5.1. Background
5.2. Cereals
5.3. Roots, Tubers, Banana and Plantain
5.4. Food Legumes
5.5. Oil Crops
5.6. Vegetables
5.7. Other Crops and the Issue of Self-Reliance
Crops and their products provide 57% of the total value of production of agriculture, forestry and fisheries in developing countries. In Asia this share amounts to 58%, in sub-Saharan Africa 53%, in Latin America and the Caribbean 51% and in West Asia-North Africa 69%.
Research to improve the productivity of the most important food crops in developing countries has been the central theme of the CGIAR since its inception. The CGIAR has a multidisciplinary research approach to increasing crop productivity. The research has four main objectives: to increase yield potential; to narrow gaps between potential and actual yields; to improve yield stability; and maintenance research to prevent the erosion of attained yield levels. Crop productivity research in the CGIAR consists of five activities: germplasm enhancement and breeding, cropping systems, plant protection, plant nutrition, and seed technology and production. (These five activities fall into two of the major categories of activities identified in Section 2.1, germplasm enhancement and breeding, and the development and management of production systems.)
The pay off to crop productivity research in the CGIAR has been large, and the impact of research on rice and wheat has been particularly impressive (Anderson et al, 1988). Significant farm-level impact has also been achieved through research on maize, millet (particularly in India), groundnut (in India) and phaseolus beans. Although encouraging progress in the development of technology for the other crops has been achieved, evidence of impact is still largely anecdotal. Progress has been particularly slow for grain legumes.
This chapter discusses important factors for the allocation of CGIAR priorities to particular crops. For each crop under consideration, the importance of the commodity in the diet and the production system, research opportunities and history, the strategic breeding goals, and the role of the CGIAR hitherto are highlighted. Implications with respect to the future priority ranking of each commodity are discussed in Section 12.3.5.
TAC acknowledges the importance of mixed cropping systems and the difficulty of allocating priorities to the crops involved, which are often of minor importance globally but can play a significant role in particular farming systems. In addition, for many crops, particularly roots and tubers, food legumes and vegetables, the database is weak. Estimates on their value of production and yield levels are often crude guesses, and in a quantitative analysis these crops may, therefore, get a lower priority ranking than they merit.
5.2.1. Rice
5.2.2. Wheat
5.2.3. Maize
5.2.4. Barley
5.2.5. Sorghum
5.2.6. Millet
Globally, rice is the most important crop in terms of its contribution to diet and value of production. Of the 147 million ha harvested globally in 1989, more than 142 million ha were in developing countries, producing 460 million tonnes of paddy. Asia is the primary producer, accounting for 91% of production in developing countries. Latin America and the Caribbean accounts for 4 %, West Asia-North Africa for 3 %, and sub-Saharan Africa for 2%. Rice provides between 35% and 60% of the calories consumed by 2.7 billion people in Asia, and 8% of food energy for 1 billion people in sub-Saharan Africa and Latin America and the Caribbean. Only about 4% of world rice production is traded on the international market; most countries rely almost entirely on domestic production to meet their demand. Price formation on the international market is heavily influenced by subsidies and other protective measures. In West Africa and Latin America rice is a relatively new staple in the diet. Per caput consumption in West Africa has doubled over the past two decades, while in Latin America it has increased by about 25%.
Rice production increased in varying degrees in all developing regions during the 1970s, by an average of 2.7% annually, and during the 1980s, with an overall average of 3.0%. About two-thirds of the increase can be attributed to higher yield levels in irrigated rice in Asia, attained through the widespread adoption of high-yielding varieties, fertilizer and irrigation. Production increases in Latin America and the Caribbean resulted largely from the spread of new varieties. However, in sub-Saharan Africa and West Asia-North Africa they resulted from an increase in the area cultivated rather than from increases in yields. Over the two decades, the rice areas of 11 green revolution countries in Asia showed a mean yield increase of 63% (from 2.03 to 3.31 t/ha). However, yields vary widely between countries in all developing regions. For example, in Asia the average yield of rice in India, which has one-third of the region's rice area, is only 2.13 t/ha, whereas it is 5.33 t/ha in China, which also has about one-third of the region's rice area. Yields in South Korea are about 7 t/ha.
If past trends in demand continue, world rice production will need to increase by 21% by the end of the century, and by 65% by 2020 (1.7% annually). While Asia has achieved marginal self-sufficiency in rice for the present, further increases through higher yields or increased cropping intensity will be necessary to keep pace with demand. The leading rice-growing countries in Asia will need to increase their rice production by 100% by 2020 (2.3% annually).
These escalating demand levels will require a concerted research effort to continue the development of improved technologies for production. To date, the pay off from CGIAR investments in rice research has been large. The internal rate of return from international rice research over the last 30 years can reach at least 80%, and during this period the new rice varieties allowed for an increase in rice production which was sufficient to feed about 600 million more people (IRRI, 1991). The impact of new technology has so far been confined primarily to irrigated areas - which make up some 50% of the world's harvested rice area - and to favourable rainfed areas. Further research must be conducted for these areas to protect and build on what has already been achieved. Recent work at IRRI has given strong indications that the high yield levels obtained on farms with favourable management conditions are not sustainable due to a variety of factors such as poor quality of irrigation water, the lack of micronutrients, and the vulnerability of improved varieties to pests and diseases. In order to meet the problem of yield erosion, further efforts in maintenance research, as well as in lifting the yield ceiling, will be required. However, if rising demands are to be met, other rice growing systems will also have to receive attention. These include: shallow rainfed rice, which accounts for almost 25% of the harvested area in Asia; deep-water and floating rice, which accounts for about 13% of the harvested area in Asia; and dryland or upland rice, which accounts for 75% of the harvested area in Latin America and the Caribbean and 50% of that in sub-Saharan Africa.
In 1983, 25% of total CGIAR allocations were spent on rice. In 1985, TAC recommended that the overall effort for rice be reduced and that the existing shift in research emphasis away from applied research on irrigated systems be reinforced. TAC considered that the CGIAR System's future efforts on rice should concentrate more on non-irrigated systems, and in basic research on irrigated rice in collaboration with specialized institutions.
These recommendations reflected the successes that had already been achieved in rice research, especially in the more favourable environments. Today, more than two-thirds of the rice lands of developing countries are planted with high-yielding modem varieties. Furthermore, the CGIAR System's collaboration in rice research has significantly strengthened many national research programmes, allowing them to assume an increasingly large share of the responsibility for research. This is particularly true of some of the largest rice producing countries, e.g. India, Thailand, the Philippines, Bangladesh, China and Korea.
Non-irrigated wetland and dryland rice systems comprise almost half the global area under rice production. The production constraints of these systems are more complex than those of irrigated rice because of the lack of control in water management and the more limited knowledge base for research. In Latin America and the Caribbean and in sub-Saharan Africa, CGIAR emphasis has shifted to dryland rice research.
The 1986 recommendation for the movement towards basic research was made in the belief that the exploitation of genetic diversity was fundamental to achieving higher and more stable yields, resistance to major pests and disease, and better drought tolerance. For both irrigated and non-irrigated rice, it will be necessary to develop new and better breeding techniques, to increase knowledge of the factors determining resistance and tolerance, and to raise yield potential by using biotechnology. The CGIAR System should therefore emphasize strategic research. In so doing it will catalyze and support basic research in other institutes, and play an active role in encouraging the application of new techniques to the rice production problems of developing countries.
In considering future priorities for rice research, TAC should also consider the substantial impact obtained from CGIAR efforts in rice research, particularly in Asia, and Latin America and the Caribbean.
After rice, wheat is the single most important food source in the developing world, contributing more calories to diets than all other cereals combined. It is higher in protein content than almost all other cereals. Within wheat, a distinction can be made between durum and bread wheats, and between bread wheats, between winter, facultative and spring wheats. Durum wheat accounts for 5% of developing country wheat production, and 70% of it is grown in West Asia-North Africa.
In 1989, developing countries accounted for 42% of world wheat production (538 million t) and 44% of world wheat area (226 million ha). Half the total increase in production in the 1970s and 70% in the 1980s came from the developing world. In 1989, Asia accounted for 71% of the developing world's production, West Asia-North Africa for 17%, Latin America and the Caribbean for 10% and sub-Saharan Africa for 2%. In the West Asia-North Africa region, wheat is the most important food crop in terms of its calorie contribution.
