Upland rice for highlands: new varieties and sustainable cropping systems for food security Promising prospects for the global challenges of rice production?

N. Ahmadi
CIRAD, Montpellier, France

The high plateaus of Madagascar are a typical example of rice cultivation in the highlands. Rice is the staple food in this densely populated area. Farmers traditionally grow irrigated or rainfed lowland rice wherever possible, with admirable developments in inland valleys and terraces on hillsides. But as early as the end of the 1970s, the population had to face the challenges of a growing demand for rice, the stagnation of rice yields in irrigated lowlands and the scarcity of new lowland areas which could be devoted to rice cultivation. In other respects, because of the lack of suitable varieties, they could not grow upland rice on the vast upland stretches. Indeed, upland rice growing was limited to altitudes below 1 200 m.

In the mid-1980s, CIRAD (International Cooperation Centre of Agricultural Research for Development) and FOFIFA (Centre National de Recherche Appliquée au Développement Rural) launched a research programme for the highlands, with the aim of pushing forward the frontier of upland rice-growing areas in high elevation areas of the tropics. This programme was then consolidated with research on cropping practices that ensure the sustainability of upland rice-based cropping systems.

The programme started in the high plateaus of Madagascar and soon became a crosscontinent collaborative research project, covering the Andean area of Colombia and the high altitude area of tropical China. Its results have opened up new prospects for some of the poorest farmers in intertropical areas. Thanks to the creation of a new generation of upland rice variety (with cold tolerance, short duration and adapted eating qualities), it is now possible to cultivate upland rice as high as 1 800 m above sea level. Rice cropping systems based on direct seeding on permanent plant cover without soil tillage were tested. The results are promising. As the new varieties proposed match the farmers' real needs, adoption is spectacularly fast in Madagascar as well as in the Colombian Andean areas.

The global challenges of rice production the world faces in the coming years are not very different from those faced by the population of the high plateaus of Madagascar: a growing demand for rice while the dominant irrigated model of rice production is running out of steam. In this context, upland rice - thanks to the almost unlimited cultivation areas and to the improved and sustainable cropping systems now available - offers promising prospects, complementary with the irrigated rice cropping system.

INTRODUCTION

In many intertropical regions of the world, highlands and high elevation areas (over 750 m above sea level) are characterized by rugged terrain, poor access to markets, environmental degradation and a high incidence of poverty. These areas are also often inhabited by socially and politically disadvantaged ethnic minorities. For these populations, food security remains a daily battle.

Upland rice is one of the main staple crops or staple foods in intertropical highland areas. It is grown in rainfed, naturally well-drained soils without surface water accumulation, usually without phreatic water supply and usually not bunded. Land slopes vary from 0 to over 30 percent. The most common cropping system is shifting cultivation. Farmers plant a rice crop alone or in association with other crops, such as maize, yam, beans, cassava or banana. The same field is used for 1 to 3 years until soil fertility declines and weed and pest infestations increase. They then abandon the land and return to previously abandoned farmland or start cropping on other available virgin land. The rice varieties used are of the traditional tropical japonica type, characterized by a vigorous and tall plant stature, very long panicle, low tillering ability and often long growth duration. Grain yield varies from 1 to 3 tonnes/ha depending on fallow duration and soil fertility. One variation of shifting upland rice cultivation is the pioneer cultivation where fallow is replaced by perennial vegetation. Rice is intercropped with young fruit and forest trees for 2 to 3 years (intercalary cultivation). As the trees grow, they shade a wider area and less rice is planted. In many Asian countries (Indonesia, Viet Nam, China etc.), this practice is increasingly popular under rubber trees.

Nowadays, the environmental awareness of governments leads many to encourage the permanent cultivation of upland rice in rotation with other crops. Farmers in the highlands are all the more willing to change their practices because of land shortage. But such willingness often has to face the lack of improved cropping practices ensuring the sustainability of permanent upland rice-based cropping systems.

The biophysical constraints that limit upland rice yield in highlands are numerous. The most important biotic constraint is weeds, followed by blast. Small farmers' inability to afford weed control is one of the main reasons for the shifting cropping system. Among the abiotic stresses, the major constraints are depleted soils in major elements, soil chemical disorders related to low pH (between 4 and 7) and drought caused by erratic rainfall. In high elevation areas, in northeast India, Thailand, Myanmar, Indonesia, Viet Nam, China, Central and West Africa and Latin America, upland rice also suffers from low temperatures. Damage is worse than in irrigated rice, where the water layer acts as a thermal buffer. Therefore, although irrigated rice is cultivated at altitudes above 2 000 m, upland rice is mainly confined to altitudes under 1 500 m.

