Tobacco

Morphology

Morphology and Growth

  • Common characters of subgenus rustica are : sturdy or more or less woody habit of growth; well defined petiolate. Cordate or semi cordate shaped and evenly spaced leaves.
  • The inflorescence is usually a compact 'thyrse' represented by a thickened central axis, shortened branches and a monopodial and sympodial development of peripheral flowers.
  • Tobaccco plant is a herbaceous annual. However, Nicotiana rustica is found sometimes to behave like a perennial. The plant height ranges from 90 to 240 cm in tabacum and 50 to 140 cm in rustica.

Tobacco Plant

  • The inter-nodes may be very short presenting a rosette appearance or even as long as 20-24cm.
  • The stems are usually round covered with glandular hairs with a tendency to produce branches near the base known as "Suckers".
  • The plants of rustica are more robust and densely growing than that of tabacum. If there are few leaves, the plant has an open appearance, but if they are numerous, the plants have a bushy appearance.

Leaves

  • The size of leaves may vary from 15 to 100 cm or even more in length. They may be narrow, long and drawn out like a whip, ellipitcal or broadly ovate with a marked variation even in the same plant.
  • The leaf angle varies from an upright to horizontal with dropping at the base, in the centre or at any point of the leaf.
  • The leaf base may be sessile or petiolate differing in the development of wings having a breadth of 5-6 cm. Sometimes in some sp. the auricles are also observed.
  • The lateral veins may be perpendicular to the midrib as in 'wrapper tobacco or may make acute angle with various intergrades as in 'Now'. The types to phyllotaxy normally observed are 1/3, 2/5, 3/8 and rarely 5/13.

Flowers

  • The tobacco has a terminal receme panicle which may be compact to very lax with a short or long peduncle. The inflorescence in main axis always flowers first and the side branches thereafter in order from top towards bottom.
  • The flowers are usually 5 cm in length and vary in their colour from pink, yellow, purplish, or white. The shape varies from funnel to flute.
  • The development of green colour differs in its intensity both inside and outside the Corolla tube. The corolla may be wheel shaped with acute apices to pentagonal shape and obtuse tips. Calyx is usually tubular but in few types leaf is globular and inflated.

Capsules

  • The capsules vary in size, shape and nature of apex, blunt or conical. The shape may be elliptical, ovoid or conical.

Seeds

  • Seeds are spherical or broadly elliptic with variation in degree of ridging on the seed coat. The colour varies from dark brown to light brown.

Common characteristics of subgenus tabacum are :

  • Woody semi-perennial
  • Erect members with evenly spaced leaves on definite internodes
  • Leaf shape ranges from broad ovate to linear or lanceolate
  • Sessile to petiolate conditions with varying degrees of wings and decurrent leaf base exist.
  • Inflorescence is less compact with short internodes and an open habit
  • Basal floral branches are usually long
  • Corolla is characterised by a wide throat, broad limb and usually light deep pink coloured.

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Taxonomy

Botanical Classification of Tobacco

  • The genus Nicotiana is one of the five large genera of Solanaceae and is represented by about the recognised species which are grouped into three sub groups.

  1. 1. Sub-genus : rustica
  2. 2. Sub-genus : tobacum
  3. 3. Sub-genus : petunoides

  • Out of the 65 species, only two species i.e. Nicotiana tabacum and Nicotiana rustica are cultivated extensively.
  • India grows both the species, but by far the largest area is under N. tabacum which is grown all over the country. Since N. rustica requires cooler climate, its cultivation is confined mainly to the northern and north eastern areas of the country i.e. Punjab, Uttar Pradesh, West Bengal, Bihar and Assam.
  • The N. tabacum varieties are known as desi types and have tall plants with broad leaves and have usually pink flowers.
  • Specific varieties of N. tabacum have been developed for Cigarette, Cigar, Cheroot, bidi, hookka and snuff tobaccos.
  • In addition to N. tabacum and N. rustica, which are commonly cultivated, many species of Nictoiana such as N. affinis are grown for ornamental purposes.
  • Some of the other species were used by Aboriginal (Red Indians and Australian natives) for chewing and smoking.

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Tamilnadu

Tobacco

Tobacco Management