Wheat production in the developing regions as a whole increased by 5 % annually in the 1970s and by 4.3% in the 1980s. The five largest producers - China, India, Turkey, Pakistan and Argentina - raised production at an average annual rate of 5.4% in the 1970s and 4.3% in the 1980s, largely through yield increases. In the remaining developing countries, the growth rate was only 1.5% during the 1970s, but increased to 3% during the 1980s. Trends in yield levels over the past two decades have varied considerably. China experienced an increase of 75% in the 1970s and 49% in the 1980s; India 25% in the 1970s and 45% in the 1980s; West Asia-North Africa 35% in the 1970s and 16% in the 1980s, sub-Saharan Africa 55% in the 1970s and 38% in the 1980s; Latin America and the Caribbean 37% in the 1980s. Improved varieties and associated technologies have had a major impact on wheat production in the developing world, causing an absolute yield increase from 1.64 t/ha to 2.23 t/ha in the past decade. Today, some 60% of the wheat lands in developing regions are sown with modern varieties.
Wheat imports by developing countries doubled in the 1970s and further increased substantially in the 1980s. Many countries financed their purchases of wheat with limited foreign exchange, indicating the high priority assigned to wheat as a food. Even the countries that produce wheat have become more reliant on imports during the past two decades. Among countries consuming 100,000 tonnes or more annually, per caput wheat imports declined only in Turkey, India, Pakistan and Zimbabwe.
Growth rates in consumption are closely linked to rising incomes and urbanization. The correlation with rising incomes reflects not only greater overall food consumption, but also a switch to wheat in preference to other starchy staples, and the use of wheat as animal feed. In West Asia-North Africa, where wheat originated, consumption is high at all income levels and in both rural and urban areas. Other factors contributing to increased wheat consumption are the lagging production of many other staple foods; and food aid and pricing policies, which lower wheat prices and create a bias in favour of wheat products.
For the developing regions as a whole, the annual demand for wheat is projected to grow at 3% over the coming decade. Demand will rise particularly rapidly in sub-Saharan Africa, at 5.1% per annum, and at 2.9% in other regions.
Expansion in wheat area has declined from 1.7% per year in the 1950s to under 1% currently, and is projected at 0.8% in the future. Consequently, wheat yields will need to rise by 2.2% each year to meet the projected demand growth of 3%. Semidwarf wheat varieties are already sown in most of the wheat area and fertilizer applications are relatively high on much of the irrigated land. However, in most developing countries absolute yields are still comparatively low, less than half the average yield in Europe. Even the current yield levels of the five largest producers cannot be considered high: China, 3.05 t/ha; India, 2.24 t/ha; Turkey, 1.97 t/ha; Pakistan, 1.86 t/ha; and Argentina, 1.85t/ha.
Diseases, insect pests and environmental stresses, especially drought, are important constraints but they are not the only ones: crop and water management, socioeconomic factors and the policy environment are equally important for achieving further sustainable increases in yield. The impact of CGIAR investments in wheat research has been impressive. Varieties to which CIMMYT has contributed, now cover about 47 million ha, and between 50% and 70% of improved wheat varieties released during the last 30 years have been based on crosses made by CIMMYT.
In the West Asia-North Africa region, where most of the wheat is rainfed, winter rainfall is low and erratic and crop yields are limited by biological and environmental constraints as well as by management and socioeconomic factors. Except in Turkey, research in this region has not addressed the needs of high elevation areas, which require winter or facultative wheat varieties with tolerance to a range of environmental stresses, including cold. In the lowland areas of the West Asia-North Africa region, tolerance to heat and salinity, as well as to cold, are required. For the lowland irrigated areas of the semi-arid tropics and subtropics with summer rainfall, where the crop is grown during the cool season, varieties with better tolerance to relatively high temperatures are required. Aluminium toxicity is a constraint to bread wheat production in large areas of highly leached acidic soils in the subhumid and humid subtropical areas of southeast China. For the higher elevation areas of the cool tropics and subtropics with summer rainfall, spring wheat varieties with better adaptation to biotic and abiotic stresses are required. According to the ACIAR analysis, the highest pay off from future investments in wheat research can be obtained in the warm and seasonally dry subtropics with summer rainfall, and in the cool subtropics.
In its 1986 assessment of priorities, TAC considered the importance of wheat as a food crop and the increasing reliance of developing countries on wheat imports. It also considered the strong research programmes on wheat in developed countries and the growing strength of national programmes in Latin America, Turkey, India and China, as evidenced by the remarkable yield and production increases achieved in those countries during the 1970s and 1980s. The well organized international wheat trade, the export capacity of some developing countries, and the increasing demand for wheat in countries with unfavourable environments for its production make the concept of self-sufficiency inappropriate for many areas.
In 1986 TAC considered that the trend of the centres concerned to transfer a number of research functions to national systems while continuing to provide them with technical support was reasonable and should be accelerated. This led to the recommendation that the System's overall efforts in wheat research should be gradually reduced by 10% over the following five years. TAC also recommended that research should concentrate on increasing production on marginal lands, including those in tropical areas.
A major share of CGIAR efforts on wheat are now allocated to maintenance research. The pay off from investment in wheat research has been very high, but further efforts are required to sustain the increased yield levels achieved.
Among the food crops, maize ranks third after rice and wheat both in terms of calorie contribution and in terms of value of production. Developing countries produce an estimated 39% of world production (470 million t) from about 81 million ha (63% of total maize area). The crop is grown in all the developing regions. Of the total for all regions, China alone accounts for 41%, Latin America and the Caribbean for 27%, the rest of Asia for 13%, sub-Saharan Africa for 9%, and West Asia-North Africa for 7%.
Where grown for human food, maize is an important source of calories for the poor. The crop is widely grown in mixed cropping systems by subsistence farmers. For all developing countries, annual per caput human consumption is only 20 kg, but in Latin America and the Caribbean (the homeland of maize) it is 80 kg, and in sub-Saharan Africa 60 kg; in some countries of both regions, per caput human consumption is as high as 100 kg per annum. Maize provides about one-third of the mean calorie intake in these two regions, but little more than 5% in the other regions. Maize stover is an important byproduct in many countries.
The use of maize for livestock feed has become increasingly important and now accounts for about 54% of consumption in developing countries. In the subtropical areas of South America, it is the main use, and it is important for this purpose in the rest of Latin America and the Caribbean, and in the West Asia-North Africa region. In the 1970s and the 1980s, the use of maize as feed in developing countries grew by 5.3% per annum, and in Asia and West Asia-North Africa it grew at three times the rate for direct human consumption. It grew at twice the rate for food use in sub-Saharan Africa, but from a low base, so that use of maize for feed is still relatively low in that region.
During the current decade, demand for food maize for the developing regions as a whole is expected to grow at 1.6% per year, for feed maize at 4.9%, and for food and feed maize combined at 3.5%. Total regional demand is projected to grow at 3.1% for sub-Saharan Africa, 3% for the West Asia-North Africa region, 3.8% for Asia and 3.3% for Latin America and the Caribbean.
During the past decade, developing countries achieved a 22% increase in yields. However, this average figure masks China's considerable gain of 50% (associated largely with the adoption of improved varieties) at one end of the scale, and a decline of almost 15% in West Africa at the other. The variation in yields per ha is equally dramatic: these range from more than 3 t in subtropical South America and China, through just under 2 in West Asia-North Africa, to about 1.6 in Central and tropical South America, about 1.5 in South and South-East Asia, about 1.1 in East and Southern Africa and India, and less than 1 in the other sub-Saharan African regions. Sub-Saharan Africa achieved some increase in production during the 1970s, but this was the result of an increase in the area harvested. During the 1980s, yield gains were 16% (from 1.96 to 2.28 t/ha) for the developing regions as a whole, 12% for sub-Saharan Africa, 7% for Latin America and the Caribbean, 38% for West Asia-North Africa and 27% for Asia.
In the long term, the global pattern of use will continue to change with rising incomes and urbanization. Although consumers in developing countries will tend to spend less on maize as they switch to other foods, maize consumption will increase because of its increasing use as feed. In the low-income countries, particularly in sub-Saharan Africa, this scenario is likely to develop more slowly, and in the medium term the problem will be one of increasing demand for maize for human consumption against a background of declining per caput production. For example, in East and Southern Africa, where maize is the staple food and is grown on about 30% of the cultivated crop area, production will need to double by the year 2000 if the region is not to face massive bills for food imports. Increased production in sub-Saharan Africa will need to come mainly from increased yields.
