a Head and b Database Administrator, Social Sciences Division, IRRI, Manila, Philippines
INTRODUCTION
Rice is the staple food and principal crop in humid and subhumid Asia. From the Philippines in the east to eastern India in the west, from central and southern China in the north to Indonesia in the south, rice accounts for between 30 and 50 percent of agricultural production and between 50 and 80 percent of dietary intake (Hossain and Fischer, 1995). Because of its importance in providing national food security and generating employment and incomes for the low-income sectors of society, most Asian governments regard rice as a strategic commodity. Maintaining self-sufficiency in rice production and ensuring stability in rice prices have remained important political objectives in most Asian countries (Anderson and Hayami, 1986; Thiele, 1991).
Asia has done remarkably well in terms of meeting the food needs of its growing population over the last three decades. Since the mid-1960s, rice production has increased at a rate of 2.6 percent per year, keeping pace with population growth and the income-growth-induced changes in per caput food consumption. Over four-fifths of the growth in production was due to the increase in yields, made possible through gradual replacement of traditional varieties with modern cultivars developed in rice research stations, supported by public investment for expansion of irrigation infrastructure, extension system and supply of credit facilities (Barker and Herdt, 1985; David and Otsuka, 1994; Pingali; et al., 1997; Sombilla et al., 2002a). The downward trend in real prices of rice, observed in many Asian countries since the late 1970s, has contributed to poverty alleviation by empowering the rural landless and the urban labouring class to acquire more food from the market. Nevertheless, poverty, food insecurity and malnutrition are still widespread in many low-income Asian countries. Recent World Bank estimates indicate that nearly 1.2 billion people still live off an income of less than US$1 per day and 800 million suffer from hunger (World Bank, 2000; Bender and Smith, 1997). Asia is the home of two-thirds of these food-insecure people. In developing countries over 170 million children suffer from anaemia and 140 million from vitamin A deficiency. Asia accounts for 73 and 64 percent of these numbers (Mason et al., 1999). The prevalence of malnutrition is higher in South Asia than in sub-Saharan Africa (UNDP, 2002).
The issue is whether Asia will be able to sustain favourable food balances and further improve food and nutrition security for low-income households in the early twenty-first century. This paper analyses factors governing the long-term demand-supply balances of rice in Asia, and it outlines the technological challenges faced by rice science in order to maintain the supply-demand balance.
PERSPECTIVES OF DEMAND Income effect
At low income levels, meeting energy needs is the most basic concern for an individual. Staple foods, such as starchy roots, rice, wheat and coarse grain, provide the cheapest source of energy; poor people therefore spend most of their income on such food. The choice of the staple depends on culture, as well as local production, availability and relative prices of different food items. In rice-producing regions, the extreme poor often have to make do with coarse grains and tubers, due to lack of purchasing capacity. As incomes grow, per caput rice consumption increases with consumers substituting the coarse grains and tubers with rice. But as incomes increase beyond a threshold, people can afford to have a high-cost balanced diet containing foods that provide more proteins and vitamins, such as vegetables, fruits, fish and livestock products. From that income threshold, the per caput consumption of staple grains (for Asia it is mostly rice) begins to decline.
FAO food balance sheets (Table 1) show that among Asian countries, per caput cereal consumption has declined substantially in Japan, Taiwan, the Republic of Korea, Malaysia and Thailand - all middle- and high- income industrialized countries that have passed the above-mentioned income threshold. China and Indonesia (two giant Asian nations accounting for over one-third of global rice consumption) are approaching the threshold of peak per caput consumption from which a declining trend may be expected. Myanmar, Viet Nam and Cambodia, although at low-income levels, have reached high levels of rice consumption and any further increase is unlikely. But in South Asia (except Sri Lanka) and the Philippines, 30 to 50 percent of the people live in poverty and do not have sufficient income to access the food required for a healthy productive life. With economic growth and reduced poverty, per caput rice consumption is expected to increase further in these regions, since the poor could then afford to satisfy their demand for staple food. The rate of change in per caput consumption of food staples over the next three decades will then depend on the relative strength of the upward pressure for low-income countries and of the downward pressure for middle- and high-income countries.