During the green revolution, research programmes for upland rice initially focused on favourable environments. Breeding for yield potential attributes (plant height, tillering ability and growth duration) led to a large number of improved varieties yielding more than 5 tonnes/ha under favourable environments. Efforts were later oriented towards drought tolerance, blast resistance and tolerance to low soil fertility. Very little has been done in breeding for cold tolerance in upland rice. Similarly, little progress has been made in areas of sustainable upland rice-based cropping systems.

In the mid-1980s, CIRAD (France) and FOFIFA (Madagascar) launched a research programme for the highlands with the aim of pushing forward the frontier of upland rice in high elevation areas of humid tropics through improved cold tolerance. In the mid-1990s, this programme was consolidated with research on cropping practices that ensure the sustainability of upland rice-based cropping systems. The results of this research programme opened up new prospects for some of the poorest farmers in humid intertropical areas.

This paper is a review of the results of this research programme. It began in the high plateau region of Madagascar to soon become a cross-continent collaborative research project, producing new varieties, new cropping systems and research methodologies which perform well in low altitude areas too.

UPLAND RICE VARIETIES FOR HIGH ELEVATION AREAS

The high plateau region of Madagascar: an appropriate research site

The high plateau region of Madagascar brings together particularly favourable socio-economic and biophysical conditions for the implementation of research on cropping systems for upland rice and breeding for cold tolerance.

Farmers' high demand for upland rice due to shortage of lowlands

Rice is the staple food in the densely populated high plateaus of Madagascar (more than 200 inhabitants per km² in some areas). Farmers traditionally grow irrigated rice or rainfed lowland rice wherever possible, with admirable developments in inland valleys and terraces on hillsides. Magnificent rice terraces can be seen as high as 1 900 m. Until the mid-1970s, farming systems were mainly based on lowland rice cultivation and rice was a special and much-loved food. Per caput rice consumption (>200 kg/year) was one of the highest in the world. Faced with the saturation of wetland areas, farmers in the region then developed new farming systems based on dryland or upland crops. Attempts have been made by farmers to introduce upland rice varieties used in the traditional slash-and-burn rice-cropping system - "tavy" rice from the humid forest of the eastern coastal area of the country. But these varieties, cultivated mainly at altitudes below 750 m, were characterized by a duration which was too long for highlands above 1 200 m. Finally, in the absence of suitable upland rice varieties, farmers chose other crops, mainly maize associated with bean. Tubers and roots (cassava, sweet potato and taro) were also cultivated. But all these crops were only stopgaps and a strong demand arose for short-duration cold-tolerant upland rice varieties (Rakotoarisoa, 1996).

A very selective climate

The Vakinakaratra Prefecture (19°30' to 20°15' south latitude) hosting the research programme is the highest part of the Madagascar high plateau region. Its climate is characterized by a 6-month long rainy season from mid-October to mid-April. The months with the highest rainfall are December, January, February and March. Total rain varies from 1 300 to 2 000 mm, depending on the year and the altitude. Hailstorms are frequent at the end of the rainy season. Heavy nebulousness may reduce sunshine duration to half the duration of day length. Average hygrometry is high (around 80 percent). Mean temperatures at 1 500 m altitude vary from 17°C in October (the rice-sowing period) to 20°C during the reproductive stage. Minimum temperatures can fall below 10°C during the early vegetative stage and are below 14°C during the reproductive stage and grain-filling. The night/day thermal amplitude is high (10°-12°C) during the whole rice-growing season.

Compared to the world's other rice-growing highlands, the high plateau region of Madagascar is particularly selective with regard to temperature. Low temperatures slow down rice growth at almost all stages: panicle initiation is delayed, the grain-filling and maturation stages lengthened. Damage is worst with low temperatures at the seedling or reproductive stages; low temperatures also have a negative effect on soil fertility. Low soil biological activity inhibits nitrogen and phosphorus release (Chabanne and Razakamiaramanana, 1996a).

