Structure of wheat

Wheat - structure and genetics

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For those who aren't familiar with the anatomy of an 'ear' of wheat...

The ear consists of a number of individual spikelets (flower heads) set one above another along a length of stem known as the r(h)achis. Each spikelet has a single set of glumes (sheaths) enclosing up to 8 grains (each developing from a flower); each grain is enclosed in its own glumes (the lemma and palea). The glumes may have long dorsal to terminal bristles known as awns but this is now rare in modern wheat. The number of flowers/spikelet is an important character in identifying spp of wheat. Whether or not the grains are easily released from the glumes is another: 'hulled' wheats have strong glumes which hold the grains in the spikelets; 'naked' wheats are easily released even from the lemma and palea. The ease of release has implications for timing of harvest, ease of threshing, and resistance to disease/predation.

And the genetics... wheats may be diploid (14 chromosomes), tetraploid (28 chromosomes), or hexaploid (42 chromosomes). The more chromosomes, the easier it is to breed varieties suitable to local soil and climate.

Einkorn aka Small Spelt:
Emmer: aka Small Spelt:
Spelt aka Large Spelt:

Sarah Wroot

For a much more detailed description of the underlying botanical and biochemical processes in the growth of a grain of wheat see: