5.5 Guar (Cluster Bean). GUAR: forgotten crop growing in most marginal conditions many modern applications.

5.5Guar (Cluster Bean)

GUAR:forgotten cropgrowing in most marginal conditionsmany modern applications

Guar - Introduction Guar is a drought tolerant annual legume that grows in

hot, semiarid regions with sandy soils

The major world suppliers are India, Pakistan, the United States and smaller acreages in Australia and Africa

The world demand for Guar increased

which lead to introduction of Guar in

other countries

Guar - Crop properties Guar is an upright course-growing summer annual legume

(18-40 inches) (45-100 cm)

The deep roots reach deep moisture

Leaves, stem and pods are smooth

The Guar bean has a large

endosperm

The endosperm contains large

amounts of gum which is the

marketable product of the plant

Guar – Some examples of use

The gum of Guar forms hydrates rapidly in water into a

viscous gel and is therefore used in various products

In Asia: Beans for vegetable consumption Crop for cattle feed As green manure

In the United States: No calorie binding agent

• fi stiffener in soft ice cream In pharmaceutical industry In cloth and paper manufacture Oil well drilling muds

Guar – climate and soil Drought resistant High toleration of temperature (77 to 95˚F) (25 to 35˚C) Grows well under a wide range of soil conditions, but

preferably fertile, medium textured and sandy loam soils Salinity and alkalinity tolerant Soil improving crop Fits in crop rotation program (with grain sorghum, small

grains or vegetables)

Cultivation - Seed preparation Select seeds with same size and colour Selected seed must be free from other crop and weed

seed Select seed from the most recent varieties (New varieties

are more resistant to diseases) Inoculate the seed before planting with a special guar

inoculant (or a cowpea inoculant) Plant the seeds in moist soil within 2 hours after

inoculation The seed bed should be free of weed

Cultivation – Seeding date Plant Guar when soil temperature is over

70˚F (21°C) Optimum temperature for germination is

86˚F (30°C) Essential conditions:

Warm seedbed Adequate soil moisture Warm growing weather

Cultivation – Seeding and fertility With row crop planter, Guar can be planted in rows

from 36 to 40 inches. (90-100 cm) Planting depth of 1 to 1.5 inches deep (2.5-4 cm) Guar requires a high level of phosphorous (22 to

34 kg of P2O5/ha) and a medium level of potash (45 to 56 lb of K2O/ha)

Apply fertilizer before planting and below the seed Optimum pH value is between pH 7 an pH 8

Guar varieties in USA Brooks; (1964); first improved variety. High yielding and

resistant to major diseases. Hall; later maturing compared to Brooks. Resistant to

bacterial blight and Alternaria leaf spot. Best adapted to heavier soil types and higher elevation.

Mills; Early maturing and also resistant to bacterial blight and Alternaria leaf spot. Lower yields than Hall and Brooks.

Kinman; (1975) a week earlier in maturity than Hall. Highly resistant to bacterial blight and Alternaria leaf spot.

Esser; (1975) medium to late in maturity. Better disease tolerance than Brooks.

Lewis: (1986) Medium to late maturing. Seed yields are approximately 25% higher than Kinman.

Control MeasuresWeed controlBecause of the slow growing rate of young Guar plant, weed control is important Mechanical control:

Do not seed Guar in fields with Johnson grass and other perennial weeds

Early land preparation minimizes weed problems Chemical control:

Treflan (selective herbicide) can be used to control annual grasses and annual broadleaf weeds

Diseases control Select disease-resistant varieties and high quality certified seed to

prevent Guar from Alternaria leaf spot (fungal disease) and Bacterial blight (seed-borne disease causing plant losses)

Control of insects and other predators Guar Midge is the primary insect pest in the Southwest of the USA.

Rainfall or sprinkler irrigation may reduce the midge population

Harvesting

Seed pods are brown and dry at maturity To speed up drying and to kill weeds, Gramoxone

(paraquat) can be used Guar beans can be harvested with a normal grain

combine To clean out foreign materials use a high fan speed Reels should be set deep enough in the Guar to

control stalks (15 to 30 cm ahead of the cutterbar) For hay: cut crop when first pods turn brown For green manure: Guar should be turned under when

lower pods turn brown For seeds: after harvesting Guar can be used as

mulch when it is plowed under

After harvesting

Income and production costs vary every year and are also

depending on soil types Yields vary from 55 to 360 kg per hectare Production costs are between 8 and 16 USD/hectare.

(depends on fertilizer usage and other production practices

Situation in Pakistan

Guar is poor man’s crop Only a few guar gum processing plants – that

are struggling to survive Quality issues Guar processing needs revival and

international marketing effort!

Sources of Pictures

Sheet 1 – www.niemagazine.com Sheet 2 - www.plthomas.com/guar.html Sheet 3 - juniper.tamu.edu/Agronomy/guar_pods.htm Sheet 4 - http://www.shreevinayakcorp.com/guar-gum.html Sheet 8 - http://www.guar-tex.com/images/seed.jpg Sheet 12 - http://milksci.unizar.es/bioquimica/temas/azucares/

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