A breeding programme valorizing local genetic resources

Collection and introduction of local varieties from around the world

A vast programme was begun to collect local varieties of irrigated rice. Cold-tolerant varieties from altitude rice-growing areas, such as Nepal, China and Peru, or from cold temperate rice-growing areas in Japan, Korea and Bulgaria - as well as varieties screened for cold tolerance by IRRI (International Rice Research Institute, the IRCTN [International Rice Cold Tolerance Nurseries] collection), CIAT (International Centre for Tropical Agriculture) and CIRAD - were also introduced.

More than 900 locally collected or introduced varieties were first evaluated at an altitude of 1 500 m. Only 55 entries (mainly local lowland varieties) were selected. Among them, those belonging to the Latsika family had the best performances regarding sterility rate, grain yield and tolerance to sheath blight. The Latsika family belongs to the temperate japonic a group. Varieties of this family are traditionally cultivated in lowland ecosystems with altitudes above 1 800 m. In addition to these varieties, a small number of improved short-duration upland varieties developed by CIRAD and FOFIFA for medium altitude areas (750-1 000 m) were also selected. No other upland entries (local tavy varieties or introduced varieties) were able to settle their growth cycle and produce grain.

Classical and innovative breeding schemes

More than 200 crosses were performed using the Latiska family as the cold tolerance donor. Progenies of these crosses were selected with the pedigree method at an altitude of 1 500 m. In addition, using a male-sterility gene, a gene pool with a very wide genetic base was also created. It stems from the intermating of more than 50 varieties of different geographic origins. The gene pool was then used for recurrent selection for yield under low temperatures in upland ecosystems (Dechanet, Razafindrakoto and Vales, 1996).

Early multilocal evaluation through international collaboration

Once the F5 generation was reached, segregating material was evaluated over a wide range of agro-ecological environments in Madagascar and outside the country in Asia and Central Africa. In Asia, segregating material was evaluated in Nepal (Kathmandu, 1 600 m and Jumla, 2 600 m) and in the Yunnan Province of China (21°-24° north latitude, 800-1 600 m above sea level). In Central Africa, it was evaluated in the altitude swamp of Burundi. These evaluations led to the nomination of a first set of new upland varieties in 1991 (Tao Dayun et al., 1996).

Confirmation of cold tolerance through physiological assessments

One of the most important causes of physiological disorders under low temperature is the imbalance between carbon fixation and mineral nutrient uptake. Indeed, although leaves quickly warm up with sunshine and start carbon fixation through photosynthesis, low soil temperatures inhibit the rhizospherous activities.

The comparison of photo synthetic activity at different temperatures showed clear differences between the new upland rice varieties selected at 1 500 m and varieties coming from low altitude areas. In the first case, photo-synthetic activity has the highest efficiency at temperatures below 27°C, while in the second, the optimal temperatures for photosynthesis activity range from 27° to 30°C. In the same way, roots' nitrate reductase activity is less sensitive to low temperature in varieties selected at high altitude than in those coming from low altitude areas (Puard, Couchat and Lasceve, 1989).

Yield stability analysis through multilocal and pluriannual trials

A network of multilocal trials was established in the high plateau area of Madagascar in order to evaluate the yield stability of the newly created varieties. Five sites were selected according to altitude (from 1 400 to 1 600 m) and soil fertility (from rich volcanic soil to badly leached acidic and low cation exchange capacity soil).

Four years of multilocal trials led to the selection of a set of five varieties with large adaptability, yield potential above 5 tonnes/ha, growth duration varying from 145 to 166 days at 1 500 m altitude, wide variability for plant height, as well as for panicle characteristics and grain shape (Chabanne and Razakamiaramanana, 1996b).

A strong commitment to support extension activities

Early partnership with extension services

Partnership with extension services was established as early as the first days of the research project. It concerned state-run extension services as well as parastatal services involved in rural development and NGOs (non-governmental organizations) involved in agriculture and assistance to farmers. This early partnership played an important role in the effectiveness of the release of the new varieties in the high plateau region.

On-farm trials and participatory evaluation

As soon as the first set of upland cold-tolerant varieties were nominated, a vast network of on-farm varietal trials was organized. Every year, 100 to 200 on-farm trials were set up in partnership with extension services. Each trial included two to five varieties with different growth duration, plant architecture and grain shape, in order to leave enough room for the farmers' personal choice.

