Changes

*Guar, cluster bean, Siam bean (En). *Cyamopse à quatre ailes (Fr)*Malaysia: kottavarai (Malayalam, Tamil). *Burma (Myanmar): pè-walee, walee-pè

*A robust, bushy, erect, annual herb, 20-100 cm tall in improved cultivars, up to 3 m in landraces. Root system well developed laterally. *Stems and branches angular, grooved, appressed pubescent with white, forked hairs, sometimes glaucous; some cultivars remain unbranched. *Leaves alternate, trifoliolate; leaflets elliptical to ovate, terminal one 8-12 cm long, lateral ones 5-8 cm long; rachis 3-7 cm long, pulvinate; margins toothed, the length of the teeth less than 1/10 of the breadth of the leaflet, which usually exceeds 1 cm. *Inflorescence a dense, axillary raceme with 5-30 flowers; flowers .*Flowers up to 9 mm long; calyx hairy, ending in 5 unequal teeth, carinal tooth longest; petals creamy white on emergence, changing through pink to light purple, standard orbicular, wings and keel oblong; stamens 10, filaments united into a staminal tube, anthers apiculate. *Pod 6-12-seeded, 4-12 cm long, in stiff erect clusters, pubescent or glabrous, straight to slightly curved, beaked, with a single ridge at one suture and two ridges at the other. *Seed hard, flinty, flattened, ovoid, about 5 mm long, white, grey or black. *Seedling with epigeal germination.

''Cyamopsis'' DC. is a small genus of 3 species and is closely related to the genus ''Indigofera'' L. All species have a diploid chromosome number of 14. The 2 wild species are African ( ''C. serrata'' Schinz) or mainly African ( ''C. senegalensis'' ).

Numerous cultivars of guar have been developed. In general, branched types are more suitable for seed production, while erect, single-stem types that produce larger and more fleshy pods are preferred in vegetable production. In India three main types are sometimes recognized: "Deshi", a mostly rainfed seed crop, 1.2-1.5 m tall; "Pardeshi", mainly grown for green pods, 1.5-1.8 m tall; and "Sotiaguvar", mostly grown for fodder and green manure, 2.5-3.5 m tall. "Sofia" is a multipurpose cultivar from Gujarat, grown as a green manure and shade plant and for its green pods, "Durgapura Safed" is a successful cultivar for forage and grain production. "Brooks" was the first cultivar released in the United States, moderately resistant to the main diseases ( ''Alternaria'' leaf spot and bacterial blight). However, its resistance to bacterial blight tends to break down under heavy infestation, as is the case with "Kinman" released in 1974. "Mills" (early maturing), "Esser" (late maturing) and "Hall" (full season) were released in between 1965 and 1975, "Lewis" (intermediate) and "Santa Cruz" (full season) in 1985. These are all higher yielding than older cultivars and were more resistant to bacterial blight when released.

Internationally, bacterial blight, caused by ''Xanthomonas cyamopsidis'' and leaf spot caused by the fungus ''Alternaria cucumerina'' var. ''cyamopsidis'' are the main diseases of guar. Bacterial blight is seed-borne and infected seedlings are often killed rapidly. In older plants the disease develops from transparent, oily leaf spots coalescing into brown, angular, necrotic lesions. Infection spreads systemically throughout the plant and can kill it at any stage of development. The cultivars "Brooks", "Hall", and "Mills", which were originally resistant, are now affected by a highly virulent strain. Soaking the seed in hot water at 56 °C for 10 minutes will eliminate seed-borne infection. ''Alternaria'' leaf spot develops between flowering and pod set. It causes defoliation, especially during periods of high rainfall and humidity. Dithane and cupramar give excellent control of this disease. A mildew, caused by ''Oidiopsis taurica'' , is widespread and causes some damage, especially during periods of humid weather.

Guar is relatively free of pests. The midge ''Contarinia texana'' causes damage in the United States and has caused yield losses of 20-30%. Effective, economical chemical control is possible. A gall midge ( ''Asphondilia'' sp.) occurs in India and the United States and may cause limited damage late in the growing season.