Sesamum
Family- Pedaliaceae
Scientific Name- Sesamum indicum L.
Common Name- Hindi- Til
Origin
- Sesamum along with coconut is regarded as the oldest oil yielding plant known to man. Widespread cultivation in Asia and Africa since ancient times has rendered it difficult to acertain the original home of sesame.
- It is cultivated extensively in India, Burma, Indo-China, China and Japan. It is also grown in the hotter and drier parts of Africa and the Mediterranean region. Cultivation of sesame is done in USA, Mexico and in some parts of Latin America as well.
Botany of the plant
- Annual or perennial, erect or procumbent herbs.
- Leaves – sessile or petiolate, entire, lobed or partite, often varying on the same plant.
- Flowers- solitary in the leaf axils, shortly pedicellate, calyx persistent or deciduous.
- Pedicels- usually short with necktarian glands at the base.
- Corolla foxglove like, obliquely campanulate.
- Ovary 2-celled, ovules numerous,
- Capsule oblong or sub-obconical, grooved, beaked at the apex.
- Seeds numerous and compressed.
Ecology
- Sesame prefers a light, well-drained soil which retains adequate moisture.
- Sesame flourishes in the tropical and subtropical regions, in the plains as well as up to an elevation of 1200 m. It is sensitive to low temperatures.
- During kharif season it is grown as a rain fed crop, if the rainfall does not fall below 50 cm. It is grown as a and irrigated crop in the rabi(winter) season.
Cultivation Practices
- In India sesame is sown alone, as well as a mixed crop.
- It is usually sown by a broadcast method with the seeds are mixed with sand or many out to facilitate sowing as the seed size is small. For broadcast sowing, the fields are opened up by shallow furrows and after the seed is scattered, a light harrow is used to cover up the seeds.
- Seeds germinate within 5-8 days. The crop comes to maturity in 100-140 days.
Harvesting
- The crop is harvested before the plants are completely dry because this prevents shattering of capsules.
- The proper time for harvesting is when the leaves turn yellow and start drooping but the capsules still look greenish.
- The plants are cut and piled in bundles for drying for about a week on the threshing floor. Threshing can be done easily by shaking the plants or by light beating on the floor or on a piece of cloth.
Uses
Sesame oil
- Sesame seed is rich in oil 50% and protein 20 to 25%.
- The oil can be extracted simply by pounding the seeds in a wooden mortar after which the oil is removed by floatation process with hot water. Direct solvent extraction methods are used for extracting the oil on a commercial basis. In India, sesame oil is used by using ghani which is drawn by bullocks or hydraulic presses.
- About 3/4 of the sesame oil produced in the country is used for edible purposes and the remaining is used for soap manufacture, paints, hydrogenation, perfumery, etc.
- Like other vegetable oils it is lacking in vitamin A and is rich in vitamin E. The most useful property of this oil is its high stability, so that unlike other fats, rancidity does not spoil flavour and destroy vitamins existing in other foods.
- It contains in addition to phytosterol and tocopherol, two compounds which are not found in any other oil, namely sesamin and scsamolin, which are responsible for the characteristic Baeudouin and Villavechia tests of sesame oil.
Baeudouin Test
When sesame oil is shaken with concentrated HCl, to which a little cane sugar has been added, it gives a characteristic red colour. This is known as the Baeudouin test. Villavecchia and Babris modified the Baeudouin test by replacing the cane sugar with furfural and the modified test is called Villavecchia test.
Sesame cake
Sesame cake (oil seed meal), obtained after extraction of oil, is rich in protein, calcium, phosphorus and the vitamin, niacin. It is fed to farm animals in combination with other oilseed cakes such as groundnut cake.
Sesame seeds are used in sweet meats. They are roasted and ground into meal and made into cakes. Sesame seed is also used by the bakery industry.
Diseases and Pests
Viral diseases
- Phyllody- Floral parts are transformed into green leafy structures.
- Leaf curl- The disease is characterised by severe downward curling of leaves and marked thickening of veins on the underside. The disease has been found to be graft-transmissible and spreads in nature through white-fly, Bemicia tabasi Gen.
Fungal diseases
- Leaf spot- Leaf spot or white spot of til is also known as blight of Sesamum, caused by Cercospora sesame and C. sesamicola.
- Phytophthora stem rot- Blackish lesions are formed on the collar of the stem at the soil level. Caused by Phytophthora parasitica.
- Anthracnose caused by Colletotrichum. spp. The affected portions of the plant become dark in colour. The disease affects the setting of the pods and in most cases the effective plans or destroyed before the pods mature.
- Fusarium wilt caused by Fusarium oxysporum var. sesame- Yellowing, drooping and withering of leaves. Discolouration of the wood occurs from the roots to the apex and ultimately leads to the death of the plant.
- Root and stem rot caused by two fungi Macrophomina phaseoli (Maubl.) and Rhizoctonia bataticola (Taub).
Bacterial diseases
- Bacterial blight- Caused by Xanthomonas spp.
- Bacterial black rot- caused by Pseudomonas sesami Malkoff.
Insect Pests
- The till leaf roller, Antigastra eatalaunalis Duponchal.
- The sesamum spinx, Acherontia styx Westwood.
- The sesame gall-fly, Asphondylia sesame F.
- Pod-sucking bugs, Aphanus sordidus F.
- Eusarcocoris ventralis W. Nysious inconspicuous D.
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