TABLE 1
Changes in the cereal and rice consumption
patterns in Asia, 1970-2000
|
Country |
Cereals |
Rice |
||||
|
1970 |
1980 |
2000 |
1970 |
1980 |
2000 |
|
|
Japan |
143 |
126 |
117 |
91 |
73 |
59 |
|
Korea, Rep. |
215 |
196 |
163 |
123 |
135 |
89 |
|
Malaysia |
156 |
147 |
148 |
121 |
109 |
91 |
|
Thailand |
153 |
153 |
126 |
150 |
145 |
109 |
|
China |
155 |
186 |
190 |
78 |
84 |
90 |
|
Indonesia |
124 |
154 |
205 |
100 |
122 |
151 |
|
Myanmar |
164 |
192 |
220 |
159 |
184 |
208 |
|
Cambodia |
186 |
155 |
172 |
170 |
140 |
163 |
|
Philippines |
111 |
134 |
135 |
83 |
96 |
102 |
|
Viet Nam |
174 |
158 |
185 |
157 |
133 |
170 |
|
South Asia |
155 |
143 |
161 |
74 |
65 |
78 |
Source: FAOSTAT, 2002.
Urbanization
The other force that will dampen the demand for rice is the trend of urbanization. As people move from rural to urban areas, energy needs decrease somewhat since employment tends to be mental labour as opposed to physical labour. Also, the cost of meeting non-food basic needs, such as education, healthcare, transport and recreation services, is higher in urban areas; therefore a smaller share of the family budget is available for staple food. The balance between staple and non-staple food also shifts for various reasons: the greater awareness of the importance of a balanced diet; and the widespread practice of eating away from home, due to the availability of food services and as a result of the greater participation of women in economic activities. Consequently, for the same level of income, per caput consumption of rice is generally lower in urban areas than in rural areas (Table 2). In Asia, the level of urbanization remains low, but it is projected to grow rapidly with economic development (UN, 2002) (Table 3). The demand for rice is destined to decline as an ever larger proportion of people live in urban areas.
TABLE 2
Per caput consumption of rice (kg/year),
Thailand and Bangladesh
|
Ranks in the income scale |
Thailand |
Bangladesh |
|||
|
Rural |
Semi-urban |
Urban |
Rural |
Urban |
|
|
Bottom 25% |
151 |
133 |
97 |
148 |
141 |
|
Middle 50% |
146 |
125 |
89 |
179 |
147 |
|
Top 25% |
134 |
115 |
78 |
194 |
133 |
|
Total |
146 |
125 |
83 |
175 |
142 |
Source: for Thailand, Isvilanonda et al., 1999; for Bangladesh, Bangladesh Bureau of Statistics, 1998.
TABLE 3
Projection of population residing in urban
areas, selected Asian countries (% of total population)
|
Country |
1960 |
2000 |
2010 |
2020 |
2030 |
|
Japan |
63 |
79 |
81 |
83 |
85 |
|
Korea Rep. |
28 |
82 |
87 |
89 |
91 |
|
Thailand |
13 |
20 |
22 |
27 |
33 |
|
Indonesia |
15 |
41 |
51 |
58 |
64 |
|
China |
16 |
36 |
45 |
53 |
60 |
|
India |
18 |
28 |
30 |
35 |
41 |
|
Bangladesh |
5 |
22 |
31 |
38 |
44 |
|
Asia |
21 |
38 |
43 |
49 |
54 |
Source: United Nations, 2002.
Population growth
Given the level of per caput consumption, the increase in total demand obviously depends on the rate of population growth. In the developed world, the demand for cereals as human food has been declining because most countries have achieved a stationary population. But in many Asian countries population growth continues to range from 1.5 to over 3.0 percent per year. The exceptions are Japan, China, Republic of Korea, Thailand and Sri Lanka, where the rate of population growth is less than 1 percent per year. However, given the increasing growing economic prosperity, the growth of population will continue to decrease in these countries - as was the case of todays developed countries during their early stages of development.
According to UN projections, population growth in Asia over the 2000-2030 period will fall to 0.9 percent per year, compared to the 1.8 percent per year recorded in the period 1970-2000. The annual growth rate is expected to reach 0.6 percent by 2025-2030, compared to the current rate of 1.2 percent. The annual absolute increase in the number of people in Asia will reach 30 million three decades from now, compared to the current 46 million. Ironically, it is in the poverty-stricken regions, where per caput rice consumption is expected to increase, that population growth will be faster (Figure 1). The 2001 population census in India, for example, reported that the population grew at a rate of 1.8 percent per year during 1991-2001; the growth rate declined only marginally compared to 1981-1991; and the increase was substantially higher in the poverty-stricken eastern and northern states compared to the relatively prosperous southern and western states.
FIGURE 1
Projected increase in population from 2000 to
2030

Source: United Nations, 2002.
