The guar bean or cluster bean (Cyamopsis tetragonolobus), an annual legume, is the source of guar gum. It grows best under conditions with frequent rainfall, but tolerates arid conditions well. 80% of world production is in India, but due to strong demand, it is being introduced into new areas.
For best growth, the guar bean requires full sunshine, flashing rainfalls that are moderately frequent, and well drained soil. However, it is extremely drought tolerant and thrives in semi-arid regions. Too much precipitation can cause the plant to become more "leafy" thereby reducing the number of pods and/or the number of seeds per pod that affects the size and yield of seeds. The crop is sown after the first rains in July and harvested in late October. It is grown principally in northwestern India, and Pakistan with smaller crops grown in the semi-arid areas of the high plains of Texas in the USA, Australia and Africa. The most important growing area centres on Jodhpur in Rajasthan, India.
Currently India is the source of about 80% of the world production of guar gum. Several commercial growers have converted their crops to guar production to support the increasing demand for guar and other organic crops in the United States.
Varieties: Pusa Naubahar and Pusa Sadabahar. Seeds at the rate of 10 to 12 kilograms/hectares (9–11 lb/acre) are planted at a spacing of 45-60 x 20-30 cm (18–24 x 8–12 in) in February-March and June-July. During rainy season, the seeds are sown 2-3 cm (~1 in) deep on ridges and in furrows during summer months. FYM is applied at the rate of 25 tonnes/ha (11.1 tons/acre). N, P2O5 and K2O recommendation for the crop is 20:60:80 kg/ha (18:53:71 lb/acre). Average yield is 5 to 6 tonnes/ha (2.2–2.6 tons/acre).
Guar can be eaten as a green bean, but is more important as the source of guar gum. Guar beans have a large endosperm that contains galactomannan gum, a substance which forms a gel in water. This is commonly known as guar gum and is used in dairy products like ice cream and as a stabilizer in cheese and cold-meat processing.
Another use is as a fiber supplement. After being partially hydrolyzed, guar gum is completely soluble in water and soft food. Being approximately 75% dietary fiber, it allows fiber to be added to a food with a minimal effect on taste and texture.
Derivatives of Guar gum that has been further reacted is also used in industrial applications such as the paper and textile industry, ore flotation, the manufacture of explosives and hydraulic fracturing of oil and gas formations. Guar gum has also proven a useful substitute for locust bean gum (made from carob seeds).