Germination responses of creeping bentgrass (Agrostis palustris Huds.) and Kentucky bluegrass (Poa pratensis L.), and annual bluegrass (Poa annua L.) to elevated temperature were evaluated by germinating seed in sustained temperature regimes or by moving imbibed seed from high to intermediate or from intermediate to high temperatures. ‘Penncross’ creeping bentgrass germinated well at 40°/30°C (day/night) temperature or when moved from 40/30° to 25°/18° or from 25°/18° to 40°/30°. ‘Baron’ Kentucky bluegrass seed germination was decreased by 34°/28° and there was no germination at 40°/30°. Moving imbibed seed from 40°/30° to 24°/18° resulted in a high germination percentage, while imbibition for 12 or 24 hours at 25° resulted in some germination at 40°/30°. Annual bluegrass seed germination was significantly less at 34°/28° than at 25°/18° and was prevented at 40°/30°. Imbibition at 40°/30° prior to 25°/18° decreased germination and there was no annual bluegrass germination at 40°/30° regardlessf of pretreatments at 25° for up to 24 hours.
Received for publication Dec. 19, 1981.
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Research supported by a grant from the Canadian Golf Superintendents Association. The technical assistance of G. Rebick and N. Ross is gratefully acknowledged.