Projected growth of demand
The International Food Policy Research Institute (IFPRI) developed a Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) for long-term projections of demand supply balances for major food items (Rosegrant et al., 1995). It specifies a set of country or regional submodels, each with a particular structure within which supply, demand and prices for the commodities are determined. The country- or region-specific submodels are linked through trade, a specification that highlights the interdependence of countries and commodities in the world agricultural economy. The model uses a system of supply and demand elasticity, derived from other studies, incorporated into a series of linear and nonlinear equations, to approximate the underlying production and demand functions. Sombilla et al. (2002b) ran a revised model incorporating the most recent UN population projections and the slower economic growth of east and Southeast Asia experienced after the Asian financial crisis, compared with the original study of the 2020 projections of food supply and demand balances. The results show that the demand for rice will grow at a rate of just 1.0 percent per year, implying an increase of 32 percent over the 2002-2030 period (Table 4). The increase in demand is substantially lower than the historical growth of rice production of 2.6 percent per year over 1967-2000. The reduced growth of demand is mainly on account of the situation in East Asia, where it is projected to increase at a rate of only 0.38 percent per year. In South Asia, demand is expected to increase at a rate of 1.5 percent per year, requiring an additional 52 percent increase in rice supplies over the 2003-2030 period to keep up with demand.
TABLE 4
Projected growth of demand for rice in Asian
regions
|
Region |
1997 |
2025 |
% increase |
Annual growth |
Annual growth |
|
East Asia |
138.7 |
154.0 |
11.0 |
0.38 |
0.60 |
|
Southeast Asia |
82.4 |
114.7 |
39.2 |
1.19 |
1.17 |
|
South Asia |
108.4 |
165.8 |
53.0 |
1.53 |
1.40 |
|
Asia |
329.6 |
434.1 |
31.7 |
1.00 |
1.02 |
Source: IFPRI, updated IMPACT model in Sombilla et al., 2002.
An important point to note in this context is that with economic prosperity, the affluent consumer may not increase rice intake but will be willing to pay higher prices for a given quality of rice. So, although the demand in terms of quantity may slacken, the market for quality rice will expand as the middle classes increase (as demonstrated by the experiences of Japan - Figure 2 - and Republic of Korea). Thus, composition of demand will change in favour of high quality rice, with important implications for future rice breeding and production strategy.
FIGURE 2
Changes in rice consumption in Japanese
non-farm household (per caput income data)

Source: Comprehensive Time Series Report on the Family Income and Expenditure Survey 1947-86.
PERSPECTIVES OF PRODUCTION AND TRADE
The impressive growth of rice production over the last three decades has generated a sense of complacency regarding Asias ability to meet the growing demand for rice. Recent trends (Figure 3) in the growth of rice production lead to concern regarding the sustainability of past achievements. The growth in rice yield has slackened considerably since the late 1980s, and has failed to outpace population growth in a large number of countries (Table 5). Several factors suggest that this is an indication of the beginning of a long-term trend rather than a cyclical downswing.
FIGURE 3
Growth in rice production and productivity:
pre- and post-green revolution period

a Growth rate estimated by fitting semi-logarithmic trend line on time series data.
Source: FAO electronic database, 1998.
TABLE 5
Trends in rice yield and production in the last
decade compared to the first two decades of the green revolution, selected Asian
countries
|
Country |
Growth rate in production |
Growth in yield |
||
|
1970-1990 |
1990-2000 |
1970-1990 |
1990-2000 |
|
|
Korea Rep. |
1.82 |
0.06 |
1.57 |
1.24 |
|
China |
2.67 |
0.03 |
3.16 |
0.97 |
|
Indonesia |
4.71 |
0.86 |
3.35 |
-0.06 |
|
Philippines |
3.33 |
2.38 |
3.49 |
0.60 |
|
Viet Nam |
3.23 |
4.66 |
2.13 |
2.69 |
|
Thailand |
2.24 |
3.40 |
0.57 |
2.21 |
|
India |
2.93 |
1.51 |
2.36 |
1.30 |
|
Bangladesh |
2.52 |
3.49 |
2.12 |
2.85 |
Note: Growth rate estimated by fitting semi-logarithmic trend lines to the time series data.
Source: FAOSTAT, 2003.
Growing scarcity of agricultural inputs
Economic prosperity in Asia is a crucial factor affecting the availability of labour, water and land for rice cultivation. The competing demand for these inputs from other economic activities affects their relative scarcity and prices, as well as changing the relative profitability depending on the intensity of use of these inputs in a particular activity.
Labour and wage rate
Economic growth brings dramatic changes in the structure of employment, adoption of labour-saving technology and increase in labour productivity. As the opportunities for more remunerative employment increase elsewhere, workers move out of low-productivity, low-wage food production activities. Although the agricultural sector responds to the problem by adopting labour-saving technologies, as demonstrated by the experience of Japan, Republic of Korea and Thailand, it cannot compete with the manufacturing and service sectors. Productivity differences therefore continue to grow alongside economic prosperity. In the Republic of Korea, for example, labour productivity in manufacturing increased 4.3 times during the 1966-1990 period, compared to an increase of just 1.2 times in the agricultural sector. The total agricultural labour force increased from 4.5 to 6.1 million people between 1966 and 1975; it then began to decline in absolute terms, reaching 2.4 million by 2000.
