Plant Pedia: Edible Plant | Plant Biotechnology | Plant Science | Plant Tissue Culture
Showing posts with label Edible Plant. Show all posts
Showing posts with label Edible Plant. Show all posts

Friday, May 20, 2011

The Holistic Strory of Coffee as Commercial Crops


Coffee, common name for any of a genus of trees of the madder family, and also for their seeds (beans) and for the beverage brewed from them. Of the 30 or more species of the genus, only three are important: Arabian, robusta, and Liberian. The shrub or small tree, 4.6 to 6 m (15 to 20 ft) high at maturity, bears shiny green, ovate leaves that persist for three to five years and white, fragrant flowers that bloom for only a few days. During the six or seven months after appearance of the flower, the fruit develops, changing from light green to red and, ultimately, when fully ripe and ready for picking, to deep crimson. The mature fruit, which resembles a cherry, grows in clusters attached to the limb by very short stems, and it usually contains two seeds, or beans, surrounded by a sweet pulp.

Coffee grows well on the islands of Java and Sumatra and in Arabia, India, Africa, the West Indies, and South and Central America. The Americas, where Arabian coffee is grown, produce approximately two-thirds of the world's supply.


The soil in which coffee is grown must be rich, moist, and absorbent enough to accept water readily, but sufficiently loose to allow rapid drainage of excess water. The best soil is composed of leaf mold, other organic matter, and disintegrated volcanic rock. Although coffee trees are damaged easily by frost, they are cultivated in cooler regions. The growing temperatures range from 13° to 26° C (55° to 80° F). Altitudes of coffee plantations range from sea level to the tropical frost level, about 1,800 m (about 6,000 ft). Robusta coffee and Liberian coffee grow best at altitudes below 900 m (3,000 ft); Arabian coffee flourishes at the higher altitudes. The seeds are planted directly in the field or in specially prepared nurseries. In the latter case, young selected plants are transplanted later to the fields. Commercial fertilizers are used extensively to promote the growth of stronger, healthier trees with heavier yields. Both the trees and the fruit are subject to insect infestation and microbial diseases, which may be controlled by spraying and proper agricultural management.


The coffee tree produces its first full crop when it is about five years old. Thereafter it produces consistently for 15 or 20 years. Some trees yield 0.9 to 1.3 kg (2 to 3 lb) of marketable beans annually, but 0.45 kg (1 lb) is considered an average annual yield. Two methods of harvesting are used. One is based on selective picking; the other involves shaking the tree and stripping the fruit. Beans picked by the first technique are generally processed, if water is available, by the so-called wet method, in which the beans are softened in water, depulped mechanically, fermented in large tanks, washed again, and finally dried in the open or in heated, rotating cylinders. The so-called dry method, used generally for beans harvested by the second technique, entails only drying the beans and removing the outer coverings. In either case the final product, called green coffee, is sorted by hand or machine to remove defective beans and extraneous material and is then graded according to size.

Commercial Crops

The major types of commercial coffee are the arabicas and the robustas. In the western hemisphere the arabicas are subdivided into Brazils and milds. Robustas are produced in the eastern hemisphere exclusively, together with substantial quantities of arabicas. The Brazils consist principally of Santos, Paraná, and Rio, named for the ports from which they are shipped. Milds are identified by the names of countries or districts in which they are grown, such as Medellín, Armenia, and Manizales coffees from Colombia. Robustas and other arabicas are similarly identified. Green coffee is a major import of the United States; about two-thirds of the 1.2 million metric tons comes from Central and South America, with Brazil and Colombia the two largest suppliers.

Several varieties of green coffee usually are blended and roasted together to produce the tastes, aromas, and flavors popular with consumers. As a rule the beans are heated in rotating, horizontal drums that provide a tumbling action to prevent uneven heating or scorching. Temperatures for roasting range from about 193° C (about 380° F) for a light roast, through about 205° C (about 400° F) for a medium roast, to about 218° C (about 425° F) for a dark roast. The roasted beans are cooled rapidly. Roasted coffee may be packaged and shipped to retail stores, which custom grind it for the customers on purchase, or it may be ground in plate- or roller-type grinding mills before shipment.

