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Anthesis (flowering; DGS 60–69; Figure 1.11) usually occurs between three and eight days after ear emergence, starting in the lower florets of the central spikelets. Most flowering throughout the spike is often completed within two to four days, although late flowering in distal spikelets and florets can extend this period to seven days (Percival 1921). Wheat is mostly self‐pollinated, but some outcrossing is possible, particularly in genotypes with more open florets and when plants are grown close together. However, cross‐pollination is limited because wheat pollen is heavy and short lived.

Figure 1.12 Structures of a single mature spikelet. Gl = Glume; L = Lemma; P = Palea; Gr = Site of grain, obscured by lemma and palea; a = awn; IF = Infertile floret.

Figure 1.13 Ears (spikes) of wheats and their relatives.