| Abstract: | The effects of three temperature regimes, 25°C day/20°Cnight, 20°C day/15°C night and 15°C day/10°Cnight upon seed development in S.22 Italian ryegrass, S.24 perennialryegrass, S.215 meadow fescue and a Swiss ecotype of meadowfescue were investigated. The largest ovaries and largest seedswere obtained from the 15/10°C environment and floret fertilitywas greatest at 20/15°C. The largest seed weight per inflorescencewas at 20/15°C, except for the Swiss ecotype of meadow fescuewhere it was greatest at 15/10°C. The percentage germinationwas highest from those seeds developed at 25/20°C and thiswas particularly marked at germination temperatures of 13–20°C.There was a low rate of germination of seeds from the 15/10°Ctreatment, but they produced seedlings with the largest dryweights. It is concluded that year to year temperature differenceswill affect the yield and quality of seed crops of forage grasses. |