Ground coffee loses its unique flavor within about a week unless it is specially packaged. Plastic-and-paper combinations are popular packaging media that afford protection to freshly roasted and ground coffee. Hermetically sealed vacuum, or pressure, cans keep coffee fresh for up to three years.


Coffee contains a complex mixture of chemical components of the bean, some of which are not affected by roasting. Other compounds, particularly those related to the aroma, are produced by partial destruction of the green bean during roasting. Chemicals extracted by hot water are classified as nonvolatile taste components and volatile aroma components. Important nonvolatiles are caffeine, trigonelline, chlorogenic acid, phenolic acids, amino acids, carbohydrates, and minerals. Important volatiles are organic acids, aldehydes, ketones, esters, amines, and mercaptans. The principal physiological effects of coffee are due to caffeine, an alkaloid that acts as a mild stimulant. In recent years controversy arose over the possibly harmful effects of coffee beyond those recognized for people who should take few or no stimulants, and the dangers of caffeine for the fetuses of pregnant women. These debated studies were not substantiated, however.

Kind of Coffee:

A Soluble Coffee
Soluble or instant coffee is an important production of the United States coffee industry. In its manufacture an extract is prepared by mixing coarsely ground and roasted coffee with hot water. The water is evaporated from the extract by various methods, including the use of spray driers or high-vacuum equipment. In freeze-dried coffee the coffee extract is frozen, and the water is removed by sublimation. The product is packed in vacuumized, sealed jars or in cans.

B Decaffeinated Coffee
Caffeine can be removed from coffee by treating the green beans with chlorinated hydrocarbon solvents. The beans are roasted by ordinary procedures after removal of the solvents. Decaffeinated coffee is used by people hypersensitive to the caffeine present in regular coffee. In the 1980s nonchemical methods of decaffeination became more common.

C Coffee Substitutes
The use of substitutes for coffee in the United States is limited. The most important substitute is chicory, although chicory is usually used as an extender. Under United States law, the addition of chicory or any other substance must be clearly stated on the brand label.


Exactly where and when coffee was first cultivated is not known, but some authorities believe that it was grown initially in Arabia near the Red Sea about AD675. Coffee cultivation was rare until the 15th and 16th centuries, when extensive planting of the tree occurred in the Yemen region of Arabia. The consumption of coffee increased in Europe during the 17th century, prompting the Dutch to cultivate it in their colonies. In 1714 the French succeeded in bringing a live cutting of a coffee tree to the island of Martinique in the West Indies. This single plant was the genesis of the great coffee plantations of Latin America.

Because of the economic importance of coffee exports, a number of Latin American countries made arrangements before World War II (1939-1945) to allocate export quotas so that each country would be assured a certain share of the United States coffee market. The first coffee quota agreement was arranged in 1940 and was administered by an Inter-American Coffee Board. The idea of establishing coffee export quotas on a worldwide basis was adopted in 1962, when an International Coffee Agreement was negotiated by the United Nations. During the five-year period when this agreement was in effect, 41 exporting countries and 25 importing countries acceded to its terms. The agreement was renegotiated in 1968, 1976, and 1983. Participating nations failed to sign a new pact in 1989, however, and world coffee prices plunged.
Scientific classification: Coffee makes up the genus Coffea of the family Rubiaceae. Arabian coffee is classified as Coffea arabica, robusta coffee as Coffea canephora, and Liberian coffee as Coffea liberica.

Sunday, April 10, 2011

Genetically Modified Crops in Developing Countries

By early 2003, genetically modified (genetically enhanced, as qualified by many scientists in developing countries) crops were already established in the third world: two-thirds of the 5.5 million farmers growing these crops are in developing countries, which demonstrates that small and poor farmers are also involved. In addition to maize, soybeans, rapeseed (canola) and a few horticultural crop varieties, genetically modified cotton is the fastest spreading non-food GM crop. It is currently cultivated in India, China, Indonesia, Thailand, Argentina and South Africa, and the prospects are very promising.