The potential for increasing yields is quite high and the pay off from CGIAR investments in maize research has been substantial, particularly in the lowland tropics. The main constraints are environmental stresses (particularly drought), diseases and insect pests, and low levels of external inputs. Both improved open-pollinated varieties and hybrids are required, depending on local needs and the efficiency of national seed producers. In the lowland tropics, the development of better varieties and improved management practices relevant to farmers' needs and constraints would contribute considerably to improved production. In sub-Saharan Africa, low fertilizer rates and poor management currently pose a greater constraint than does the availability of high-yielding varieties. In East and Southern Africa, where there are extensive lowland and highland areas ideally suited to maize production, the pay off from the development of appropriate technology for small-scale farmers is exceptionally high, as the case of Zimbabwe shows. In some environments with bimodal rainfall, short-cycle maize outperforms both sorghum and millet.
In 1986 TAC considered that the CGIAR System's major effort in maize research was justified and should be maintained over the long term, and that some additional support should be given in the short to medium term to accelerate the promising results from work in progress. The recommendation took into consideration the crop's value as food, feed and a source of income for low-income groups and small-scale farmers worldwide; the projected increase in demand; and the expectation that strategic research could successfully address the constraints to higher yields in many developing countries. TAC recognized the urgent and specific needs of sub-Saharan Africa and recommended a shift of effort to those areas where maize is the staple food.
Barley is grown throughout the world and is tolerant of many soils and climates, but like wheat it is not well adapted to warm, humid conditions. It does, however, require less moisture than wheat. Its most important uses are for animal feed and making malt; little is used as human food, although average data conceal its local importance for food in some developing countries. The CGIAR System has not been involved with research for the improvement of malting barleys.
Developing countries account for about 14% (1.33 million t) of global production and 16% (16.2 million ha) of the harvested area. West Asia-North Africa accounts for 71% of the harvested area in the developing regions, Asia for 18%, sub-Saharan Africa for 7% and Latin America and the Caribbean for 4%. Some two-thirds of the production is in West Asia-North Africa, and in no other developing region is the crop as important relative to other commodities. Asia accounts for another 28% of production, China for 14% and India for 12%.
In West Asia-North Africa, barley is grown primarily as a feed crop and is inseparable from the production of sheep and goats. It is the principal crop in areas that receive 200-300 mm rainfall. It is estimated that barley provides almost half the annual digestible energy needs of sheep in such areas. Grain, straw and stubble all provide important sources of feed at different times of the year.
Current yields average 1.43 t/ha for all developing countries and 1.25 t/ha for West Asia-North Africa. In the 1970s, there was a decline in the area sown in developing countries, and the modest production increase of 13% over that period is attributed to increases in yield. The average yield increase was 30%, from 1.0 to 1.3 t/ha, but China's gain was an impressive 119%, from 1.1 to 2.4 t/ha, while that of West Asia-North Africa was only 15%, from 0.96 to 1.1 t/ha. During the 1980s there was an increase of about 4% in the harvested area and a 15% increase in production, so nearly three-quarters of the latter increase was due to yield gain. Average yield increase was 11% (from 1.09 to 1.43 t/ha) for all the developing regions combined, 28% for China, 41% for India, and 10% for West Asia-North Africa.
The livestock industry accounts for almost one-third of the value of agricultural production in West Asia-North Africa, and the increasing demand for meat will mean an increased demand for barley as feed.
The main constraints to improved production are environmental stresses (especially drought), and insect pests and diseases.
In 1986 TAC recommended that the overall allocation to barley research be reduced slightly, but that the effort for West Asia-North Africa be strengthened by phasing out research for other regions. The recommendation took account of the relatively low importance of barley elsewhere (excluding barley grown for malt) and the strength of many national agricultural research programmes.
Some 70% (62 million t) of the world's sorghum production and 89% (45 million ha) of its sorghum area are located in the developing regions. Sorghum is a major crop of the lowland semi-arid tropics and subtropics with summer rainfall, where it has a special importance, together with millet, as a staple food for millions of very poor people in drought-prone, high-risk areas. In West Africa, sorghum is an important crop in the subhumid areas, where it is intercropped with millet, maize and cowpea. Sorghum is also an important crop in the medium-altitude areas of Ethiopia. Sorghum tends to have a low or negative income elasticity of demand, and is usually substituted by other foods when income permits. In most areas, the stalks and foliage - used as fodder, fuel and construction materials - are more important than the grain.
Although the average contribution of sorghum to diets may be low in most developing regions, in semi-arid West Africa it contributes 13% of calorie intake and over 11% of protein, making it the second most important food commodity after millet. In India, it accounts for almost 6% of calorie intake. In Latin America and the Caribbean, most of the crop is used for feed.
Of the area harvested in developing countries, Asia accounts for 46%, sub-Saharan Africa for 31%, West Asia-North Africa for 12% and Latin America and the Caribbean for 10%. India, the largest single producer, accounts for 39% of the sorghum area in the developing regions and China for 5%. In sub-Saharan Africa, some 60% of the sorghum area is located in West Africa, the rest in East and Southern Africa. However, there is little correlation between area harvested and production share because of the considerable regional variation in yields: these range from 3.5 and 3.2 t/ha in Peru and China respectively to 0.74 t/ha in India and 0.9 t/ha in West Africa, where many national averages are even lower.
In the 1970s, substantial yield increases were achieved in China, Latin America and the Caribbean, and India, from a very low level in the latter country. During the 1980s, sorghum area in Asia declined by 10% and production by 6%, the balance being offset by a 4% increase in yield. In sub-Saharan Africa, sorghum area increased by 17% during the 1980s, and this was associated with a yield increase of 9%. In Latin America and the Caribbean, there was a 12% decrease in the sorghum area, accompanied by a yield increase of 4%.
The world's most urgent food production problems lie in drought-prone areas such as those of India and the Sahelian zone of Africa, where sorghum and millet are the staple food crops. The events of recent years have demonstrated as never before the extreme vulnerability of such areas, where the effects of a series of bad years have led to famine and dependence on food aid.
Crop stands are usually poor in such areas, and a special problem is poor plant emergence because of low and erratic rainfall, soil crusts and attacks from shoot flies and stem borers. Striga sp. (witchweed) causes serious losses where the land is planted to successive crops of sorghum; and bird damage, especially due to Quelea sp., is a serious problem throughout sub-Saharan Africa. Storage pests are also a problem.
In 1986 TAC recommended that the level of effort on sorghum be increased immediately and that the main effort should continue to be directed to sub-Saharan Africa, where research needs and opportunities were greatest. India, China and Latin America and the Caribbean, due to either relatively strong national programmes or the development of the private-sector seed industry, had less need of assistance.
One of the major objectives of this recommendation was to bring research support on sorghum (and millet) in sub-Saharan Africa to a level comparable with that of maize, so that suitable varieties and other technologies of most value to some of the world's poorest people could be developed as quickly as possible.
In Asia and sub-Saharan Africa, pearl millet is the most important crop in the lowland semi-arid tropics and subtropical areas with summer rainfall, where it is a staple food together with sorghum (in sub-Saharan Africa), or with wheat (in Asia). Millet provides food for some of the world's poorest countries and poorest people. It can produce under conditions too dry for sorghum, and its straw is a valuable livestock feed.
Because some countries combine their statistics for sorghum and millet, the data for millet tend to be overestimated, especially for sub-Saharan Africa. It would appear that the crop is harvested from about 40 million ha in developing countries, with India accounting for about 45% of that area and West Africa for about 32%. Millet is the staple cereal in the Sahelian zone of Africa. In semi-arid West Africa, it accounts for about half the daily calorie intake and one-third of the protein.
Average yields are only 500 to 700 kg/ha. Yields remained stagnant during the 1970s but showed a modest increase of 12% during the 1980s. Whereas developing world production declined during the 1970 (with a slight increase in West Africa), it increased by 13% during the 1980s, mainly due to yield increases (12%). In sub-Saharan Africa, the area under production increased by 18%, and this was accompanied by a 14% increase in yield. In Asia, the area decreased by 12%, but yields rose by 15%, leading to a 3% increase in production. However, unless millet yields can be further improved and stabilized, the future for rainfed food production in the semi-arid tropics will continue to look bleak. In India, ICRISAT's efforts have met with substantial success: more than 4 million ha or a third of the area cultivated is now planted with improved millet varieties that originated at ICRISAT.
