Cluster bean/guar (Cyamopsis tetragonoloba) is a multi-purpose crop. The Guar plant produces a cluster of flowers, therefore, it is also known as cluster bean. Its green pods are used as vegetables, grains as pulse and for gum extraction, and as a green manure crop in agriculture. Since it is a leguminous crop, it also has soil-enriching and erosion-resisting properties. The tender pod of grain type varieties is also used extensively as a vegetable (fresh and dehydrated) in spite of its poor quality and is the most common poor man’s vegetable of desert dwellers. Guar leaves can be used like spinach and the pods are prepared like salad or vegetables. Guar is an annual plant generally grown in dry regions of India. Cluster beans, tender pods are extremely popular veggies, they are indigenous to India and can be obtained all year round generally in most marketplaces. Cluster beans/guar pods are rich in soluble dietary fiber. Guar contains vitamin C, K, A, and manganese, potassium, folate, iron. It is also a good source of fiber. As a rich source of protein and fiber, cluster beans have several health benefits in both vegetable and powder form (guar gum).
In India, it is grown in Rajasthan, Gujarat, Haryana, Punjab, Uttar Pradesh, Madhya Pradesh, and Odisha. Its taproot system is well developed. Therefore, it is also popular as drought hardy plant and can survive better under comparatively dry conditions.
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Climate and soil
Guar is a photosensitive crop. It grows in specific climatic conditions, which ensures a soil temperature around 25°C for proper germination, long photoperiod, with humid air during its growth period, and finally short photoperiod with cool dry air at flowering and pod formation. It is grown during the spring-summer and rainy season for green pods, used as vegetables. It is definitely a Kharif crop for grain purposes in North India, but some varieties have been found to grow during March to June as spring-summer crops and other varieties grow during July to November as rainy season crops under South Indian climatic conditions. For best growth, the guar bean requires full sunshine, flashing rainfalls that are moderately frequent, and well-drained soil. It is a crop preferring a warm climate and grows well in the subtropics during summer. It also grows well in the arid zone with 30 to 40 cm of rainfall. However, it is extremely drought-tolerant and thrives in semi-arid regions. Heavy rains, producing waterlogged conditions or more compact soils disturb its root system with surface feeding nature and reduce nitrogen-fixing bacterial activity. Waterlogging adversely affects both growth and productivity and a warm climate is suitable for cultivation.
Cluster bean can be grown on almost all types of soil, well-drained sandy loam soil with a pH range of 7.5 to 8.0 is preferred. This crop can tolerate salinity. Heavy clay soils, poor in nodulation and bacterial activities, are not suitable.
A brief description of the improved varieties of vegetable cluster beans is given here.
Durga Bahar: It is a photo-insensitive variety and can be grown in both the summer and rainy seasons for a vegetable purpose. The plants are glabrous, unbranched bearing white flowers. Clusters of long fleshy pods are borne at each node of the stem. The first picking of green pods may be obtained in 45 to 50 days after seed sowing. The green pod yield of this variety is 7-7.5 tonnes/ha.
Kanchan Bahar (M 83): This photo-insensitive vegetable type variety, can be grown in both the spring-summer and rainy seasons. This variety is unbranched, tall (125-150 cm); indeterminate growth habit; fast-growing and luxuriant, white flower; fleshy, glabrous, and long pods; green pod yield is 7.5-10 tonnes/ha. Moderately resistant to insects, powdery mildew, root rot, etc.
Pusa Mausami: It is recommended for vegetable pod production in Punjab, Haryana, Delhi, and Uttar Pradesh.
Its plants are unbranched, produce slender, attractive, smooth long pods. The pods being non-fibrous are used as vegetables. The first plucking of pods begins 80 days after sowing. This variety can be grown under rainfed as well as irrigated conditions. Its green pod yield is 5-6 tonnes/ha.
Pusa Navbahar: This variety has wide adaptability and can be grown throughout India during the rainy season. It is especially popular for longer and better-quality pods in South India. Its plants are unbranched and produce clusters of pods at each node. Its pods are non-fibrous. It has a prolonged period of plucking and green pod yield is 6-7 tonnes/ha.
Pusa Sadabahar: This variety is suitable for green pod production. It is photo-insensitive and grows. for longer duration producing green pods for pretty sufficient period. It can be sown as early as March and starts producing pods after 45 days of sowing, plucking of pods continues till September. It is also suitable for green fodder and green manuring. Its green pod’s yield is about 6-7 tonnes/ha.
Thar Bhadavi: This variety is suitable for vegetable uses under hot arid agro-climatic conditions. The thin and medium-long pods start 55 days after sowing as a rainfed crop. The plants can attain a height of 75 150 cm and the average green pod yield potential is 6.5-12.5 tonnes/ha under varying situations of crop production.
Guar crop requires a well-prepared field, with adequate soil moisture for its seed germination. During the early growth period, soil aeration encourages root development and bacterial growth. Therefore, the field should be ploughed to a fine tilth by giving two or three deep ploughings with soil-turning plough, followed by harrowing and planking. The field should be free from weeds and other crop residues. Arrangements for drainage-channel-cum-water channels for heavy rainfall areas or irrigated areas should be made while preparing the field. The farmyard manure should be mixed with soil at the time of the last ploughing.