Illustrative regional examples of GM crops are given in later chapters. From the strategic viewpoint, the adoption of GM crops by an increasing number of developing countries, and particularly by the larger ones (e.g. China, India, Argentina), reflects the need to acquire the relevant technologies before they are completely in the hands of the industrialised countries. It also reflects the will to participate in the so-called biotechnology revolution and even to become formidable competitors in some areas, instead of just purchasing and adapting biotechnologies. China's huge commitment to plant biotechnology, through increasing five-fold the funds devoted to this area of endeavour (US $500 million annually by 2005) is illustrative of this trend.

Another key element in the strategy of developing countries is to improve their competitiveness in international commodity and agricultural product markets. For those who are big exporters and whose agriculture is not subsidised, GM crops and agricultural biotechnology can contribute to decreasing production costs (e.g. through the reduction of use of biocides) and to increasing farmers' incomes. This aspect has been clearly demonstrated for GM soybeans in Argentina and GM cotton in South Africa and China.

This strategy also requires the design and update of biosafety regulations, the establishment or revision of intellectual property legislation and active participation in the negotiations on trade-related issues at the World Trade Organization.

Adopting GM crops is not synonymous with exclusion of other forms of agriculture, particularly the so-called biological or organic agriculture. A number of developing countries, e.g. Argentina and Chile, have an important and prosperous organic agriculture sector, which they wish to preserve and even extend because of its commercial benefits (e.g. Chile exports high volumes of ‘organic’ products to Japan and the European Union). Nevertheless, the advantages offered by GM crops enable developing countries to meet more rapidly the need to establish higher yielding, stress- and pest-resistant crop varieties, particularly when one has to deal with pathogens and pests against which there is no known natural resistance or tolerance.

Naturally, the developing countries are carefully following the controversy on GM crops in the European Union member countries as well as the disaccord between those countries and the USA in this respect. They are vigilant at the World Trade Organization, the Codex Alimentarius Commission on GM organisms and their impact on health and nutrition, in order to safeguard their interests. They generally consider that agricultural biotechnology and GM crops can help them to face the challenges of sustainable agricultural development. In this respect, their position is not far from that of the representatives of farmers in industrialised countries who welcome these technologies and maintain the highest standards of biosafety and biovigilance. They also consider, to a large extent, that the precautionary principle (now called the precautionary approach, since the 2002 Earth Summit in Johannesburg) should not become a dogma that hampers research, trials and large-scale cultivation. They agree on the need for biovigilance as in the case of medicines.

With regard to labelling and traceability of GM or biotechnology-derived products, developing countries tend to refer to substantial equivalence of these products compared to conventional ones, and to adopt labelling when there are substantial differences in composition. Thus, sugar, starch or vegetable oils derived from GM crops should not be labelled as GM. They are pragmatic in discussing the minimum percentage of GMOs in foodstuffs and agricultural products, the threshold of 0.9% (proposed by the European Union's Council of Ministers) being considered as unrealistic.

Finally, developing countries support the strengthening of regulatory institutions and biosafety measures, but they wish to avoid over-regulation, which will hinder their competitiveness. There is also a growing trend of improving public perception and social acceptance of agricultural biotechnology in developing countries, involving the participation of all sectors of society.
Confronted by the urgent need to feed their people and make their agriculture more competitive on international commodity markets, the developing countries, be they food exporters or not, have resisted the adoption of a moratorium on the cultivation of GM crops like that in Europe. In contrast, they wish to draw benefits from modern agricultural biotechnology and seize the opportunities offered to them.

In addition to the competitive edge provided to the commodity-exporting developing countries, agricultural biotechnology must reach resource-poor farmers—a large majority in developing countries. For such a purpose, it is necessary to carry out the social analysis of these technologies, when they are transferred to the farming communities. It is also necessary to pay great attention to the so-called orphan crops such as sorghum, millet, cassava, yams, sweet potato, etc., which do not attract the big seed corporations, but which play a vital role in local and national economies.

