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Coping with tomorrow's unstable weather could become one of the most serious challenges for agriculture. Global warming could summon more floods, droughts, even cold snaps in some regions. Governments should encourage crop diversification to cushion their populations against the shock of climate change.
SURESH SINHA
Indian Agricultural Research Institute
The main food crops of the world were all selected at least 3,000 years ago by people with only Stone Age knowledge and facilities. Now, however, there is a new crop with high potential that could become a major staple-a man-made crop, developed during the last 100 years. Called triticale (usually pronounced trit-i-kay-lee), it is still little known, but in the future it, too, could become a staple worldwide.
Triticale is a hybrid resulting from crossing a wheat "mother" with a rye "father." It combines many of the best qualities of both its prodigious parents. It can have most of wheat's qualities for making various types of noodles, pastries, and some breads; and it can have most of rye's disease resistance, drought tolerance, hardiness, and adaptability to "difficult" soils.
Triticale was first deliberately produced in 1876, and even 20 years ago scientists in several countries grew varieties that appeared to have considerable commercial promise. To many observers at that point the plant seemed a modern miracle, and in the 1960s it was planted on thousands of hectares. However, the types then available set seed poorly, their grains were small and shriveled, and their yields were generally disappointing. To make matters worse, in some countries promoters exaggerated the crop's potential, and their claims could not be refuted easily because almost no funds were being committed to triticale research.
When word spread that some farmers had been "burned," triticale got a bad reputation.
This reputation was not justified. By the late 1970s, despite a lack of funds, a few dedicated researchers were overcoming many of triticale's technical limitations; indeed, some of their varieties were outyielding the best wheats. But by then the world was glutted with wheat, and virtually no one was interested in planting or buying any newfangled grain. Thus, triticale seemed doubly doomed to obscurity. All over the world it was abandoned.
Nevertheless, a few diehards remained convinced that one day the newborn crop would contribute significantly to global food needs. Some of them were in Canada, the first country to value the plant's modern promise Others were in Eastern Europe. Those countries, too, had been triticale pioneers, and several of them, particularly Poland, retained healthy triticale development programs.
Nonetheless, it is in Mexico that the largest program to breed triticales for human consumption has survived into the present.
Near Mexico City and at Ciadad Obregon in the northern state of Sonora, the Centro Internacional de Mejoramiento de Maiz y Trigo (ClMMYT) has maintained intensive triticale research in its laboratories and fields since 1964. It has concentrated exclusively on breeding triticales for cultivation in developing regions of Africa, Asia, and Latin America. The results have been substantial, and CIMMYT varieties, together with those of some European and American researchers, have led several countries to adopt triticale as a grain crop once again. The decade of the 1980s thus has brought renewed interest in this man-made plant with a roller-coaster history.
THE CHANGING AGRICULTURAL SCENE
In one sense, the crop and its moment are coming together. Triticale seems to be the type of robust crop that will contribute more to world agriculture in the future than it has in the past.
This is because the time ahead is one of uncertainty and of almost certain change.
In the immediate future, for example, ecological, biological, technological, economic, and social conditions all seem more likely to fluctuate than ever before. To cope with such changes, the world will increasingly need highly adaptable crops. Starting soon' consistency of yield under fluctuating conditions may be as important as maximum yield under ideal conditions.
The causes of the expected changes are discussed below.
Population Increases
The most significant force driving the coming changes is the rising number of people in the Third World. World population, currently 5.2 billion, has doubled since 1952 and will increase by almost 25 percent by the close of this century. The great majority of the 1.2 billion expected newcomers will be added to developing countries where even now ballooning population is pushing the slender reserves of arable land to the brink of exhaustion. And after the turn of the century, the situation will probably worsen. By the year 2025, for example, world population may grow by three billion. Just to sustain today's level of nourishment, food production will have to grow by 50 percent by then. In addition, if rising expectations are to be met and if food is to be provided for the millions who are currently malnourished, the increase will have to be even greater.
Limits to Agriculture
In the past, food production has been increased by modifying sites and soils to suit the needs of the dozen or so major crops. Drylands have been irrigated, wetlands drained, sloping lands terraced, barren lands fertilized, tropical forests felled, and pest-prone sites sprayed with chemicals. By these methods, supplemented with plant breeding to bring out the highest potentials within crop species, world food production has been raised to a stunning extent. Because of this, local famines notwithstanding, the massive famines widely predicted in the 1960s never materialized.
But the processes of the past three decades seem to be reaching their limits. The so-called Green Revolution, in which genetics, fertilizers, and modern agricultural techniques are employed to maximize crop yields, is in danger of running out of steam. India, for example, more than tripled its wheat harvest between 1965 (the start of the Green Revolution) and 1983, but has barely increased its grain output since.
There are several reasons for the slowdown. Not only is the prime agricultural land almost fully exploited, but the productivity of some of it is actually decreasing. Sprawling cities and villages are shrinking the area for growing crops, particularly the expanses needed for grain fields. Erosion is thinning topsoil and sometimes exposing toxic underlayers. Fertilizers and acid rain are increasing soil acidity and releasing free aluminum, which is toxic to today's conventional food crops. And pests are becoming increasingly resistant to various pesticides, which are also increasing in price and causing much public concern.
Moreover, not only is the old land almost fully exploited, but there are limits to the amount of new land that can be converted into prime farming areas. On every front, the possibility for bringing additional land under cultivation is extremely limited. For example, the potential for establishing new large-scale irrigation schemes is diminishing as industry and cities compete with farmers for dwindling supplies of water. (In fact, some irrigated land is going out of production because of the needs of cities and the buildup of salts that kill crops.) The amount of wetland that can be drained in future is being sharply reduced as the disruptive effects on wildlife and environment become more apparent. The same can be said about the amount of tropical forests that can be felled to provide farmland.
