Sorghum bicolor



Sorghum bicolor

(L.) Moench 1794

pronounced: SAW-gum BY-kull-uh

(Poaceae — the grass family)


common name: sorghum

The word Sorghum is based on the Italian sorgo, a tall cereal grass; bicolor is Latin for ‘having two colours’.

Sorghum evolved in the steppes and savannahs of the north-east quadrant of Africa. It was domesticated there about 2000 BC, and spread throughout Africa, India, and later China. Grain sorghum has an amazing capacity to tolerate drought and heat, and is even able to produce grain during periods of extended drought, in circumstances that would impede production in most other grains. Its leaves roll along the midrib when moisture-stressed, and so present a smaller surface to the sun.

This is a cane-like grass, with leaves very similar to those of maize, and it grows up to about 2 m tall.

The flower head carries two types of flower: one type has no pedicel and has both male and female parts; the other has a pedicel, and is usually male.

The individual grains are about 3 – 4 mm in diameter. They vary in colour from pale yellow through reddish brown to dark brown, depending on the cultivar. Sorghum bicolor includes all cultivated sorghums as well as a group of semi-wild plants often regarded as weeds.

There is an enormous number of cultivars – well over 500. They cross readily without barriers of sterility or difference in genetic balance, and so it makes sense to group them into a single species. This makes the taxonomists’ work very difficult, but it is an advantage for the plant breeder, as he can manipulate the genetic make-up of this group to breed cultivars suitable to particular growing regions.

Sorghum bicolor is an important crop providing food and fodder in the semi-arid tropics. It is a staple food for more than 500 million people in more than 30 countries, although maize has to some extent replaced its use in southern Africa. It is used for the production of alcohol, especially beer. The whole plant is used for forage, hay and silage. The stem of some types is used for fencing, weaving, broom-making and firewood. Industrially it can be used for vegetable oil, waxes and dyes.

In Africa there are two basic types: white sorghum, which is sweeter and is used as a grain crop, and red sorghum, which is less tasty to eat, but is not so badly attacked by birds as it contains more tannin, which most birds find unpalatable; it also makes good beer.

In Queensland, there are strains of fodder sorghum that are used mainly for silage production, and a number of cultivars grown solely for grain. The fodder sorghums are also used for autumn grazing by dairy and beef cattle to fill in a feed shortage between summer and winter grazing crops. The grain sorghums are valuable for grazing after the grain has been harvested, and the crop residues (stubble, dropped seed-heads and regrowth, plus weeds) provide good autumn and winter roughage.

Among the Lepidoptera larvae that feed on sorghum are:

      • the Yellow Peach Moth Conogethes punctiferalis;
      • the Tomato Looper Chrysodeixis acuta;
      • the Cotton Web Spinner Achyra affinitalis;
      • the Common Swift Pelopidas agna;
      • the Orange Grass Dart Taractrocera anisomorpha; and
      • the Oriental Armyworm Mythimna separata.

Photographs taken 2010, Picnic Bay
Page last updated 6th April 2019