The main constraints to production are the same as those for sorghum: environmental stress (especially drought), crop establishment, insect pests and diseases, and Striga sp.
In 1986 TAC recommended that the level of effort on millet be increased over the short term, with a greater concentration on the needs of sub-Saharan Africa. The recommendation was based on the crop's importance in meeting the needs of the poor in sub-Saharan Africa and India, the fact that people in the driest areas of the semi-arid tropics depend on it for survival, the short research history, and the weak national research programmes in the millet producing countries of sub-Saharan Africa. Continuing development of improved varieties and crop management practices is required. The control of Striga, drought tolerance, and germination and establishment in crusting soils should remain as areas of particular focus.
5.3.1. Cassava
5.3.2. Potato
5.3.3. Sweet potato
5.3.4. Yam
5.3.5. Banana and Plantain
Cassava is an important food crop in sub-Saharan Africa, particularly in the humid and subhumid tropics. It is also important in parts of Asia and Latin America and the Caribbean. The leaves are eaten as a green vegetable in sub-Saharan Africa and provide a cheap and rich source of protein and Vitamins A and B. The crop is grown mostly by small-scale farmers, mainly under subsistence or semi-subsistence conditions and on low-fertility soils. It tolerates drought and can be left in the ground as a food reserve for long periods. Cassava ranks among the 15 most important agricultural commodities in developing countries with respect to value of production, and is the most important in sub-Saharan Africa.
World production in 1989, all from developing countries, was about 148 million t from about 15 million ha - some 40% of the total area in developing countries devoted to root crops. This represents an increase in production of 19% and in harvested area of 8% during the past decade. Sub-Saharan Africa accounts for approximately 42% of world production, Asia for about 37%, and Latin America and the Caribbean for 21% (75% of this from Brazil, the world's largest producer). Cassava is the most important root crop in sub-Saharan Africa, where it accounts for 70% of the harvested root crop area. It is used mainly as a fresh food, or as meal or flour after processing, and provides a major source of dietary energy for over 160 million people. Zaire and Nigeria are the largest African producers, accounting for 53% (33 million t) of production. In Asia, there are many more end uses and all the principal producing countries have starch industries. In Thailand, cassava is produced largely for export as cattle feed. In Latin America and the Caribbean, its principal use is as food, but some cassava is used to feed swine. During the 1980s, yield gains were about 10% (from 9 to 9.8 t/ha) for the developing regions as a whole, 10% for sub-Saharan Africa, 7% for Latin America and the Caribbean, and 14% for Asia. Current average yields for China, Thailand and India are 14, 15 and 19 t/ha respectively, compared with 6 to 7 t/ha in sub-Saharan Africa.
With real incomes increasing slowly or not at all in most sub-Saharan African countries, there seems likely to be a continuing demand for cassava as a human food, at least until the year 2010. Also, the crop has special significance as a food reserve. Besides the need to diminish the HCN content for safety reasons and to reduce the food preparation time required by women, cassava research in Africa should address the following principal issues: improvement of the role of cassava as a subsistence and famine relief crop; utilization of the crop's potential for income and employment generation; and the generation of marketable surpluses with significant added value to meet rising urban demand for new products. The decline in yields in sub-Saharan Africa during the 1970s was probably due to the spread of cassava mealy bug and green spider mite. The successful strategy applied during the 1980s for the biological control of mealy bug should be extended to the crop's other pests.
Cassava production in Asia has increased at an annual rate of over 5 % during the past 20 years. Thailand is the region's largest producer, with 38% of total production, and has become an important exporter of cassava chips for cattle feed. The market in Asia seems likely to remain healthy due to the demand-led diversification of cassava's end uses. There is still a need for more high-yielding clones and improved management practices in Asia.
Cassava production in Latin America and the Caribbean declined during the 1970s, especially in Brazil. During the 1980s, production remained more or less steady against a background of a 65% decrease in the area harvested. Cassava remains a small-farm crop grown in marginal areas where soil fertility and moisture limit the production of other crops. Nevertheless, cassava farmers sell a high proportion of their production. Urbanization has led to decreasing per caput consumption, but the crop is increasingly being used in animal and shrimp feeds.
In 1986 TAC considered that, for sub-Saharan Africa, the potential for further pay off from research on cassava was high and that the region's young national programmes needed continued support. It therefore recommended that the research effort be strengthened, with the emphasis on disease and pest control, the quality of leaves used as a vegetable, and the quality of roots for processing for food and industrial use. In Asia, demand was buoyant and national programmes, though relatively young, were strong. The main requirements from the CGIAR System seemed to be improved germplasm and consultation services on technical problems, especially production agronomy. With respect to Latin America and the Caribbean, the situation was considered more complex and future needs were felt to be unclear. TAC therefore recommended that in the short term the global effort be maintained but that there should be a slight shift of effort from Latin America and the Caribbean to sub-Saharan Africa.
Since 1986, studies carried out in Latin America and the Caribbean have shown that cassava is increasingly being used in animal and shrimp feeds. The rapid increase in demand for feed, coupled with the cereals deficit, suggests considerable future demand for dried cassava. In the absence of price distortions, cassava is highly competitive with cereal grains. Also, while urbanization has led to a decrease in the per caput consumption of fresh cassava, pilot studies indicate increased demand on the part of urban dwellers for new "convenience food" cassava products. Overall, the major areas for market expansion for cassava in Latin America and the Caribbean are seen to be "conserved fresh cassava", animal feed, refined flours and starch.
Approximately 27% (76 million t) of the world's potato crop is currently produced in developing countries, mainly by small-scale farmers, compared to only 15% two decades ago. Potato is a labour intensive crop. The nutrient value (including Vitamin C) of potato is high, and the crop is particularly useful as a source of energy and protein and as an infant weaning food. High yields are possible, demand is growing rapidly due to positive income elasticity of demand for the crop at low income levels, and potato has a high value as a cash crop. It ranks among the five most important food crops in developing countries with respect to gross value of production.
In 1989, developing countries accounted for about 34% of the area harvested. China is the largest producer, accounting for 40% of the 76 million t of potatoes produced in developing countries in 1989, while the rest of Asia accounted for 28%, Latin America and the Caribbean for 17%, West Asia-North Africa for 13% and sub-Saharan Africa for 2%. Yields vary from about 7 t/ha in sub-Saharan Africa to 13 t/ha in West Asia-North Africa and Latin America and the Caribbean, compared with an average of 17 t/ha in developed countries. During the 1980s, yields in the developing regions as a whole increased by 13%, from 10.9 to 12.2. t/ha.
Among the major constraints to increased production are the high costs of production, various diseases and pests, the perishability of the crop during storage, and the difficulty of developing varieties adapted to higher temperatures. As in the case of other roots and tubers, national research capacity in potato research was generally weak at the start of CGIAR activities with this commodity. Only 2% of the world's potato production is traded on international markets because of the perishability of the crop, whose high water content makes its transport over long distances risky. Quarantine regulations also restrict international trade in potato.
Potato has responded well to research, and plant breeding has already brought about significant improvements in the crop in developing countries. Virology research in the potato has advanced greatly, and the safe movement of germplasm is now a reality. The adoption of improved potato varieties is often delayed by the absence of national seed or multiplication systems. There is also a need for greater attention to the integration of potato in sustainable cropping systems.
In 1986, TAC recommended that the level of support for potato research should continue in the short to medium term, given the short history of research for tropical and subtropical regions. TAC further recommended that, in view of the stronger national programmes then beginning to emerge and the spillovers from research in developed countries, CGIAR support be reduced in the medium to long term.
Sweet potato is now widely grown as a staple food in developing countries outside tropical America, where it originated. Although sweet potato statistics are dominated by the production level of China (the world's largest sweet potato producer accounting for about 80% of production), the crop is also grown in many small countries with typically very low income levels. Sweet potato has very little research history, and outside the CGIAR only very little research is conducted on the crop. It is well adapted to warm tropical lowlands and produces relatively well under low-input conditions on good soils. Depending on variety, the crop can be harvested in three to six months. Sweet potato fits well into the multiple cropping systems of Asia. The protein content of the roots is marginally greater than that of cassava and about half that of potato and yam. Sweet potato provides large shares of calories, protein and Vitamin C, as well as Vitamin A in yellow cultivars to the diets of the poor. When eaten as a vegetable, the green leaves provide additional protein, vitamins and minerals. Production costs and labour inputs are low in terms of the yield and calories produced.
