Nicotiana rustica (PROSEA)
Introduction |
- Protologue: Sp. pl.: 180 (1753).
- Family: Solanaceae
- Chromosome number: 2n= 48
Synonyms
N. rugosa Miller (1768), N. asiatica Schultes (1809), N. humilis Link (1821).
Vernacular names
- Nicotine tobacco, tobacco, small tobacco (En). Tabac rustique, petit tabac (Fr)
- Indonesia: tembakau
- Malaysia: tembakau
- Vietnam: thuố lào.
Origin and geographic distribution
N. rustica is of South American origin but is only known from cultivation. It can sometimes be found in a semi-wild state in the Peruvian, Bolivian and Ecuadorian highlands. It was widely cultivated in Mexico, North America and on the Caribbean Islands in pre-Columbian times, and it was the first tobacco cultivated by Europeans in North America and Europe in the 16th Century. Later it was replaced by N. tabacum L. because this had a milder taste and flavour. N. rustica was also introduced in Asia, Africa, the Russian Federation, the Balkans and the Middle East, but has now lost its importance as tobacco producer in most countries.
Uses
Leaves of N. rustica are used for smoking, chewing or snuffing, because of their taste and flavour, but particularly because of the stimulating and mildly narcotic effects of the alkaloid nicotine. In Pakistan for instance, certain cigarette types may contain a blend of 40% N. rustica and 60% N. tabacum (Virginia) tobacco producing a very strong taste and flavour. Before the advent of synthetic insecticides (after 1945), N. rustica was also widely grown for nicotine extraction. Extracts from N. rustica leaves are sometimes applied in traditional medicine.
Production and international trade
Less than 3% of the present world tobacco production (6.6 million t) is estimated to come from N. rustica and very little of that reaches the international trade. In Pakistan about 25% of all tobacco produced is N. rustica . It is also of importance in northern India, Bangladesh, the Russian Federation and some North African countries.
Properties
Cured leaves of N. rustica contain: water 12-15%, protein 3-15%, carbohydrates 10%, sugar 3%, and ash up to 25%. Its nicotine content, 4-9.5%, is higher than that of N. tabacum , giving the smoke a much harsher taste.
The 1000-seed weight is 0.08 g.
Description
Erect, branched, annual herb, up to 1.8 m tall, bearing multicellular, viscid-glandular hairs. Root system extensive but rather superficial. Leaves alternate, 15-20 per plant, rather variable; petiole 5-6 cm long, not winged; blade ovate, elliptical or subcircular, 10-70 cm × 8-25 cm, base obtuse, margin somewhat undulate, apex acuminate, surface often rugose. Inflorescence a terminal, slender or compact panicle of monochasial or dichasial branches; pedicel 3-10 mm long; calyx tubular, 8-16 mm long, ending in 5 small, subtriangular, unequal lobes; corolla tubular, tube 10-18 mm long, widening above into 5 half-circular, green-yellow lobes 3-7 mm long; stamens 5, inserted near the base of the corolla tube and not exserting, 4 about equally long, 1 a little shorter; pistil with superior ovary, long style and 2-lobed stigma. Fruit an ovoid to globose capsule, about 7-17 mm long, enclosed by the calyx. Seed ellipsoid to ovoid, about 1 mm long, testa brownish and finely pitted. Seedling with epigeal germination.
Growth and development
Seeds of N. rustica require light for germination. Seedlings are ready for transplanting to the field 35-45 days after sowing, when they are 15-20 cm tall, with a rosette of 4-5 leaves. The root system is extensive but rather shallow and plants are susceptible to lodging under strong wind. Flowering starts 50-60 days after field planting. The anthers dehisce when the flower unfolds and at that time the stigma is also sticky and receptive. Self-pollination takes place normally, but nectar-collecting insects may cause 4-10% cross-pollination. The fruits are mature 3-4 weeks later.
The dormant axillary buds will only develop into lateral branches, called suckers, after topping or when the plant has lodged. Cultivated nicotine tobacco has an economic life span of about 4-5 months.
Other botanical information
N. rustica is thought to be an allotetraploid, and probably evolved from diploid N. undulata Ruiz & Pavon and N. paniculata L. Compared with N. tabacum , plants of N. rustica are generally shorter with much darker green, broader and thicker leaves. N. rustica is rather variable and numerous subclassifications exist, often mainly based on differences in leaf and inflorescence morphology. Because N. rustica is only known from cultivation, it seems more appropriate to classify the variability into cultivar groups and cultivars. No such classification exists, however. In Pakistan the two main groups of N. rustica are the dark "naswari" and the lighter "saffaid" or "white pattar". In northern India and Bangladesh, hookah (water pipe) cultivars are also grown.
