Temperature response and flowering of white clover (Trifolium repens) varieties in controlled environments and the field

Floral initiation of 10 white clover varieties growing in three controlled day/night temperature regimes, 22“/10°C, 20°/10°C, 17°/10°C, was recorded. Effects of artificial soil heating on floral initiation of the same plants subsequently transferred to the field were also examined. In the controlled environments only a slight increase in day temperature (2–5°C) was necessary to significantly increase flowering. Defoliation at the three temperatures had contrasting effects on subsequent flower production. Results from the soil heating experiment suggested that increased temperature might compensate for short daylengths, by bringing forward reproductive bud initiation by 1 month. Soil heating increased the total number of inflorescences produced.