Labour scarcity is reflected in the price of labour: the wage rate. In East and Southeast Asia (where per caput income has grown by more than 5 percent per year), the real wage rate increased by 170% between 1970 and 1990. In South Asia, where economic growth has been moderate, the real wage rate increased by only 50 percent (World Bank, 1995). Compared to Bangladesh, the cost of agricultural labour in 2000 was more than 30 times higher in Korea and 75 times higher in Japan.
Availability of water
Water resource development has been the key to increasing rice production in countries where land is a scarce factor of production. Water has generally been regarded as an abundant resource for humid Asia. But with a rapidly increasing population, per caput availability of water has been declining and water is used for irrigation to meet the growing food needs. As a result, the perception of abundance of water has been changing in many Asian countries. The per caput availability of water resources has declined by 40 to 60 percent in most Asian countries over the 1955-1990 period (Fredericksen et al., 1993; Feder and Keck, 1996). By common convention, countries are defined as water-stressed when availability is between 1 000 and 1 700 m3 per caput. Projections based on constant availability of water and increasing population suggest that China, Thailand, India, Sri Lanka, Pakistan and the Republic of Korea are expected to reach near stress levels by 2025.
The scope of further conversion of rainfed land to irrigated land (the major source of past growth in rice production) is also becoming limited (Rosegrant and Svendsen, 1993). The cost of irrigation has increased substantially, as easy options for irrigation development have already been exploited. Also, there is increasing environmental concern regarding the adverse effects of irrigation and flood control projects on waterlogging, salinity, fish production and the quality of groundwater. There has already been a drastic decline in investment for the development and maintenance of large-scale irrigation projects in many Asian countries.
Competing demand for land
Economic prosperity and industrial progress is leading to rapid urbanization and a high concentration of people in a few large cities. An important implication of growing urbanization is that part of the fertile agricultural land has to be used to meet the demand for housing, factories and roads. Furthermore, with urbanization and the associated changes in eating habits, the markets for vegetables, fruits and livestock products will grow stronger. There will be economic pressure to reduce the area under rice cultivation to accommodate these relatively high-value crops.
Future growth in rice production must occur on less land, utilizing less labour and less water. The downward pressure of input availability on the growth of supply is thus obvious. Rice yield and labour and water productivity must grow at a faster rate than the increase in the demand for rice, to maintain a favourable demand-supply balance.
Sustaining farmers incentives in rice cultivation
Despite the impressive increase in land productivity, it has been difficult for the fast-growing Asian countries to sustain producers interest in rice farming. Given that rice farming is a highly labour-intensive activity, the growing scarcity of labour and higher wages pushed up the cost of rice production, reducing profits and farmers incomes. It is not only labourers who are tempted to move to non-farm urban and rural occupations; even small-scale rice farmers find it more attractive to leave rice farming and join the non-farm labour force.
Competitiveness in rice farming should be maintained through:
improved farm management practices increasing efficiency in the use of non-land inputs and increasing total factor productivity;
increased use of capital to replace labour through the mechanization of farming operations so that labour productivity can be continually raised when no further increase in land productivity is possible; and
using the price mechanism to transfer income from the relatively well-off rice consumers to the low-income rice producers, in order to maintain a balance between farmers incomes and the earnings of the urban labour force.
In spite of these policies, sustaining farmers interest in rice cultivation has remained a major challenge to the fast-growing Asian countries. In regions where the yield level is high (e.g. in Japan and the Republic of Korea), the scope of increasing profitability through efficient use of inputs has almost been exhausted. As labour accounts for only one-quarter of the cost of rice production (Yap, 1992), the substitution of capital for labour has had only a limited impact on increasing farm incomes, especially when farm size cannot be increased due to population pressure. Land prices continue to increase due to high population pressure and the resulting demand on land for housing, commercial use and infrastructure development. In the Republic of Korea, rural wage rates and land prices increased at a rate of 18 percent per year during the 1970-1990 period, while machinery and fertilizer prices increased at a rate of 7 percent (Park, 1993).
As the cost of rice cultivation continued to increase due to the rising cost of labour and land, Japan and the Republic of Korea continually increased rice prices and farm subsidies in order to maintain the balance between rural and urban household incomes. The protection of the domestic rice industry encouraged high-cost domestic production. In the late 1990s, the cost of producing rice in Japan was about 25 times higher than in Thailand and Viet Nam (Table 7). It is thus clear that, with economic development, the comparative advantage in rice production shifts to the low-income countries and low-income geographical regions within a country.