Ecology
The climatic requirements of N. rustica are comparable to those of N. tabacum , though the former is more resistant to cold than the latter. N. rustica thrives on well drained and well aerated heavy soils.
Propagation and planting
Propagation of N. rustica is by seed (10 g/ha). Seed remains viable for over 10 years when stored dry and cool. There is no dormancy, except that freshly harvested seed should be allowed a post-ripening period of 3 weeks. It will then give 95% germination within 5 days after sowing. Seedlings are raised in seedbeds under shade. Seedlings should be thinned and hardened off by gradual removal of the shade, before transplanting to the field at a density of about 20 000-25 000 plants/ha.
Husbandry
N. rustica fields are regularly hoed to remove weeds and improve soil aeration. For high yields and heavy broad leaves the crop needs appropriate soils, heavy manuring and large nitrogen dressings. Recommendations for N. rustica in North Bengal include 10 t/ha of manure and 112 kg/ha of N fertilizer. In Pakistan, "white pattar" is given an average application of 168 kg N, 90 kg P and 90 kg K per ha, whereas "naswari" receives a large dose of manure plus 224 kg N, 200 kg P and 112 kg K per ha. Tobacco should be grown on the same land for no more than 2 years in succession, to check the incidence of diseases and pests (e.g. bacterial wilt and root-knot nematodes).
Diseases and pests
N. rustica is subject to the same diseases and pests as N. tabacum . They include: seedling damping-off ( Pythium spp., Rhizoctonia solani ), bacterial wilt ( Pseudomonas solanacearum ), black shank ( Phytophthora nicotianae ), frog-eye on leaves ( Cercospora nicotianae ), virus diseases like tobacco mosaic virus (TMV), cucumber mosaic virus (CMV), tobacco leaf curl virus (TLCV) and tobacco etch virus (TEV), root-knot nematodes ( Meloidogyne spp.), aphids ( Myzus persicae ), whiteflies ( Bemisia tabaci ), thrips ( Thrips tabaci ), leafworms ( Spodoptera litura ) and budworms ( Helicoverpa spp.).
Harvesting
Most N. rustica is stalk-cut at 100-130 days after planting. Only the hookah cultivars in India are primed (harvesting of individual leaves).
Yield
It should be possible to obtain 1.5-2 t/ha of cured leaves of N. rustica .
Handling after harvest
In Pakistan harvested plants of "white pattar" or "saffaid" are sun cured for about two weeks and turned once or twice to obtain a relatively light-coloured leaf. Harvested "naswari" plants are left in the field for about six days to dry partially, before being gathered into heaps, which will be turned several times in the ensuing 1-2 months in a combined curing and fermentation process. The aim here is a dark, strong-smelling, rather thin tobacco. In Algeria harvested plants are wilted for a short period in the field and then air cured under roofed but open structures, often under lean-to roofs against houses or other buildings.
Genetic resources and breeding
Germplasm collections of N. rustica are available in the main production centres. N. rustica is polymorphic with genetic variation present in numerous locally selected cultivars. In East Africa and the Russian Federation, selection efforts used to focus on increased nicotine content (up to 14%), but at present there is no longer any interest in the commercial production of nicotine as an insecticide.
Prospects
The importance of N. rustica as a supplier of tobacco leaves for smoking is likely to decrease, since the rather harsh taste and flavour are not much appreciated beyond traditional users. However, it could be revived as a source of nicotine if interest in natural insecticides were to revive. For South-East Asia, interest in N. rustica will remain marginal.
Literature
- Akehurst, B.C., 1981. Tobacco. 2nd edition. Tropical Agriculture Series. Longman, London, United Kingdom. 764 pp.
- Danert, S., 1963. Zur Systematik von Nicotiana rustica L. [On the taxonomy of Nicotiana rustica L.]. Die Kulturpflanze 11: 535-562.
- Garner, W.W., 1951. The production of tobacco. McGraw-Hill, New York, United States. 516 pp.
- Gerstel, D.Uy. & Sisson, V.A., 1995. Tobacco. In: Smartt, J. & Simmonds, N.W. (Editors): Evolution of crop plants. 2nd edition. Longman Scientific & Technical, Harlow, United Kingdom. pp. 458-463.
- Lucas, G.B., 1975. Diseases of tobacco. 3rd edition. Biological Consulting Associates, Raleigh, North Carolina, United States. 621 pp.
- Purseglove, J.W., 1968. Tropical crops. Dicotyledons 2. Longmans, London, United Kingdom. pp. 539-540.
Authors
B.I. Utomo W. & E. Rahayu