Per caput production of sweet potato has decreased during the past 20 years, and the area harvested has also diminished. As income levels have risen the consumption of sweet potato has fallen. There has also been diversification in the uses made of sweet potato. For example, in China, only about 26% of sweet potato production is now used for human consumption, as against 35% for livestock feed, 28% for industrial uses (starch and alcohol) and 11% for seed or processed snacks.
Of the 9.1 million ha of sweet potato harvested in 1989 in developing countries, Asia accounted for 91%, sub-Saharan Africa for 6%, and Latin America and the Caribbean for 3%. About 131 million t of sweet potato are produced altogether, of which 98% is from developing countries. China dominates world production, producing over 80% of developing country output, and this masks the importance of sweet potato in many small countries such as the Pacific Islands. In terms of gross value of production sweet potato ranks eighth among the major agricultural commodities in developing countries.
The demand for sweet potato is increasing in sub-Saharan Africa, where the harvested area is relatively small. Production is estimated to have increased by 25% in the 1970s and by 13% in the 1980s, and is now 2.6 times higher than that of Latin America and the Caribbean, where it declined during the 1970s but increased by 9% during the 1980s.
Although current yields in sub-Saharan Africa average only 6 t/ha, the crop's high yield potential has been demonstrated by the CGIAR System's research in that region, which has led to varieties that can produce more than 40 t/ha in four months when grown in the wet season. Similar results have been obtained from new Asian varieties. Current yields in the developing regions as a whole average around 14t/ha, with an average yield of about 18t/ha in China. Substantial potential exists for an expansion of the importance of sweet potato and its foliage as a livestock feed.
Pests and diseases, such as the sweet potato weevil, stemborer, viruses and mycoplasma-like organisms, are major production constraints. Unlike cassava, the crop cannot be stored in the ground beyond maturity, as it sprouts easily and is subject to pest attacks. Nor does it store well once lifted, although slicing and drying alleviate this problem to some extent.
In 1986 TAC considered sweet potato to be a neglected crop and recommended that the research effort be increased substantially. It recognized a need for greater collaboration between the CGIAR Centres and other institutions involved in research on the crop, such as AVRDC. The role of sweet potato in the development of new foods and food processing technologies could make it a highly valuable cash crop and employment generator in the medium to long term. In 1987, sweet potato was added to CIP's mandate, and in 1990, AVRDC decided to stop further work on sweet potato.
A crop of the warm humid and subhumid tropics, yam is a favoured food in sub-Saharan Africa, and in the Pacific and Caribbean islands. More than 90% (2.4 million ha) of the current global area under yam cultivation is in sub-Saharan Africa, where the crop accounts for about 21% of the area cultivated with root crops in the continent's root-crop belt. Nigeria alone accounts for about 70% (16 million t) of the world production of yam.
Yam is a preferred food and a food security crop in some sub-Saharan African countries. It makes major contributions to energy and protein requirements in the forest zone of West Africa, is a staple food and cash crop for millions of small-scale farmers in densely populated areas, and provides employment in transportation and sales at urban and rural markets. In West Africa, the white yam - Dioscorea rotundata - is the most highly prized type and the one that has received most attention from the CGIAR System.
The most important constraint to future production is cost. Production is carried out mainly with hand tools, and labour demands are high for planting, weeding, staking and harvesting. The cost of planting material is high: 20-30% of the previous harvest. In sub-Saharan Africa, maximum gross yields are 10 t/ha (7-8 t/ha net, after allowing for next season's planting material). Diseases threaten production and the crop's shelf life is short.
International research efforts on yam are fairly recent and small, but results are promising. Within the CGIAR System, non-stake lines capable of producing 20 t/ha have been produced and new techniques for the production of planting materials should reduce the drain on harvests. These techniques have already led to a small seed-yam production industry among yam growers in Nigeria. Research has also found ways of triggering flowering, thereby allowing plant breeding to begin.
In 1986, TAC recommended that the effort on yams be increased to a level sufficient to make a rapid impact on production and postharvest problems. TAC viewed the increased efforts devoted to yam as a short-term thrust to determine whether the apparent breakthroughs in seed propagation and the development of non-staking varieties could make the anticipated impact on production in farmers' fields.
Banana and plantain are staple food crops for millions of people in developing countries. About 90% of production takes place on small farms and is consumed locally. Only 10%, mainly from commercial plantations in Latin America and the Caribbean, enters world trade. In terms of gross value of production, banana and plantain rank fourth after rice, milk and wheat.
Banana and plantain are grown in about 120 countries. Total annual world production is estimated at over 68 million t: 24 million in sub-Saharan Africa, 26 million in Latin America and the Caribbean, and 17 million in Asia. In parts of sub-Saharan Africa and Latin America and the Caribbean, average per caput consumption is 150 to 300 grammes per day, and the crop provides 25% or more of the daily calorie intake, in addition to being a source of Vitamin B, notably B6, and potassium. Plantains are extremely rich in Vitamin A and bananas are high in ascorbic acid. During the 1980s, total production in the developing countries increased by about 15%.
The main challenges to research include breeding for resistance to Black Sigatoka disease, Fusarium Wilt (Panama disease), Bunch Top Virus and banana weevil, and the development of improved production systems.
In 1990, the CGIAR decided to extend its support for banana and plantain research beyond the humid and subhumid tropics of sub-Saharan Africa, to include Asia and Latin America and the Caribbean.
5.4.1. Chickpea
5.4.2. Cowpea
5.4.3. Broad (faba) bean
5.4.4. Lentil
5.4.5. Phaseolus bean
5.4.6. Pigeonpea
5.4.7. Soybean
The chickpea originated in West Asia. The crop is grown on small-scale farms as a food and cash crop. It is used whole, dehulled or as a flour. The immature pods, shoots and seed may be used as vegetables. In 1989, world production was 7.4 million t from 9.9 million ha, of which 98% was from developing countries. Asia accounted for 83% of production, West Asia-North Africa 12%, Latin America and the Caribbean 3% and sub-Saharan Africa 2 %. Yields have remained relatively stable over the past two decades, ranging from 0.6 to 0.7 t/ha in Asia and sub-Saharan Africa and from 0.9 to 1.1 t/ha in West Asia-North Africa and Latin America and the Caribbean.
The small-seeded desi types, which account for about 85% of world production, are grown on the Indian subcontinent, in Ethiopia and in parts of Afghanistan and Iran. The large-seeded kabuli types are grown in the Mediterranean region, Mexico, and to some extent on the Indian subcontinent. In the tropics and subtropics with summer rainfall, chickpea is grown on residual soil moisture or under irrigation. In the subtropics with winter rainfall, the crop is generally sown during the spring. It usually receives few or no inputs other than labour and seed.
Chickpea is an important dietary item in South-East Asia, India and the West Asia-North Africa region. The protein content is 19.4% of the seed. The average yield for all developing countries is about 600 kg/ha, but the Central American yield is almost twice as high, and experiments in India with limited irrigation have produced yields five times the developing world average. The area harvested globally has remained stable (around 10 million ha). In most regions, changes in yield and production reflect climatic factors.
Consumption has followed production, and it is expected that demand will increase with population in India and in West Asia-North Africa, where chickpea is liked by all income groups.
Among the major constraints to production are the low yields of local varieties, variability in yield due to environmental stresses, diseases, pests and poor crop management. CGIAR efforts have already produced significant results, notably the combination of blight resistance and frost tolerance, which has enabled winter sowing (and a potential doubling of production) in the low-elevation areas of West Asia-North Africa region. This has led to yield increases of 50 to 100%. Higher yielding, disease-and pest-resistant lines are becoming available to breeders. New, more effective strains of rhizobia have been identified, leading to considerable increases in seed yields.
In 1986 TAC recommended that the overall level of resource allocation to chickpea research be maintained, but with a shift of effort to West Asia-North Africa and East and Southern Africa (mainly Ethiopia). In the former region, research should continue to be directed at increasing productivity and stability through varietal improvement and the development of better production technology. For East and Southern Africa, TAC encouraged research directed at expanded production of the desi type in suitable agroecological areas.
