Cane sugar is currently grown primarily in tropical regions. The highest latitudes at which cane is grown is in Natal, Argentina and at the southern extremes of the Australian industry (approximately 30 degrees S), and at 34 degrees N in northwest Pakistan, and 37 degrees N in southern Spain (Jenkins 1966).
The first New World sugar cane mill began grinding in about 1516 in the Dominican Republic. Sugar production spread to Cuba, Jamaica, Puerto Rico, and the other Greater Antilles by the end of the 1500's (Hagelberg 1985).
Fungal diseases such as red rot (Colletotrichum falcatum Went), root rot (Pythium graminicolum Subr.), pineapple disease (Thielaviopsis parodoxa (de Seynes) C. Moreau), downy mildew (Sclerospora sacchari Miy), and smut (Ustilago scitaminea Syd.) can also cause damage. Red rot causes the setts to be seriously damaged at low temperatures. Root rot was responsible for the failure of "Otaheite" (a noble cane) in Mauritius in 1846 and several other areas later. Pineapple disease attacks the setts causing the center to turn black and smell like overripe pineapples. Downy mildew is currently only found in the western Pacific and was responsible for severe losses in Queensland until rigorous controls were initiated. Smut causes black whiplike organs to emerge from the center of the leaf-roll and is important in southeastern Asia and South Africa (Purseglove 1979).
Mosaic is a viral disease, whose vectors include Aphis maidis Fitch, was first recognized in Java in 1892 and causes severe stunting in some cases. other viral diseases include ratoon stunting, chlorotic streak, Fiji disease, and Sereh disease (Purseglove 1979). The most destructive insects of sugar cane are stem-borers, the larvae of several genera of moths. The larvae burrow into the stem and on emergence cause loss of sucrose and weakened stems. Biological control, the use of natural parasites, is the most effective control for these (Purseglove 1979). Other pests include termites in India and white grubs in Queensland. Rats are also a problem in many areas, for they eat the cane and introduce pathogens. The Indian mongoose, Herpestes, was introduced in the West Indies around 1870. This was a failure because they found they were able to catch birds easier (Purseglove 1979).
The goal of cane breeding is to produce an economic yield of sugar sustained over several ratoons. Sugar canes are highly polyploid, wind pollinated outbreeders. They are clonally propagated, highly heterozygous, and intolerant to inbreeding. New varieties are sought from the first generation progeny of crosses between clones. There are five species of interest to cane breeders. S. officinarum (2n=80) has good sugar quality and low fiber, although it is susceptible to most of the main diseases, except gumming disease and smut. S. spontaneum (2n=40-128) is a source of resistance to many diseases, including "Sereh", mosaic, gumming, red rot, and downy mildew. S. barberi (2n=82-124) are considered the most important breeding canes and are immune to gumming and mosaic and resistant to downy mildew, but susceptible to smut and red rot. S. sinense (2n=82-124) is difficult to breed, but has given rise to some useful breeding lines. S. robustum (2n=60-194) has been used to some extent in breeding lines (Wrigley 1982).
Breeding and selection of cane is not a simple process since viable seeds are seldom produced. Breeding occurs at the experiment stations which are able to provide the proper conditions and techniques required. The setts of new varieties are then distributed to the cane growers. Through selective breeding the yield has been increased by 85%.
Today, sugar cane has many industrial uses and is one of the most widely used and cheapest domestic products (Jenkins 1966). In sugar factories the harvested cane is shredded and crushed with heavy rollers to retrieve the juice which contains 10-20% sucrose. The pH is raised with lime and the mixture is heated to around 100 degrees C for several hours. The lime causes suspended materials, proteins, waxes, and fats to precipitate. Further impurities are allowed to settle in large containers and are removed from the bottom. This residue is known as filter cake or filter mud. The clear juice is again heated in a series of evaporators to form crystals and separated from the molasses in centrifuges. About 1 ton of raw sugar can be extracted from 8-9 tons of cane (McIlroy 1963). This raw brown sugar can be further refined to produce white sugar (Heiser 1981). Sugar cane has many other uses besides the production of sugars. Molasses is a by-product of the manufacturing of cane sugar. It is a residual syrup from which no more crystalline sucrose can be obtained by simple techniques. Approximately 2.7% of a ton of cane can be extracted as molasses. In 1980 nearly 30.8 million tons of molasses were produced, with Brazil leading production with about 5.2 million tons (Paturau 1982). The uses of molasses are many. Starting around 1850 it was often used as a fertilizer for cane soils, however this use is negligible today. Its use as a stockfeed can be dated back to at least 1811 in Germany. Today, at least 600,000 tons are used annually in the U.S. alone. Its most important feed characteristic is its high carbohydrate contents (Paturau 1982).
Molasses can also be distilled and fermented to produce various items. Molasses, along with cane juice and other by-products can be fermented to produce an alcoholic distillate, otherwise known as rum. Rum, or very similar liquors, are written about as far back as 2000 BC. It can also be traced back to the colonization of the West Indies in the 1600's. Ethyl alcohol (ethanol) is another alcohol produced from molasses, which in itself has many uses. The main uses are in vinegar, cosmetics and pharmaceuticals, cleaning preparations and solvents, and coatings. One of the future uses of ethanol which is currently being studied is as a gasoline extender. Still other products produced from molasses are butanol (a solvent), lactic acid (a solvent), citric acid (mostly for foods and beverages), glycerol, yeast, and many others (Paturau 1982).
Another useful by-product of sugar production is bagasse, the fibrous residue left after the juices are extracted from the cane. It is the main source of fuel in sugar factories. It can also be used in making paper, cardboard, fiber board, and wall board (Purseglove 1979).
The filter mud can contain up to 15% cane wax. When extracted, this wax can be used in the production of polishes and insulation. Only about one ton of wax is obtained from 1,000 tons of cane, so the process is economically feasible only under certain circumstances (McIlroy 1963).
It is quite possible that further uses of sugar cane will be developed in the future, but even now it can be seen that sugar cane is a very important and useful plant crop worldwide.
Hagelberg, G.B. 1985. Sugar in the Caribbean: turning sunshine into money. The Woodrow Wilson International Center for Scholars, Washington, D.C. 42 pp.
Heiser, C.B. 1981. Seed to civilization: the story of food. Second ed. W.H. Freeman and Co., San Francisco. 254 pp.
Jenkins, G.H. 1966. Introduction to cane sugar technology. Elsevier Publishing Co., New York. 478 pp.
McIlroy, R.J. 1963. An introduction to tropical cash crops. Ibadan University Press, Nigeria. 163 pp.
Paturau, J.M. 1982. By-products of the cane sugar industry. Second ed. Elsevier scientific Publishing Co., New York. 366 pp.
Purseglove, J.W. 1979. Tropical crops: monocotyledons. Longman Group Ltd., London. 607 pp.
Wrigley, G. 1982. Tropical agriculture: the development of production. Fourth ed. Longman Inc., New York. 496 pp.
EBL HOME PAGE