TABLE 6
Long-term trend in wages rates(US$/day),
selected Asian countries, 2000
|
Country |
1961 |
1971 |
1981 |
1991 |
2000 |
|
Bangladesh |
0.46 |
0.44 |
0.86 |
1.39 |
1.27 |
|
Philippines |
1.39 |
0.59 |
1.51 |
2.16 |
3.84 |
|
Korea Rep. |
0.82 |
1.86 |
10.84 |
32.59 |
38.84a |
|
Japan |
1.22 |
8.19 |
24.16 |
51.93 |
84.35 |
a 1996 figure. Source: IRRI, 2002.
TABLE 7
Rice yield and unit cost of rice production,
selected countries
|
Country |
Ecosystem |
Year |
Rice yield |
Unit cost |
|
Thailand |
Irrigated |
2000 |
4.20 |
70 |
|
Rainfed |
2000 |
2.24 |
103 |
|
|
India |
Irrigated |
1995-96 |
5.16 |
88 |
|
Rainfed |
1995-97 |
2.26 |
115 |
|
|
Viet Nam |
Irrigated |
2000 |
4.18 |
79 |
|
Burkina Faso |
Rainfed |
1987-1990 |
2.50 |
288 |
|
Guyana |
Irrigated |
1998-2000 |
4.00 |
405 |
|
USA |
Irrigated |
2001 |
7.04 |
331 |
|
Japan |
Irrigated |
1999 |
6.41 |
2 290 |
|
Bangladesh |
Irrigated |
2000 |
4.97 |
129 |
|
Rainfed |
2000 |
1.96 |
145 |
|
|
Philippines |
Irrigated |
1999-2000 |
2.96 |
176 |
|
Korea, Rep. |
Irrigated |
1999 |
6.60 |
868 |
Source: IRRI, World Rice Statistics database and Farm Household Survey.
The implementations of the GATT Uruguay Round agreements may further dampen incentives for rice production, particularly in the middle- and high-income countries (Pingali et al., 1997). They will not be able to compete with the low-income economies of Asia where the wage rate and the opportunity cost of family labour is low, or with large land-surplus countries in the developed world (e.g. Australia, USA and Italy) who reap economies of scale because of the large size of rice farms. If the domestic market is opened up for competition, the price of rice will decline substantially, providing incentives to consumers to go for imported food staples, forcing farmers to abandon rice cultivation in favour of more lucrative economic activities.
To gain competitive strength in the face of liberalization of the rice trade, tiny holdings can consolidate into large-scale farms, as rural households migrate to urban areas leaving their land behind. Smart farming in large-scale holdings (as currently practised in the developed world) and the vertical integration of the rice industry (production, processing and marketing managed by the same farm) may contribute to more efficient utilization of large-scale machinery and a reduction in the number of part-time farmers currently tied up in the supervision of numerous tiny rice farms. The main constraint to consolidation of holdings in Asia is, however, the exorbitant land prices that prohibit the development of an active land market. At existing land prices, the rate of return in rice farming from investment on land is substantially lower than the return on investment in other enterprises. Therefore, Asia cannot expect consolidation of holdings on the scale seen in North America and Europe during the early stages of development.
Achieving food security through trade
The developed countries - North America, Europe and Australia - have sufficient natural resources to produce enough food for the world. Pressure on the natural resources of the densely populated countries in Asia could be reduced if developed countries exploited their unused capacity to produce surplus food destined to meet the deficit in countries where natural resources are limited.
The international trade of cereals - the movement of surplus grains from developed to developing countries through the market mechanism - may offer only a partial solution to the mismatch of the demand-supply balances between the developed and the developing regions of the world (Hossain, 2001). Farmers in developed countries may expect an expansion of the wheat and corn market (to be used as livestock feed given the fast-growing demand for livestock products); a similar expansion may also be seen in the developing world, but only in middle-income countries that can afford to pay for such transactions. The growth of the export market for staple food in low-income countries will remain limited due to scarcity of foreign exchange to pay for commercial transactions.
In low-income countries, the production of staple food is the major source of employment and income for the rural households; the growth in production and productivity of staple food within the country is therefore considered a better development strategy than importing food - given the sociopolitical compulsion of generating employment and income for small farmers and the landless, and improving their purchasing capacity over time. Importing staple food in low-income labour-surplus countries means importing unemployment or foregoing the opportunity of reducing under-employment. Meeting the demand-supply gap through further improvement in the productivity within national boundaries, rather than through participation in the world market, may be an appropriate strategy for addressing the problem of food insecurity and poverty.