Cowpea is widely grown in the warm semi-arid and subhumid regions of sub-Saharan Africa, and to a lesser extent in Asia and Latin America and the Caribbean. Production is concentrated in West Africa, where about 80% of the African crop is grown. Nigeria accounts for over 50% of the region's production. Cowpea is locally important in several other regions, particularly the Caribbean islands, Brazil, PDR Yemen, the Indian subcontinent and southeast Asia.
Cowpea is usually grown by subsistence farmers and in mixtures with maize, sorghum, millet and cassava. The dry seed is an important source of Vitamin B and protein (22% edible protein) and provides an estimated 6.5% of total protein consumed in semi-arid West Africa. Cowpea haulm is also an important source of livestock feed.
Average yields in developing countries are about 240 kg/ha. However, the best short- to medium-duration varieties so far developed can yield 2,500-3,000 kg/ha in field conditions on research stations, and short-duration varieties can achieve over 2,000 kg/ha in 60-90 days. Farm yields are limited by poor plant types, poor husbandry and the crop's susceptibility to diseases and pests.
In 1986 TAC recommended that the resource allocation to cowpea be maintained for the medium term, but with an expansion of efforts in tropical America and Asia. The factors leading to this recommendation were: the importance of cowpea as a subsistence crop in sub-Saharan Africa; its qualities of genetic diversity, fast maturation, wide environmental adaptability, resistance to drought, ability to fix nitrogen, and easy placement in cropping systems which, if exploited, could make it the most valuable of the pulses in the semi-arid to subhumid tropics; the potential value in other regions of a short-duration legume; the rapid growth occurring in production and consumption; the already promising results emerging from cowpea's short research history; and the limited capacity of national research programmes. TAC also recommended that research supported by the CGIAR System continue to concentrate on increasing yields and their stability and on improving management practices.
Faba bean is a spring crop in temperate regions and a winter crop in subtropical regions with mild winters. It is grown at high elevations in tropical and subtropical regions. Two main subgroups exist: small-seeded types, found in Egypt, Sudan and Afghanistan; and large-seeded types, found in other parts of West Asia-North Africa.
Developing countries account for almost 90% of the global production of 3.8 million t. Of the developing country share, China accounts for 69%, West Asia-North Africa 26%, and Latin America and the Caribbean 5%. The protein content is high (25% of edible portion), and faba bean is a popular food in West Asia-North Africa, though it provides only 0.9% of the region's protein. Faba bean is also a source of Vitamin B. Developing country yields of mature seed average 1,100 kg/ha, more than double that of many other pulses. It is estimated that about 20% of the crop is consumed green and is not accounted for in production estimates. Demand is likely to increase as population rises: faba bean is a preferred pulse in North Africa and parts of West Asia, and provides variety to diets elsewhere.
The constraints to production include: soil salinity in some areas; diseases; field and storage pests; the parasitic weed, Orobanche; and poor crop management.
In 1986 TAC recommended that CGIAR support for faba bean research should be phased out for the following reasons: the crop is not important globally; China, the largest producer, has a strong national programme; and there are only 1 million ha under the crop in developing countries excluding China. The CGIAR should only support the conservation and management of faba bean germplasm collections. TAC understands that ICARDA will have phased out its faba bean improvement programme by 1992, but that the faba bean collection will continue to be maintained by the Centre's genetic resources unit.
Lentil is grown in the subtropics with winter rainfall, in warm temperate regions, and in the tropics and subtropics with summer rainfall, either during cool dry seasons or at high altitudes. In no region does the crop make a large protein or calorie contribution to diet, although it is a preferred secondary food at all income levels where it is grown, and a traditional food in its centre of origin. West Asia. The vegetative parts are used for forage and green manure. Two types of equal importance are recognized, large-seeded and small-seeded.
Developing countries account for about 85 % of world production from 2.6 million ha. West Asia-North Africa and India contribute nearly 90% of that share, and several countries in Latin America and the Caribbean and in South Asia have small but locally significant production. In the drier areas of West Asia-North Africa, lentil is a key component of the traditional farming system, integrating barley, small ruminants and lentil.
The area under lentil production in the West Asia-North Africa region is 1.0 million ha and, except in Turkey, has remained more or less the same over the past 20 years. Yields are low - 500-600 kg/ha on average. A few countries have made gains in production, but these have come largely from an increase in the area harvested. Demand is expected to increase with rising population.
Constraints to production are low, unstable yields and high production costs, which cause many farmers to stop production. The harvest is labour-intensive, and a delayed harvest results in loss of seed yield from pod dehiscence and pod drop.
Good progress has been made in obtaining taller, more lodging-resistant lentil ideotypes that are suitable for mechanization. Lines have been found with greater cold tolerance and resistance to Orobanche. Yield stability in autumn-sown lentils has been enhanced through breeding for cold tolerance.
Despite the impressive progress made by ICARDA, it should be noted that the crop is of relatively minor importance in developing countries in terms of the total area under production. TAC endorsed the recommendation of ICARDA's second EPR in 1988 that continued CGIAR support for lentil improvement research beyond 1992 should be based on an in-depth assessment of the potential pay off from further research investments. Caution should be taken, however, to ensure the continued maintenance and management of the lentil germplasm collection and to continue to address the role of lentil in farming systems.
The phaseolus bean originated in tropical South America and is the most widely consumed pulse in that region. Annual growth in bean production in Latin America and the Caribbean during the past two decades was slightly greater than 1 %, well below the population growth rate of 2.4%. Beans are also important in parts of sub-Saharan Africa and Asia. They are grown predominantly by small-scale farmers in a wide range of cropping systems and a large number of agroecological zones. About 80% of the crop in Latin America and the Caribbean and in sub-Saharan Africa is intercropped, often on steep slopes and in low fertility soils. Beans are grown mainly for the mature seed. The immature pods are an important vegetable, especially in Asia, while the leaves are used as a vegetable in sub-Saharan Africa.
Phaseolus bean is a cheap source of high-quality protein, with highest consumption among the poor. It is the leading protein source in Brazil and in parts of equatorial Africa, sometimes contributing up to 30% of protein intake and 10-15% of calories. It is also a source of Vitamins A and B.
Available production data on this crop indicate that during the period 1984-86 about 6.8 million t were produced annually, in developing countries. Latin America and the Caribbean produced 4 million t annually with Brazil and Mexico accounting for about four-fifths of this. Sub-Saharan African production is largely concentrated in the highlands of East and Southern Africa, while East Asia is the centre of Asian production. Production in sub-Saharan Africa during the period 1984-86 was about 2.4 million t annually.
Yields of 500-600 kg/ha have persisted for the past 20 years, and per caput production is declining in parts of tropical South America. The crop's variations in yields and production result in considerable price fluctuations, from which the poor suffer most. Stabilization of yields through breeding and selection is difficult because of the wide variation in consumer preferences for seed colour, shape, etc. Nonetheless, CIAT has developed several improved varieties that have been widely adopted by smallholder farmers in Latin America and the Caribbean and in sub-Saharan Africa.
In 1986 TAC recommended that the level of effort on phaseolus bean be maintained, and welcomed the increasing attention being devoted to East Africa. Although work had been correctly directed towards the problem of stabilizing yields, TAC felt that more emphasis should be given to breeding for higher yield potential.
Pigeonpea is widely grown by subsistence farmers in the warm semi-arid and subhumid tropics. It is often grown on poor soils and with few inputs. It is an important food in India, and is popular in parts of East Africa and Central America. The seeds are used whole, dehulled or as a flour; and in the Caribbean and South America, immature seeds and pods are used as a vegetable. The woody stem is valuable as firewood, thatch and fencing, and the leaves are an important source of nitrogen for the soil.
World production is about 2 million t, most of which is grown in developing countries. The crop is an important source of protein (20% of mature seed) and Vitamin B. India accounts for 91% of world production, followed by sub-Saharan Africa (6%). The remainder comes from Latin America and the Caribbean and from Asia.
Average developing country yields are 700 kg/ha, but vary from 500-600 kg/ha in central and southern India, sub-Saharan Africa and Asia to 1,000-1,200 kg/ha in northern India and Central America when the crop is grown sole. The main production constraints are variable yields associated with abiotic stresses, diseases and pests and subsistence production conditions. The crop's potential for wider use in semi-arid areas with high temperatures and poor soils is considerable, making it a potential complement to phaseolus bean or chickpea in the drier and more marginal areas of East and Southern and equatorial Africa and Central America. Countries in Asia and in East and Southern Africa have shown an active interest in exploiting pigeonpea's multipurpose potential in farming systems where drought and heat tolerance are important considerations. Recently, ICRISAT achieved a major breakthrough by producing the first hybrid pigeonpea variety.