While favouring a sustainable diversified agriculture, including agricultural biotechnology, and making special efforts to help the resource-poor farmers, developing countries can protect their biological diversity (e.g. through the conservation of potentially useful varieties), clone crops on a large scale and participate in the selection of new varieties with the appropriate traits. Many projects being carried out in developing countries reflect these goals, while at the same time key issues, such as biosafety regulation, risk assessment and management, intellectual property rights and training of human resources are dealt with.

There are undoubtedly, in this vast area of research and development, opportunities for collaboration among the developing countries but also between them and industrialised countries' public research centres, enterprises and professional associations. In this regard, we are dealing not only with solidarity, but also with mutually beneficial cooperation in important international markets.

Thursday, March 17, 2011

History of Rice

According to the most widely accepted theory, rice cultivation originated as early as 10,000 BC in Asia. Archaeological evidence shows that rice was grown in Thailand as early as 4000 BC, and over the centuries spread to China, Japan, and Indonesia. By 400 BC rice was cultivated in the Middle East and Africa. The invading armies of Alexander the Great probably introduced rice to Greece and nearby Mediterranean countries around 330 BC. Rice was brought to the American colonies in the early 1600s, and commercial production began in 1685.

Rice cultivation, a very demanding process, has shaped values and changed history. For example, rice encouraged populations to crowd together to take advantage of a reliable food supply. The labor-intensive process of growing paddy rice requires large numbers of people to work together to level fields, build and maintain bunds, and care for the crop. Where paddy-rice cultivation has been introduced, hard work, organization, persistence, and above all, cooperation, have been encouraged.

In the United States, rice played an important role in establishing slavery in the coastal Southeast—the Carolinas, Georgia, and north Florida. For instance, rice exportation was deemed necessary for economic survival in Georgia, and as a result, slavery was legalized in that state to create a work force to clear swamps, install dikes, and plant, grow, harvest, and thresh the rice.

Production And Using of Rice

Asian countries produced about 90 percent of the 576 million tons of rice grown worldwide in 2002. Typically, China and India together produce about 50 percent of the world’s rice, and it is a significant agricultural crop in more than 50 other countries. About 96 percent of the rice grown worldwide is consumed in the countries where it is produced, with some exceptions. The United States, for example, exported about 37 percent of the 8.7 million tons it produced in 2000, and Pakistan exported about 28 percent of its 7.2 million tons, according to the FAO. In the same year, Thailand exported significantly more rice than any other country—6.6 million tons, or about 26 percent of its total, while India exported 1.5 million tons, or about 1.1 percent of total production. Major rice-importing countries include Côte d'Ivoire, Nigeria, Philippines, Iran, Saudi Arabia, Brazil, Senegal, Japan, and Indonesia. Some rice-importing countries buy rice on a regular basis, others buy when drought, floods, or other conditions reduce the yield of their own rice crop.

Rice is used for a variety of food and nonfood products. Foods include cooked rice, breakfast cereals, desserts, and rice flour. Rice is also used in beer and in sake, a Japanese fermented brew. The inedible rice hull is used as fuel, fertilizer, and insulation, while the bran is a source of cooking oil. Straw from the leaves and stems is used as bedding for animals and for weaving roofs, hats, baskets, and sandals.

Growing Rice

Although rice originally flourished in the dry climate of Central Asia, it spread to the flood plains of tropical regions, resulting in evolution of varieties with the capacity to grow with roots submerged in water. The African and Asian varieties that are flooded during the growing season are more productive than the varieties that are not flooded, partly because the submerged roots easily extract needed nutrients from the water. Flooded rice, also known as lowland rice, is grown in paddies, which are fields that contain water enclosed by low walls of earth called bunds. Paddy rice fed by rainfall alone accounts for about 50 percent of all rice grown worldwide, while paddies flooded by a combination of rainfall and irrigation provide about 35 percent of rice produced. The major rice-producing countries, including China, India, and Vietnam, primarily cultivate paddy rice.

Other African and Asian rice varieties, known as upland rice, are grown in regions of low rainfall that do not provide enough moisture for paddies, or in tropical rain forests where high humidity prevents the ripening of other edible grains. Upland rice is less productive than paddy rice, partly because it depends on nutrients that are dissolved in the soil moisture. When soil moisture is low, few nutrients are available, compared to the storehouse of nutrients typically found in paddy waters. Upland rice accounts for about 15 percent of world rice production, and is particularly important in Laos, where it accounts for between 20 and 22 percent of the rice harvest.