POTENTIAL RICE TECHNOLOGIES
Irrigated ecosystem
An important factor behind the recent slowdown in the growth of rice production is the closing of the yield gap in irrigated rice cultivation. The increase in rice yield in the past originated mainly from: the gradual adoption of modern varieties on the existing irrigated land; and public and private investment for expansion of irrigation area to support the diffusion of modern varieties and improved farming practices. The success of the green revolution has been mostly in the irrigated ecosystem where the last three decades saw yields increase from 3.0 to 5.8 t/ha (Figure 4). But yield growth has remained moderate in rainfed systems. Almost the entire irrigated land has already been covered with modern varieties, and the best farmers yields are already approaching the potential that scientists are currently able to attain in that particular environment. With intensive monoculture of rice in the irrigated systems and heavy use of industrial chemicals, natural resources are under stress (Cassman and Pingali, 1995; Pingali et al., 1997). Although the yield potential of modern varieties is about 10 t/ha (Khush, 1995), in the humid tropics the maximum achievable yield at farmer level is about 6.0 t/ha because of: increased pest pressure; frequent cloudy days with below optimal sunshine; and susceptibility to floods, droughts and strong winds (Hossain, 1997). In regions with good irrigation infrastructure, this potential yield level is soon to be reached.
FIGURE 4
Trends in rice yield for irrigated and rainfed
ecosystems, 1967-1996

Source: Hossain and Pingali, 1998.
There are technologies in the pipeline that may help raise land productivity and input-use efficiency in the irrigated ecosystem, thereby contributing to a further increase in rice supplies (Khush, 1995). In 1989, IRRI began to design a new plant type (NPT), with the aim of growing an irrigated rice crop with 20 to 25 percent higher yield. It is designed to reduce the number of unproductive tillers, and to increase photosynthesis efficiency through erect and thick leaves and fewer larger panicles. Field evaluation of the early breeding lines detected various problems:
unfilled grains due to the use of javanica parents unsuitable for the humid tropics;
susceptibility to stem borers due to thick and sturdy stems; and
consumer preference which demanded that the grain types be changed from bold to slender.
Some of those problems have already been resolved. Two NPT lines with good grain quality suitable for the temperate zones have been released in China. Advanced NPT lines suitable for the tropics have been sent for trials under the International Network for Genetic Evaluation of Rice (INGER) to evaluate their suitability for different countries. A large number of lines have been shared with national agricultural research systems (NARS) partners for use as donors in their breeding programmes. Nevertheless, it may take quite some time for this technology to reach the rice farmers; the adoption of NPT-derived varieties is not expected to make a significant impact on increasing yield for the irrigated ecosystem until 2005 (Virk, 2002).
Another technology within reach of farmers is hybrid rice for the tropics (Virmani, 1994). Hybrids have a yield advantage of 15 to 20 percent over the currently inbred high-yielding varieties. Rice hybrids were originally developed in China where the increase in rice yield between 1975 and 1990 was largely due to the diffusion of these varieties in 50 percent of the rice area. The Chinese hybrids, however, are not suitable for the tropical climate in South and Southeast Asia. IRRI scientists have already developed suitable hybrid lines for the tropics which are now being used by scientists in a large number of countries to develop varieties suitable for local conditions. However, their adoption has been slow because of the low profits compared to inbred varieties (mostly due to inferior grain quality and low market prices) (Janaiah et al., 2002). Researchers are now addressing the problem by using parents and restorer lines of improved quality. The main constraint to the rapid expansion of hybrid rice among small farmers might be the development of infrastructure for the production and distribution of seeds. Farmers will need to buy seeds every season - an unconventional practice for most small and marginal farmers in Asia.
Even if NPT and hybrid rice are fully adopted by farmers in the irrigated ecosystem, yield potential will be increased by only 35 percent. For middle and high-income countries, this may not be sufficient to compensate for the rising costs of inputs, and the technology may therefore not be adopted by farmers. These technological advancements are more likely to appeal to farmers in the irrigated ecosystem in low-income countries. Assuming that 30 percent of the rice area is under the irrigated ecosystem in the low-income countries of Asia, full adoption of these technologies over the next 30 years would contribute to a further 11 percent increase in rice production, leaving a substantial gap in the balance between rice supply and demand.
Rainfed systems
The potential for raising yield in the rainfed ecosystem is still vast, as current yield is only about 2.2 t/ha. In nearly 60 percent of the land in tropical Asia, rice is grown under rainfed conditions. Indeed, this ecosystem is the dominant one in the low-income countries of Asia, where the demand for rice is projected to remain strong. If rice science succeeds in developing appropriate technologies, this ecosystem will make a major contribution to future growth in rice production.