In 1986 TAC recommended that CGIAR support for pigeonpea research be increased and efforts extended to West Africa and East and Southern Africa. The crop appeared particularly adaptable to mixed cropping systems, either as an annual or perennial; and its wide range of seed colour, size and shape made it potentially more acceptable to some populations. Furthermore, the research history was short and little had yet been done outside India.
Soybean was originally domesticated in China, and is now cultivated throughout East and South-East Asia, the Americas (particularly the USA and Brazil) and to a very limited extent in sub-Saharan Africa and West Asia. In the northern hemisphere, its cultivation now extends from the tropics to 52°N.
Soybean has high protein (38%) and fat (18%) contents. The crop's main use is for oil and protein products in the food industry. The residue after oil extraction is used for flour, protein products and animal feed. Although soybean is an important food crop and an inexpensive source of protein and Vitamin B in East Asia, efforts to introduce it as a food crop elsewhere have met with limited success. However, it is gaining importance in many parts of sub-Saharan Africa. It requires special and relatively laborious processing since, when prepared in the same way as other legumes, it has an unattractive flavour and is indigestible.
About 40% of the global area harvested is in developing countries. Tropical and subtropical South America produces 49% of the developing country share (75% of this from Brazil, which has a large export trade), China 28%, temperate South America 13%, and southeast Asia 5 %. The crop provides nearly 5 % of protein consumption in China and southeast Asia. Its fat contribution to diet is 20% in Brazil, 6-7% in China, India and Thailand, and 4-5% in Indonesia. Latin America and the Caribbean produces 26 million t of soybean annually. In the past decade the region's area under soybean increased by about 1.4% per year while yields increased at 2%, reaching 1.8 t/ha (close to the world average of 1.9 t/ha). Among the major constraints limiting production in Latin America and the Caribbean are acid soils, aluminium toxicity, photoperiodism, and pests and diseases. Yields vary considerably, from 0.8 t/ha in sub-Saharan Africa to 1.8 t/ha in Latin America and the Caribbean.
Demand for oilseeds in developing countries is expected to grow at 2.9% annually until the year 2000. and production will need to increase accordingly. In sub-Saharan Africa, vegetable oil is already in short supply, and several countries of the region imported substantial quantities of both soybean cake and soybean oil during the 1980s. Most countries in Latin America and the Caribbean also have a deficit in vegetable oil. Furthermore, soybean has substantial potential as a source of livestock feed, particularly for poultry.
Soybean research has been under way for some time outside the CGIAR System, with AVRDC and INTSOY serving the needs of developing countries. Recently, good progress has been made in the development of multipurpose species. The System's own work, launched only recently, is based in sub-Saharan Africa, and has progressed well in addressing four specific problems: increasing the ability of soybean to nodulate with naturally occurring rhizobia; improving seed longevity; developing appropriate cultural and management practices for pure stands or mixed cropping systems; and resistance to pests and diseases. The principal objectives for future research in sub-Saharan Africa are to incorporate traits for promiscuous nodulation and seed longevity into otherwise agronomically superior lines, and to develop resistance to major diseases.
In 1986 TAC recommended that research support for soybean be increased, with efforts continuing to focus on sub-Saharan Africa, as the needs of Asia and Latin America and the Caribbean were being successfully met by strong national programmes. This recommendation was based on: the crop's importance, given increasing oilseed demand in sub-Saharan Africa and globally; the high level of interest in and apparent potential for the crop in sub-Saharan Africa; the high pay off from the modest research effort to date; and the excellent potential for developing solutions to some of the more important production problems in the tropics.
Oilseed crops are a large and diverse group. Soybean has already been discussed in this report under food legumes. Other important oilseeds are: coconut, groundnut, oil palm, sunflower, safflower, rapeseed, sesame, maize and olive. Cotton is also a major source of edible oil, but is grown primarily for its value as a source of natural fibre.
Oilseeds are an excellent source of protein and fat and make an ideal complement to root crops, which are predominantly carbohydrate. They are used as whole seed, vegetable oil and cake oil extraction (for animal feed), and their by-products are used for fuelwood, mulch and industrial purposes.
The production of oilseeds in the developing world kept pace with demand in the 1970s but, with the exception of soybean and oil palm, yields declined or remained stagnant during the 1980s. Total oilseed production will have to increase by an average of 3.3% annually to meet demand to the year 2000.
Besides soybean, the major tradeable oilseeds produced in the developing countries are coconut, groundnut and oil palm. Coconut and groundnut are discussed in separate sections below. Oil palm, a perennial, is a major world oil crop, grown largely on plantations in rain forest areas of southeast Asia, West Africa and Latin America and the Caribbean. Oil palm production is dynamic and highly competitive in response to the demand for vegetable oil. Intensive private- and public-sector research has led to considerable increases in yields and improved oil quality. Tissue culture has recently opened the way to raising large numbers of plantlets at low cost from elite clones. Colombia, Ecuador, Malaysia and Nigeria have strong national programmes, while international research is conducted by IRHO as well as by the private sector. In 1985 TAC considered that oil palm research needs were already being well addressed and did not require support from the CGIAR System.
The oilseeds which do not earn foreign exchange are less important. Sunflower is harvested from only 3 million ha, safflower from 1.2 million ha, and rapeseed from 7.4 million ha in the developing countries. Sesame is widely grown in the tropics and subtropics, mostly for domestic consumption. About 6.3 million ha are harvested in developing countries and India. Mexico and Venezuela have strong national research programmes for the crop. Current production of olive oil is 1726 million t, of which only 18.5 t is produced in the developing world - 97% from West Asia-North Africa where national and regional research programmes are strong. Maize oil is produced mainly in the developed world.
The coconut palm is a pan-tropical crop, grown on approximately 11.6 million ha in 82 countries. Many producing countries are small islands in the Pacific and Indian Oceans and the Caribbean. Coconut is both their primary subsistence crop and their only significant source of export earnings. There are few, if any, alternative crops which can substitute for coconut in these countries. Coconut is the major tree-crop component in several agroforestry systems throughout the world. Its wide use in home gardens is probably not reflected in official production statistics.
At least 96% of the total world production of coconut comes from smallholdings. About 70% of the crop is consumed in the producing countries. Coconut can be grown in harsh environments such as atolls, and tolerates high salinity, drought and poor soils. It plays an important role in sustaining often fragile ecosystems in island and coastal communities. Coconut is used as a source of food, drink, fuel, animal feed and shelter. It is also a cash crop, used to produce many items for sale at either the local, national or international level. The main internationally traded products are copra, coconut oil, copra meal, and desiccated coconut.
In 1986 TAC identified coconut as a priority commodity for support through international research. The CGIAR then requested TAC to explore the desirability of establishing an international research initiative on coconut, and the form such an initiative might take.
There are four major constraints to increased coconut production in developing countries: the low productivity of many coconut trees due to old age and poor nutrition; the failure of many replanting programmes; fluctuating productivity due to variable environmental conditions; and inefficient handling and processing, with low farm-gate prices to smallholders. The productivity of the crop can be increased by the use of locally adapted high-yielding, pest- and disease-tolerant varieties in replanting or new planting schemes. To increase the productivity of existing plantations it would be necessary to apply better agronomic practices including the control of diseases, insects and weeds and the use of fertilizers, and to identify and promote profitable and sustainable intercropping systems. There is a need to develop improved methods of handling and processing coconut, and to further diversify the coconut products traded.
Coconut breeding in several countries over the past 30 years has demonstrated that hybrids are capable of yielding up to 6 t copra/ha/year under favourable conditions improved with average world yields of 0.5 t/ha/year. Progress has also been made in identifying the causal agents of diseases of previously unknown etiology, such as cadang-cadang disease in the Philippines and lethal yellowing disease in the Caribbean. Nutritional studies have shown that coconut responds well to fertilizer application, particularly potassium and chloride. Intercropping and the grazing of cattle under trees have shown that the total productivity of coconut lands can be improved, without threatening the long-term sustainability of the system.
