San: Lasunah, Rasonah;
Tam: Vellaipuntu; Mar: Lasunas; Ass: Naharu; Tel:Vellulli, Tella-gadda;
Importance: Garlic is one of the important bulb crops used as a spice or condiment with medicinal value throughout the world. It possesses high nutritive value. Its preparations are useful in vitiated conditions of kapha and vata, cough, whooping cough, bronchitis, asthma, fever, facial paralysis, flatulence, colic, constipation, atonic dyspepsia, helminthiasis, duodenal ulcers, pulmonary and laryngeal tuberculosis, opthalmopathy, cardiopathy, fatigue, leucoderma, leprosy, hysteria, haemorrhoids, sciatica, otalgia, lumbago, swellings, splenopathy, hepatopathy, pneumonopathy, anthralgia, sore eyes, ear ache and dental caries (Kumar et al, 1997).
Distribution: Garlic is a native of Southern Europe and it is cultivated all over the world.. It is grown throughout India; Gujarat and Orissa being the leading states.
Botany: The genus Allium of Liliaceae family comprises a number of species. The important ones are the following:
A. sativum Linn. syn. A. porrum Linn.
A. cepa Linn.
A. ampeloprasum Linn.
A. ascalonicum Linn. A. leptophyllum Wall. A. macleanii Baker.
A. schoenoprasum Linn.
A. tuberosum Roxb.
Allium sativum is a scapigerous foetid perennial medicinal herb with underground compound bulbs covered over by outer white thin scales and with simple smooth, round stem, surrounded at the bottom by tubular leaf sheath. The leaves are simple, long, flat and linear. The flowers are small and white arranged in rounded umbels mixed with small bulbils. The entire umbel is enclosed in a tear-drop-shaped membranous spathe. Flowers are usually sterile (Warrier et al, 1993).
Agrotechnology: Garlic can be grown under a wide range of climatic conditions. It prefers moderate temperature in summer as well as in winter. Short days are very favourable for the formation of bulbs. Garlic requires well drained loamy soils rich in humus, with fairly good content of potash. Garlic is propagated by cloves or bulblets. In the hills, sowing is done in April and May. Types with bold and compact cloves and thick white covering sheath are preferred for planting. Ootty-1 garlic is an improved variety by clonal selection released from TNAU, Coimbatore. Garlic may be broadcast, planted in furrows or dibbled at the rate of 150-200kg cloves/ha. In furrow planting, cloves are dropped 7.5-10cm apart in furrows 15cm deep and covered lightly with loose soil. Cloves may be dibbled 5 to 7.5cm deep and 7.5cm apart in rows which are 15cm apart with their growing end upwards and then covered with loose soil. A basal dose of 60kg N and 50kg each of P2O5 and K2O are applied along with 25t/ha of FYM. 60kg N is given as topdressing 45 days after planting. First irrigation is given immediately after sowing and subsequent irrigations are given at 10-15 days interval depending upon the soil moisture availability. The last irrigation should be given 2-3 days before harvesting to facilitate easy harvest and minimum damage to bulbs. First weeding and hoeing is to be done at one mo nth after sowing followed by a second weeding one month after first interculture. Hoeing at about two and a half months from sowing loosens the soil and helps in setting of bigger and well-filled bulbs. Garlic is attacked by Thrips tabacii which causes withering of leaves. Application of methyl demeton 25EC or dimethoate 30EC at 1ml/l will check the pest incidence. Leaf spot caused by Alternaria solanii can be controlled by spraying Dithane M.45 at fortnightly intervals at 2.5g/l of water. Garlic is harvested when the tops turn yellowish or brownish and show signs of drying up. The plants are uprooted, tied into small bundles and kept in shade for 2-3 days for curing. Average yield of garlic is 6-8t/ha. (Kumar et al, 1997.)
Properties and activity: Garlic bulb is reported to contain volatile oil, alliin (S-allyl-L-cysteine sulfoxide), S-methyl-L-cysteine sulfoxide and allinase. It is rich in vitamins like thiamine, riboflavine and niacin. Volatile oil contains allicin (diallyl thiosulphinate), an active odour principle of garlic. Other major compounds present are diallyl disulphide, diallyl trisulphide, allyl methyl trisulphide and allyl methyl disulphide (Husain et al., 1992).
Garlic bulb is antirheumatic, stimulant, diaphoretic, expectorant, diuretic, antispasmodic, astringent, antiparalytic, antileprotic, aperient, febrifuge, carminative, stomachic, alterative and emmenagogue. The essential oil is hypocholestrolemic, hypotensive, antitumour and antidiabetic. Diallyl disulphide and diallyl trisulphide from essential oil have larvicidal action. Bulbs also have anti-bacterial, and anti-fungal activity.