Rainfed ecosystems are subjected to the vagaries of nature, such as droughts, floods, typhoons and erratic monsoons. Many rainfed areas also suffer from problem soils. Traditional low-yielding varieties have developed traits through centuries of evolution enabling them to withstand temporary submergence and prolonged droughts that cause large year-to-year fluctuations in yield for this ecosystem. Rice scientists have so far had limited success in identifying these traits and incorporating them in high-yielding modern cultivars (Zeigler and Puckridge, 1995). Where rainfall is unreliable and drainage is poor, farmers still grow traditional varieties and use fertilizers in suboptimal amounts in modern varieties, due to the uncertainty of returns from investments. This is the main factor behind the low yield and large yield gap seen in rainfed ecosystems.
There have been substantial improvements in recent years in developing short-duration rice varieties that help farmers escape floods or droughts in rainfed systems but without sacrificing much yield. For example, in the flood-prone Mekong River Delta in South Viet Nam, farmers now grow two short-duration high-yielding varieties during the autumn-spring and spring-summer seasons, keeping the land fallow during the period of deep flooding - as opposed to the traditional practice of growing one long-duration low-yielding and risky deep-water rice during the year. The change in the cropping system has been the major contributor to the substantial growth in rice production in Viet Nam since the late 1980s. In other countries the availability of shorter-duration varieties allows farmers to harvest rice early and establish a non-rice crop using the residual moistures, thereby promoting crop diversification, maintaining soil health and increasing farmers incomes.
The revolution in the science of molecular biology has increased the probability of research success in developing appropriate technologies for rainfed environments (Hossain et al., 2000). Structural and functional genomics help identify important genes and their association with agronomic traits. The rice breeders have begun to utilize marker-assisted selection techniques to expedite breeding cycles and improve the efficiency of breeding. Genetic engineering has already demonstrated the usefulness of introducing valuable traits in rice through transformation, that conventional plant breeding approaches have not been able to introduce. There is an opportunity to address health-related problems (e.g. micronutrient-deficiency-induced malnutrition) by breeding rices rich in vitamin A, iron and zinc (Buis and Hunt, 1999). However, to reach the poor, rice biotechnology research must address the problems of abiotic stresses, grain quality and human nutrition - problems that are predominantly found in unfavourable rice-growing environments and in regions in marginal lands.
If rice research succeeds in incorporating traits that help withstand abiotic stresses, or improved systems management helps escape these stresses, modern varieties will be adopted more extensively in the rainfed system. Yield stability will thus increase and the risks in rice cultivation will be reduced, inducing farmers to apply inputs in optimal amounts.
Whether or not biotechnology research will ultimately contribute to attaining and sustaining food and nutrition security, depends on:
the investment in biotechnology research in public sector institutions;
how national governments and the international rice research community address the issues of patenting and intellectual property rights; and
the promotion of a sociopolitical environment for impartial assessment of the benefits and risks of biotechnology.
Given the limited effective demands, the private sector may have little incentive to invest in the development of products for small and marginal farmers and for unfavourable environments. Fortunately in Asia, some large and prosperous countries (Japan, Republic of Korea, China, India, Singapore and Malaysia) have come forward to invest substantially in the development of biotechnology research facilities (Hossain et al., 2000). The International Rice Research Institute (IRRI) has been working to improve biotech research capacity in NARS through its Asian Rice Biotechnology Network (ARBN). The research outputs emanating from these efforts may remain in the public domain or may be available to low-income farmers at affordable prices. Many of the useful genes and promoters already patented are owned by private sector companies, whose intellectual property rights needs to be protected. Successful technology transfer would require the enactment of biosafety regulations for conducting adaptation trials, as well as the enforcement of provisions for intellectual property rights.
TECHNOLOGICAL CHALLENGES
The challenge to the scientific community is how to help maintain a continuous increase in food supplies despite limited natural resources and declining arable land and water supplies, in a manner that protects the soil, water and biotic resource base from which all food must come. In deciding what research issues should be given priority for a given region or a country, scientists should take account of the level of economic development and the state of exploitation of the natural resources. The Asian rice economies may be classified into three distinct groups for this purpose.
At one end are the economically prosperous countries and regions (Japan, Republic of Korea and Taiwan Province of China) with the capacity to procure rice from the world market when there is a deficit. They have already heavily exploited their land and water resources, but because of the impressive growth in both income and food grain production in the past, the energy needs of the population have already been met and the danger of further exploitation of natural resources through intensification is almost over. The per caput consumption of rice has been declining and the population growth rate has reached low levels: sustaining a high rate of growth in rice productivity is no longer a concern. The priority is to pursue agricultural mechanization and precision farming in order to increase labour productivity and make more efficient use of other inputs. The cost of producing rice is very high compared to the rice exporters in the world market; even a substantial increase in rice yield through new plant types or hybrid rice would not enable them to produce surplus for rice-deficient countries and to compete in the world market. As land and labour generate higher returns in non-rice activities, rice cultivation will gradually decline with a growing trend in the liberalization of agricultural markets.
