ABSTRACT
Cultivated wheat belongs to the genus Triticum, subtribe Triticinae, tribe Triticeae. of the grass family (Gramineae). Of 30 species presently included in this genus only various species represent cultivated types. The inflorescence of wheat is a spike. Its main axis (rachis) is flat and sinuous, composed of short internodes, bearing the sessile spikelets alternately on opposite sides of the rachis. The wheat spikelet is an indeterminate structure bearing 2 to 5 perfect lower florets and 3 to 8 imperfect upper florets declining acropetally. The differentiation of the individual spikelets starts in the lower midpart of the spike and proceeds acropetally and basipetally. Anthesis usually starts in the basal florets of the central spikelets and proceeds basipetally and acropetally in the spike and acropetally within the spikelets. Spikelet initiation in the first and second tillers has been found to proceed at higher rates than in the main-shoot tiller, resulting in a reduced within-plant intertiller difference in floral development.