These findings suggest that a well organized and adequately funded international research effort could yield a high pay off. The long-term nature of coconut research, the history of discontinuity and lack of support in its funding, the prospects of high returns from research investments, and the likely benefits to smallholder producers, make coconut particularly suitable for an international research initiative. The priority research areas for such an initiative would be: germplasm conservation and improvement; disease and pest control; sustainability of coconut-based farming systems; post-harvest handling and processing; and the socioeconomics of coconut production. It is to be noted, however, that in a number of countries research on coconut is funded by the private sector through levies on producers.
About 18 million ha are cultivated to groundnut in the world, of which 12 million ha are in Asia (India and China have 4 million ha each) and 5 million ha are in sub-Saharan Africa. North and Central America have 0.8 million ha. Groundnut is grown under a wide range of environmental conditions in areas between 40°S and 40°N of the equator. Most of the crop is produced where average rainfall is 600 to 1,200 mm and mean daily temperatures are more than 20"C. The main use of the seed is as a source of edible oil, but the high oil (45-50%) and protein (26%) contents also make it an important food crop. As a result, large quantities are consumed in the areas of production.
As a combined oilseed and food crop, groundnut ranks second only to soybean. It is a valuable source of B Vitamins (particularly Niacin which is low in cereals), and the cake, after extraction of the oil, is a high-protein animal feed. The green haulms provide good quality fodder and can be made into hay. Groundnut is a valuable cash crop for millions of small-scale farmers in the semi-arid tropics. It generates employment on the farm and in marketing, transportation and processing. It is a valuable source of foreign exchange when exported. It also makes an important contribution to the fat content of diets in India (28%) and sub-Saharan Africa (as high as 62% in Sudan, for example), and to the protein content of diets throughout sub-Saharan Africa.
India is by far the largest producer, accounting for 39% of annual developing country production; 60% of India's production is used for oil and the rest for cattle feed. China is the second largest producer with 15%, while sub-Saharan Africa produces 21%, Latin America and the Caribbean and West Asia-North Africa 8% each, and most of the balance is produced in southeast Asia. In sub-Saharan Africa groundnut is a major food crop and only part of the produce is marketed.
The average yield for all developing countries is about 900 kg/ha of unshelled nuts. Production in India has increased in recent years, while yields in semi-arid West Africa have declined by about 5% annually. Unless the latter trend can be reversed, a major deficit will occur in that region by the year 2000.
The major constraints to production are pests, diseases, poor management, erratic rainfall, the high labour/energy inputs the crop requires, and aflatoxin production in storage. Strong national programmes exist in India, Brazil and China. The pay off from CGIAR investment in groundnut research has been high, particularly in India.
In 1986 TAC supported the current research emphasis directed towards alleviating environmental stresses and major disease and pest constraints, improving nitrogen fixation, developing lines adapted to both high and low inputs, and exploring the potential of wide crossing, which had already led to the development of very promising leaf-spot resistant material. TAC considered that the System's efforts on groundnut research had been modest and that they should be increased substantially. The factors leading to this recommendation were: the crop's important dietary contribution; its importance as a cash crop and income generator; its potential in meeting part of the global demand for vegetable oils; its secondary value as animal feed and fodder; its contribution to the sustainability of mixed cropping systems; and the belief that the crop's production constraints can be successfully solved through research. TAC supported the strengthening of efforts outside India, particularly in sub-Saharan Africa, and agreed with ICRISAT that the needs of Latin America and the Caribbean could be served through the provision of germplasm and advice. Although TAC recommended that increased efforts be devoted to soybean as well as to groundnut, the latter was considered to be of higher priority.
Many vegetables are grown in developing countries, and the kinds vary considerably from place to place, with strong social preferences dictating the choice of species used. Vegetables provide a valuable source of income to producers near large urban areas. As a group, they are high-yielding and are well adapted to small-scale operations if markets are close, and to large-scale operations as infrastructure improves and transportation and cold storage become available. All income groups need and prefer them as supplementary foods, and demand in developing countries is expected to increase by 3.4% a year throughout the 1990s.
Of the current production of 252 million t in the developing regions, Asia accounts for 70%, West Asia-North Africa for 18%, Latin America and the Caribbean for 8% and sub-Saharan Africa for 4%. Production during the past two decades has been growing at 3.2%. The four most important vegetables in terms of area harvested in the developing regions are tomato (1.6 million ha), onion (1.3 million ha), peppers (0.9 million ha) and cabbage (0.8 million ha).
Inclusion of a vegetable initiative in the CGIAR System would complete the commodity portfolio from a nutritional point of view. The major constraints are diseases and insect pests, and there is much scope for varietal improvement. Poor marketing facilities are also a constraint given the perishability of many vegetables. Modest increases in production can lead to temporary gluts, and a major research need in many areas is to extend the production period.
In 1986 TAC indicated that highest priority among new ventures within the CGIAR System should be assigned to research on vegetables. Research should be directed at the potential for increased vegetable production in both tropical and subtropical areas, with special emphasis on indigenous tropical vegetables. In 1988 TAC recommended that the CGIAR create and support an international entity which would help establish and coordinate regional collaborative vegetable research networks in Asia, sub-Saharan Africa and Latin America and the Caribbean. CGIAR support was to be limited initially to tomato, pepper, onion, and leafy green vegetables. However, TAC also recommended that studies and consultations with relevant institutions be carried out to determine the importance of other commodities such as okra and eggplant, and to identify the major constraints to production increases and marketing, as well as their research ability. The new entity would then have the flexibility to phase new research topics into its programme as necessary.
TAC further recommended that the highest priority be assigned to supporting research for tropical environments, with activities for subtropical environments to be initiated once those for tropical environments had become operational.
Two important operational considerations in TAC's deliberations were the integration of this new initiative with the System's current efforts on commodities which either are vegetables (green bean, vegetable cowpea, potato, sweet potato and soybean) or produce vegetables as byproducts (bean leaves and cassava leaves); and the complementarity of a CGIAR initiative with the work of AVRDC.
In 1990 TAC recommended that vegetables were an appropriate subject matter for inclusion in the expanded CGIAR effort, and that collaborative vegetable research networks in sub-Saharan Africa and Latin America and the Caribbean be implemented.
In low-income countries the process of development involves a net flow of savings and resources from the agricultural sector to the non-agricultural sectors. In developed countries there is a net flow (via price support or income support) from the industrial and service sectors to the agricultural sectors to ensure that the latter remain sufficiently large and strong to protect the natural resource base and ensure that food demands can always be met, even in times of political disruption. Taking this into account, the notion of sectoral self-reliance could be defined as the capacity of a nation to provide a sufficient staple food supply to all of its inhabitants either from domestic production or from the production of exportable goods to enable commercial imports to cover domestic deficits.
The original objectives of the CGIAR were stated in terms of "agricultural research", rather than research limited to food commodities only. Although the System has so far concentrated on food commodities, non-food commodities have long been recognized as important in research on production systems.
Commercial crops play an important role in many tropical farming systems in generating income. Most but not all of these crops are non-food commodities. Some are grown in large plantations for export (the plantations often employ poor, landless labourers), others are produced by small-scale farmers for sale on local markets. Historically, the CGIAR Centres have limited their germplasm enhancement activities to food crops. With the broadening of the CGIAR goal from food self-sufficiency to food self-reliance, commercial crops can be considered for CGIAR support if they contribute to income generation, especially of resource-poor farmers, in ways that enhance permanent well-being. The major crops involved include cotton, coffee, sugarcane, tea, rubber and cocoa. An overview of their importance and value of production globally and each of the regions has been provided in Tables 4.5 and 4.6. The importance of commercial crops in agricultural production in each of the regions is also well illustrated in Table 4.5 by comparing the production values of food crops with those of cash crops.
Recognizing the importance of income and employment generation, TAC has carefully considered a range of commodities that are important for cash as well as food. A potential new venture which is both an industrial crop and an oil crop is cotton. TAC recommended CGIAR support for cotton in its 1971 review of CGIAR priorities. Coffee is also an important cash crop for smallholders in many relatively high-potential areas of the developing world. While TAC has encouraged the centres to incorporate work on these crops within their research on farming systems, it has advised against embarking on a major commodity improvement programme for these crops. TAC considers the current portfolio of CGIAR activities already sufficiently broad, and has noted the lack of comparative advantage of the CGIAR for research on these crops. Crops such as coffee, cocoa, tea and rubber benefit substantially from private sector research, while cotton and fruits benefit from bilateral research programmes.