The sustainability of rice farming depends on the continuation of government policy to maintain high prices in the domestic market. Technologies with higher yields will provide little benefit to these economies. As per caput rice consumption decreases, more riceland is kept fallow with the adoption of higher-yielding varieties; this in turn leads to an increase in governments fiscal burden on account of agricultural subsidies. If governments liberalize the rice trade and expose farmers to international competition, even a 50 percent increase in yield may not be enough to compensate for the drop in prices in the domestic market and help sustain farmers incentives in rice cultivation.
Consumers in these countries are increasingly concerned about food safety and the nutritional quality of rice. They are willing to pay higher prices for quality, including organically produced rice. The target for rice research in high-income countries should therefore be: reduction of dependence on agrochemicals (environment-friendly rice); resistance of modern cultivars to newly emerging insects and disease pressures; the quality of the natural resources; improved grain quality; and post-harvest and food processing technologies capable of increasing the value added from the same yield.
At the other end of the scale are the land-scarce low-income countries of South Asia and the Philippines, Indonesian Java and North Viet Nam in Southeast Asia. Most of the land in these countries is already allocated to growing cereal grains, yet they are unable to meet the energy requirements of the people. A major portion of the land is poorly drained and unsuitable for other high-valued crops during the monsoon season. Rice farming labour cannot be easily diverted to other economic activities due to the small size and slow growth of the non-farm sector. The population is still growing at a rate of almost 1.5 to 2.4 percent per year, and self-sufficiency in rice (where it has been achieved) is partly due to the lack of purchasing capacity of a large section of the people living in poverty (e.g. in India). The real challenge for the rice research community over the next few decades is to help this region achieve and sustain food security. An annual increase in rice productivity of 2 to 3 percent must be achieved with less land to allow crop diversification, while at the same time increasing the productivity of labour and maintaining the quality of natural resources.
Rice research for these countries should focus on reducing the existing large yield gap in rainfed ecosystems, and on shifting the yield potential for irrigated land so as to enhance productivity. New plant type and hybrid rice technologies are in great demand from farmers who have already achieved high yields. Research for the rainfed system must focus on understanding the processes and mechanisms that give traditional cultivars their capacity to withstand abiotic stresses, using this knowledge to develop high-yielding cultivars with more stable yields. Crop management research requires a systems approach to explore how non-rice crops can fit into the rice-based system to increase and stabilize farmers income. An effective partnership between national and international scientists will be required to understand the problems of variable ecosystems and plant interactions for exploitation of the resource base in carefully selected key sites representing large geographic areas. Modern biotechnology tools for incorporating difficult traits into improved varieties will be highly relevant for these countries.
The third and middle group includes countries with substantial excess capacity in rice production, such as Myanmar, Thailand, Cambodia and Malaysia. Exploitation of this potential depends more on favourable prices in the world rice market and governments willingness and capacity to invest in the development of the marketing infrastructure, than on the success of rice research in pushing the yield frontier. The challenge for rice technology development in this region should be: improvement in grain quality to empower farmers to capture the growing market for quality rice; durable host-plant resistance to major abiotic stresses using biotechnology tools; development of environment-friendly and cost-effective methods of controlling weeds (e.g. allelopathy) so that farmers could adopt labour- and water-saving methods of crop establishment (e.g. direct seeding); and precision farming methods for encouraging the establishment of low-cost large-scale farming.
CONCLUSION
Maintaining a favourable rice supply-demand balance in Asia in the future depends largely on the exploitation of the production capacity of the rainfed systems in low-income countries. Research problems in less favourable rainfed ecosystems are more challenging and the probability of research success is less certain than for the relatively homogeneous irrigated ecosystem for which substantial progress has already been made. To make headway in the development of appropriate technologies for resource-poor environments will require mobilizing the best of science and the best of scientists in national agricultural research systems, international centres and advanced institutions through partnership research. The relevance and effectiveness of research depend on: close collaboration among research partners; selection of key sites; the mechanism of partnership research; and research environments that encourage scientists to work on problems with uncertain outcome. Recent advances in molecular biology, systems models and Geographic Information Systems will hopefully encourage scientists to put more effort into addressing the more difficult and complex problems of rainfed rice cultivation than has been done to date.
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