Set-up of a farmer's seed production system

It is well known that very often in the absence of an official seed production and distribution system, seed availability is an obstacle for the spread of new varieties. In order to avoid this situation, the research team took direct charge of basic seed production for the new upland rice varieties and encouraged the production of commercial seed (first by extension services, later by seed producer farms). The research team supervised the production of rice commercial seed by the extension services. They also organized training courses for the members of a farmer organization for seed production and distribution.

Rapid development of upland rice in the highlands of Madagascar

Thanks to the research team commitment in support of extension activities, and thanks to the fact that cold-tolerant upland rice varieties constituted an innovation which really answered farmers' needs, the development of upland rice in the high plateau area of Madagascar was spectacularly fast.

As early as 4 years after the nomination of the new varieties, a survey showed that more than 1 500 ha had already been cultivated with upland rice at altitudes above 1 250 m. The same survey indicated that more than 9 000 farmers (about 10 percent of the total in the target area) had adopted upland rice cultivation. The average upland rice surface for each farmer was about 1 500 m². Adoption was particularly high along roads and in villages that had hosted a varietal trial. Farmer-to-farmer spread of the new varieties was the most important factor in this rapid development. But the advertising and advising activities of the extension services also played an important role.

The farmers' motivation for the introduction of rice into their upland cropping systems was manifold. The three most frequent reasons given by farmers were: non-access to lowland rice-growing areas; complementary production for subsistence; and complementary production for sale. Thanks to the relatively short duration of the upland rice varieties, harvest takes place 1 to 2 months earlier than it does for lowland rice. This early harvest reduces the rice shortage period at the end of the rainy season and ensures high prices in the market. Surprisingly, some farmers also claim to have adopted upland rice for its improved eating qualities.

SOUTH-SOUTH PARTNERSHIP FOR SPREADING THE NEW TECHNOLOGY

As soon as the adoption of upland rice cultivation became a reality in the highlands of Madagascar, a new project was built with the aim of consolidating its development in Madagascar and promoting its adoption in other high-elevation tropical areas. The first two areas chosen were the Andean area of Colombia and the high altitude area of tropical China. The choice of these areas was motivated by an already existing partnership and by the fact that the populations in these areas face food security problems due to land saturation, environmental degradation or lack of access to cash income (Table 1).

In the Andean areas of Colombia, there is no rice cultivation tradition but rice has a very important place in the rural population diet, with more than 150 kg per caput per year. Rice purchase absorbs the major part of the cash income earned in coffee plantations. In China, upland rice is the principal subsistence crop for many ethnic minorities living in the mountainous area of Yunnan Province.

Introduction of upland rice in the Andean areas of Colombia

A multipartner approach

The partnership system built for the development of upland rice in the Andean area of Colombia included not only research institutions (CIRAD and CIAT), but also extension services and farmers' organizations with their "local agricultural research committees" (CIALs). This partnership system ensured taking into consideration the farmers' point of view as early as the beginning of the project.

Participatory varietal selection

A large number of lines created in Madagascar were introduced in Colombia and were directly evaluated in on-farm trials implemented by CIALs. Thanks to the completion of a large number of these participatory varietal selections, two lines were selected and nominated: Cirad 446 and Cirad 447. They proved particularly drought tolerant and resistant to rice blast. The average yield obtained in on-farm trials was 3 tonnes/ha at 1 800 m.

Taking into account post-harvest problems

The participatory evaluation took into account not only the yield but also the farmers' preferences for grain quality and post-harvest problems, especially the de-hulling question. A manual de-huller was designed and samples were produced in partnership with a local manufacturer. The initial prototype was improved through participatory evaluation. The final version enjoys a certain commercial success with 26 units sold over a few months.

A fast-track seed production and distribution system

As soon as the two new varieties were nominated, seed production was undertaken by a specialized private operator. At the same time, steps were taken to obtain the privileged Colombian statute of "improved varieties for small-scale production agriculture". This statute allows fast-track legal seed production and distribution.

When new technology meets real demand, adoption is fast

Within 5 years, more than 50 underprivileged Andean communities (3 000 families representing 17 000 people) had already adopted upland rice cultivation. This rapid and massive adoption demonstrates the feasibility of developing rice cultivation in areas with no rice-growing traditions. Convinced of the interest of developing upland rice in the Andean area of the country, the Colombia Institute for the Development of Science and Technology decided to ensure the continuation of the project.

