Vernalization in wheat I. A model based on the interchangeability of plant age and vernalization duration

Vernalization treatments of 0 to 70 d initiated when 0 to 8 leaf tips were visible were applied to plants of the winter wheat (Triticum aestivum L.) cultivars Pioneer 2548 and Augusta. All plants headed irrespective of duration of vernalization. Unvernalized plants of Pioneer 2548 and Augusta had mean final leaf numbers (FLN) of 20.8 ± 1.3 and 21.7 ± 1.0, respectively. Increased duration of vernalization generally reduced FLN within an age...