Climatic Change
The droughts that gripped the United States and China in the summer of 1988 have focused attention on a possibly deteriorating world climatic situation. Signs are ominous and appear to point to a warming trend. The 1980s have been the warmest decade in a century. The years 1980, 1981, 1983, 1987, and 1988 were unusually hot all over the world; 1987 was the hottest year on record. Based on today's trends, a rise in the earth's temperature of at least 1°C seems inevitable by the middle of the twenty-first century.
As a result of these trends, which may be associated with the intensification of the greenhouse effect, it seems likely that in the future most countries will experience more extreme weather conditions than in the past. This could affect world food production. Indeed, climates for growing today's food crops could shift, perhaps to regions where soils are too poor to support the yields necessary for feeding the planet.
CROPS OF THE FUTURE
Because of the limits to intensive agriculture and the probable climatic changes, future growth in world food output will not come easily. While some of the new human arrivals will be fed by yield increases on existing land, most will have to survive on sites that are now considered inappropriate for intensive agriculture. In future, arable cropping will have to expand onto increasingly marginal lands.
Therefore, to avoid disasters of global proportions, the world must develop an arsenal of techniques to help make today's marginal lands part of tomorrow's breadbaskets. One of these techniques is the development of crops that are vigorous, dependable, and "self- reliant."
FIGURE 1.1 Triticale is created by
crossbreeding wheat (genus Triticum) and rye (genus Secale). This is
accomplished by transferring pollen from a rye flower (the male parent) to the
stigmata of a wheat flower (the female parent). The pollen-carrying parts of the
wheat flower are first removed to prevent self-fertilization. Grains of
triticale generally are larger that wheat grains and plumper than rye grains.
(Copyright @ 1974 by Scientific American, Inc. All rights reserved)
Such crops should yield well with low inputs on substandard soils where today's crops grow poorly-crops that can withstand fluctuating environmental conditions without slumping in production.
It is for this reason that triticale is potentially important. By and large, this plant makes better use of suboptimal soils and (at least when compared with wheat) requires fewer inputs of fertilizer, lime, and pesticides. It holds promise of high performance in sites where wheat, in particular, performs poorly. This is because it has the genetic endowment of its rye "father."
Rye
In the union that makes triticale, rye is the source of pollen. A relative newcomer among foods, rye probably originated in southwestern Asia and attracted little attention before 1000 B.C., when its cultivation began both in Central Europe and in Britain. Today, it is one of the world's principal cereals, although it ranks only seventh in volume of production. Union, publishes no figures. It is believed to grow 40 percent of the world's rye-around 9 million hectares; Poland grows around 2.5 million hectares.
Rye's outstanding quality is its robustness. In poorer environments, it grows better than most other cereals. Indeed, it probably first forced itself on the attention of farmers as a vigorous, irrepressible invader of their wheat fields. Soon, however, those ancient farmers came to appreciate its vitality. Rye prospers on soils so infertile or acidic that wheat fails; it flourishes in colder climates-farther north (as far as the Arctic Circle) and higher up mountainsides (up to elevations above 4,000 m in Central Asia)-than wheat. On poor sites its yields may be low, but they are almost always higher than wheat's. Because of this ability to withstand harsh environments, it is normally relegated to the worst soils and the most unfavorable conditions. As a result, rye became known as a "rain of poverty."
"Grains of poverty" are exactly what are needed to expand food production on marginal soils. But like all crops, rye has its own problems. It is afflicted by poor pollination. It is susceptible to ergot, a fungal disease that can be toxic to people who eat it. Its grain contains at least one substance that reduces the growth of pigs and chickens. (These substances are not a problem for humans because they are inactivated by heat-for example, when bread is baked.)
Moreover, rye grain is far less popular than wheat. Like bread wheat, it contains elastic protein of the type that makes breads rise, but its flour does not rise as well as wheat flour. Nonetheless, it produces flavorful leavened breads-the dark breads and pumpernickels of Central Europe, for instance. Indeed, for breadmaking, rye is the world's second most important grain.
Wheat
In the union that makes triticale, wheat is the source of egg cells. It is a prestigious heritage. Wheat ranks first among all the world's cereals. It is our most extensive crop, the basic foodstuff for a billion people in 45 countries. More land is given over to it-about 260 million hectares in all-than to any other crop. Annual production is now more than 500 million metric tons.
Wheat is produced almost exclusively for human consumption. In developing and developed countries combined, it now furnishes 20 percent of calories and 45 percent of protein-as much protein as is derived from all the meat, milk, and eggs consumed.
The wheat plant is remarkably adaptable, but for all that, it is best suited to temperate regions, to annual rainfalls between 300 and 900 mm, and to compact but well-drained soils. It is not a good crop for many marginal lands or sites subject to climatic fluctuations. For instance, it is poorly adapted to highly acid soils, highly alkaline soils, and to regions with droughts or extremes of heat or cold.
Of the several types, the two most important are the durum wheats and common wheats. Durum wheats generally have hard grains and stiff and inelastic proteins, which make them unsuitable for breadmaking. They are used to make spaghetti, macaroni, and other pastas, as well as soda crackers.
Common wheats have soft to hard grains as a result of differing proportions of various proteins. Soft types have weak elastic proteins and are used in pastries, breakfast cereals, noodles, and other unleavened foods. Hard types generally contain a strong elastic protein (gluten) that helps retain the carbon dioxide gas, generated from yeast or baking powder, that enables bread to rise. They are used to make breads and other baked products. Despite their several uses, common wheats are generally called "bread wheats."
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