What is "guar"

n. An annual legume ((taxlink Cyamopsis tetragonolobus species noshow=1)), used as a food for cattle and humans.

n. drought-tolerant herb grown for forage and for its seed which yield a gum used as a thickening agent or sizing material [syn: cluster bean, Cyamopsis tetragonolobus, Cyamopsis psoraloides]

The Guar or cluster bean, with the botanical name Cyamopsis tetragonoloba, is an annual legume and the source of guar gum. It is also known as Gavar, Guwar or Guvar bean.

The origin of Cyamopsis tetragonoloba is unknown, since it has never been found in the wild. It is assumed to have developed from the African species Cyamopsis senegalensis. It was further domesticated in India and Pakistan, where it has been cultivated for many centuries. Guar grows well in semiarid areas, but frequent rainfall is necessary.

This legume is a very valuable plant within a crop rotation cycle, as it lives in symbiosis with nitrogen-fixing bacteria. In fact, agriculturists in semi-arid regions of Rajasthan follow crop-rotation and use guar as a source to replenish the soil with essential fertilizers and nitrogen fixation, before the next crop. Guar as a plant has a multitude of different functions for human and animal nutrition but its gelling-agent-containing seeds (guar gum) are today the most important use. Demand is rising rapidly due to industrial use of guar gum in hydraulic fracturing ( oil shale gas). About 80% of world production occurs in India and Pakistan, but due to strong demand, the plant is being introduced into new areas.