Rice, grown in more than 100 countries, is particularly productive in tropical regions with abundant moisture, but it also grows successfully under widely different climate conditions. Rice farmers choose varieties adapted to the region’s length of growing season, soil, altitude, and, for paddy farmers, the depth of water in the fields. Paddy rice farmers in developing countries usually sow seeds in small seedbeds, then hand-transplant the seedlings into flooded fields that have been leveled by water buffalo or oxen-drawn plows. One advantage of transplanting seedlings instead of planting from seed is that the young plants help limit weeds by shading them from needed sun. In industrialized countries, seed is sown with a planting drill or cast from an airplane into machine-leveled fields that are then flooded. Herbicides are the primary method of weed control.

Depending on the rice variety and the climate, rice grains are ready for harvest in three to six months. In developing countries, farmers harvest rice with sickles or knives, tie it in bundles, and let it dry in the field. They then remove the grain from the plant, a process called threshing, by hitting the plant against a slatted screen or walking animals over it. Farmers in industrialized countries use combines, which are machines that move through fields and harvest, thresh, and clean the grains. The grain is then dried in sheds with heated air.
Rice is susceptible to a range of diseases and pests, which annually destroy about 55 percent of rice crops. The most common diseases are caused by the fungi sheath blight and rice blast, and the stalk borer is a common insect pest. Weeds compete with rice for nutrients and water and are a serious problem, especially in upland rice farming. Rodents and birds also feed on rice grains before they are harvested. Disease-causing fungi, insects, and a variety of other pests infest rice during storage and transport.

When rice is processed, the hull is removed, exposing the bran. Rice at this stage is brown rice. The fibrous bran of brown rice is rich in oil; protein; the B vitamins thiamin, riboflavin, and niacin; and the minerals iron, phosphorus, and potassium. To make white rice, the bran is removed. White rice is less nutritious than brown rice and, when feasible, is enriched with the addition of vitamins and minerals to increase its nutritive value. Without the tough bran layer, white rice cooks faster and stores longer than brown rice, so it is often preferred in regions where fuel is limited and refrigeration is not readily available. Polished rice is made by passing white rice kernels through a machine with a brush that smoothes and shines them.

Rice as an edible grain

Rice, plant that produces an edible grain; the name is also used for the grain itself. Rice is the primary food for half the people in the world. In many regions it is eaten with every meal and provides more calories than any other single food. According to the United Nations Food and Agricultural Organization (FAO), rice supplies an average of 889 calories per day per person in China. In contrast, rice provides an average of only 82 calories per day per person in the United States. Rice is a nutritious food, providing about 90 percent of calories from carbohydrates and as much as 13 percent of calories from protein.

Of the 20 known species of rice, only two are cultivated—the widely grown Asian rice and the hardier African rice. Asian rice, if managed with modern techniques such as fertilizers, irrigation, and chemical pesticides, produces significantly more grain per plant than African rice, and for this reason is the preferred type in the majority of rice-growing countries. African rice, however, is more productive than Asian rice in traditional farming systems where modern techniques are not used or poor growing conditions are present. About 50,000 varieties exist within these two species, only a few hundred of which are cultivated.

covering, surrounds the bran, which consists of layers of fibrous tissue that contain protein, vitamins, minerals, and oil. Beneath the bran is the endosperm, which makes up most of the rice grain. The endosperm contains starch, the energy source used by the germinating seed. The bran and endosperm are the edible portions of the grain.

A rice plant, a type of grass, has narrow, tapered leaves and grows from about 60 to 180 cm (about 2 to 6 ft) tall. Several flower stalks emerge from the plant, and in most varieties, a loose cluster of branching stems, called a panicle, radiates from the top of each stalk with small green flowers hanging from each stem. When the grain has developed, the panicle droops under the weight of the ripened kernels. Depending on the variety, one panicle provides about two handfuls of rice.