BOTANICAL ASPECTS OF CEREALS FIG 2 10 Typical profiles of wheat grain weights within a towards the tip of the spikelet, and represented by o, A,t O.( Bremner and Rawson, 1978) aborts(Fig. 2. 12). Each fertile floret contains a single ovary; its style is not of the feathery type typical of most cereals but a long threadlike structure covered in fine hairs which entrap wind-borne pollen. A single ear may contain 800 fertile florets so the same number of stigmas or silks'is present The ear or cob is wrapped by modified leaf sheaths forming husks or shucks and the silks emerge together from the distal open end of the Perhaps the protection afforded by the husk spikelet. earl millet: a spike, b. part of spike enlarged, c protective husk(Fig. 2. 13) FIG 2.11 obviates the need for enclosure of the reproduc tive structures by bracts and pales. these are outbreeding habit fits it admirably for Fl hybrid insignificant in maize and as a result grains are production, whereby yields have been increased not separated one from another on the cob In dramatically through the heterosis or hybrid some cases their mutual pressure imposes an vigour which results angular form on them. While most cereals are dependent to some degree on cultivation for their Life cycle of cereals survival, maize has the ultimate dependence on man since there is no mechanism for dispersal of Although other parts of cereal plants have ts seeds remaining The concentration of the value, particularly in providing feed and bedding sexual organs on separate spikes encourages cross- for livestock, the ripe fruit or grains are economic pollination, which is the norm for maize. Its ally by far the most valuable parts of the plantc j_ II tl8- g 9- * 2 1 w a 10 12 11 0-l 14 15 13- 16 17 ie 19 20 I- % ** \* (b) - \e ‘It \.4 - 7) *i; 7- A\A \* \+ A \‘* - +/:,a - - f J1 */ I I 30 40 50 60