulted in reduction for all measurements except seed germination. The decline was gradual as temperature increased, becoming significantly lower at 32C for most measurements and at 38 and 43C for all measurements. Increasing the length of exposure to high temperature during anthesis also resulted in a gradual decline in all measurements except seed germination. Differences were usually significant after 2 to 3 days of exposure to high temperature. Germination of seed produced was not significantly affected by high temperature or length of exposure to high temperature during anthesis.