In South India, it is sown at any time between February and October. Guar sowing time is adjusted from May to June to increase the supply of vegetable pods. Crop sown in June in Haryana and July in Punjab gives better production of vegetable pods. The seed rate of guar crop varies from 15 to 45 kg/ha depending upon variety, crop purpose, soil moisture, and spacing. About 15 to 18 kg/ha seed is sufficient for grain and vegetable crops.
Method of sowing
Wider spacing of 60 cm x 30 cm is desirable for crops grown for green pod production. A spacing of 45 cm x 15 cm between rows and plants is given for crops grown for grain production. Line sowing is also useful for carrying out hoeing-weeding and removing excessive rainwater.
Manures and fertilizers
Guar needs 10 12 tonnes/ha of well-decomposed farmyard manure, especially when it is being cultivated on poor sandy soils. It is applied a month before sowing. Phosphatic fertilizers about 60 kg, potassic 20 kg/ha along with 20 kg of nitrogen are applied as basal dose at the sowing, just 4 to 5 cm below the seed. Twenty-five kg nitrogen/ha is applied as a top dressing after 30 days of sowing.
Irrigate the field immediately after sowing and then at weekly intervals. Rainy season crop does not require any additional irrigation if rains are well distributed but summer crops may require additional irrigation. If rains are too heavy, the excess water should be drained off promptly. For dry season crops, irrigation at fortnightly intervals in the early summer and at ten days intervals, later on, should be given. Normally, the crop requires 4-5 irrigations.
Guar field in Kharif is always full of a number of weed plants. Well and early prepared seedbeds help reduce weed pressure. Hoeing and weeding in the initial stages of plant growth reduces the weed-crop competition and increase soil aeration for bacterial growth. The application of Basalin @ 1 kg a.i./ha as a pre-planting dose suppresses the growth of grasses and other weeds.
Diseases and pests
The most common diseases of guar are wilt, bacterial blight, powdery mildew, and anthracnose.
Wilt: This disease is caused by Fusarium moniliforme. The pathogen is soil-borne, therefore, its damage is of localized nature. It causes infection to the base of plants including roots and seedlings. The roots show dis-coloration and plant wilts. Poor emergence of seedlings is the first symptom of the disease, the seedlings rot before or soon after emergence. Mixed cropping and soil application of bio-agent Trichoderma is most effective in reducing root rot incidence.
Anthracnose: This disease is caused by Colletotrichum capsici. The disease is more severe in high rainfall areas. The fungus is seed-borne and symptoms appear in the seedling stage. The symptoms of the disease are black, sunken, crater-like cankers on the pods, stem, or cotyledons. The lesions remain isolated by yellow-orange margins. They give out a dull salmon color ooze from the center when humidity is very high. For control use healthy seed, avoid excess watering, give wider spacing and use hot water treated seed.
Powdery mildew: White powdery growth occurs on leaves, spreading to cover the stem and other plant parts. In severe cases, the entire plant dries up. Warm temperature (33° C and above), low humidity (below 75%), and bright sunlight are congenial for the development of disease.
Bacterial blight: This disease is caused by Xanthomonas cyamophagus. The disease is characterized by irregular, sunken, red to brown leaf spots surrounded by a narrow yellowish halo. Several spots coalesce to form irregular patches. The spots may also develop on pods.
Leaf spot: This disease is caused by Myrothecium roridum. Dark brown round spots appear on a leaf. In case of severe infection, several spots merge together and leaflets become chlorotic and usually drop off. If plants are infected in the early stages of growth, there may not be any flowering.
Guar is a rainy season crop. Therefore, a number of insect pests feed and grow on its leaves and pods. Some important ones are described here.
Hairy caterpillar: It is a polyphagous pest and causes heavy damage during Kharif. The adults lay eggs in clusters over the surface of the leaves. The larvae cause characteristic skeletonization of leaves during the early gregarious stage and later they completely defoliate the plant. The pest can easily be controlled by the mass trapping of adults in light traps during the night. It has been highly effective.
Jassid: It is a serious pest of the crop. The nymph is wingless and found in abundance on the lower surface of the leaves and sucks the cell sap. Leaves become yellow at the margin.
Leafhopper, aphids, and whitefly: These are minor pests.
Harvesting and post-harvest management
Tendergreen pods are used as a vegetable and in the southern part of India, they are dehydrated and stored for future use. The pods of the guar become ready for plucking, depending upon the variety, from 40 days onwards after sowing. Picking is done at an interval of 10-12 days. The tender pods are harvested by cutting or twisting. The pods should be picked with care to avoid injury to the plant. Green pod yield is 5-7 tonnes/ha in 90 days of crop duration.
When the crop is grown for seeds, it is left until the pods are mature, then harvested with the help of sickles and dried and threshed. A good guar crop of the vegetable type under favorable climatic conditions yields 1.0-1.5 tonnes/ha of dry seeds.