The results obtained in Colombia have been successfully transferred to Central America. The variety Cirad 447 has been adopted and is in the course of multiplication in Equador, Costa Rica and Honduras. The manual de-huller has been introduced in Equador for evaluation and distribution by and to local users. These achievements and the fact that they have spread is a demonstration to Colombian and Central American decision-makers of poor communities' interest in rainfed upland rice. The development of upland rice cultivation is now in the hands of local NGOs. Their first technical reports are encouraging (Vales et al., 2003).

TABLE 1
Comparison of the characteristics and constraints of the three areas

Innovative breeding approach for the Chinese highlands

In China, partnership was concentrated on plant material and scientific exchanges with the Yunnan Academy of Agricultural Science (YAAS) in charge of animating a network of departmental research centres.

A long-term genetic improvement approach

In addition to the new varieties created in Madagascar, gene pools with a large genetic base worked out in Madagascar for cold tolerance and in Colombia for blast resistance have been transferred to YAAS, where the material is used in the breeding programme. In exchange, varieties of Chinese high altitude irrigated rice and low altitude rainfed upland rice have been introduced in Colombia and used as a source of cold tolerance.

Hybrid upland rice

Based on the CIRAD expertise for upland rice F1 hybrid varieties established in Brazil and on the YAAS expertise for hybrid seed production, an ambitious programme has been designed to create and distribute F1 hybrid upland rice varieties in China. The programme targets not only high altitude areas but also low altitude areas which are confronted by water scarcity due to increasing competition between the agricultural, urban and industrial uses of water resources.

This programme will use gene pools and recurrent selection to obtain male lines. Meanwhile, 200 to 300 male lines are produced every year. Combined with about ten A lines, the system allows the testing of more than 2 000 new hybrid combinations every year.

CONSOLIDATION OF UPLAND RICE DEVELOPMENT IN THE HIGHLANDS OF MADAGASCAR

Since 2000, the cultivation of upland rice is spreading spontaneously and quickly in the highlands of Madagascar. It is no longer really necessary to promote the appropriate varieties. Faced with the highland farmers' craze for upland rice, the research team makes it its responsibility to consolidate the situation through:

• the selection of a new generation of varieties that, besides cold tolerance, integrate the region's other agro-ecological constraints;

• support to local initiatives for the spread of new upland rice varieties; and

• focusing research and development activities on the design and spread of sustainable cropping practices based on the concept of "conservation agriculture".

New varieties and support to local initiative

A new generation of varieties

Thanks to the completion of a large number of participatory varietal trials taking into account the preferences of farmers and consumers, three new varieties were nominated and officially proposed for release: Fofifa 157, Fofifa 158 and Fofifa 159. The average yields obtained in on-farm trials at altitudes varying from 1 400 to 1 750 m are: 2.2, 2.5 and 2.8 tonnes/ha, respectively, with maximum yields of 5.8, 7.1 and 6.3 tonnes/ha.

Seed production

Seed production for the Cirad-Fofifa varieties by the para-public extension service, Fifamanor, and by the federation of seed-producing farmers of Vakinankaratra (VMMV) has begun, with five varieties currently proposed for release: Fofifa 133, 154, 157, 158 and 159.

Information and training

A specification and recommendation sheet for the cultivation of rainfed upland rice was distributed in the Antsirabe region to different agricultural extension organizations. Currently, the research team, in partnership with VMMV, Fifamanor, the government extension service and the NGOs, TAFA (Land and Development) and FIFATA (Association for the advancement of farmers), is working out the terms of reference for a complete technical support guide for upland rice-based cropping systems. This project has now been integrated into the body of a multipartner information system on upland rice-cropping systems and conservation agriculture in Madagascar. In addition to a yearly actualized paper version, this guide will be available for consultation on the Web.

Sustainable cropping practices based on the concept of "conservation agriculture"

It is well known that the Madagascar highlands have a poor, very fragile ecosystem. Apart from some volcanic areas, soils are depleted in major elements, the cation exchange capacity is low and the pH is highly acidic. Steep sloping lands with high runoff and lateral water movements are particularly prone to erosion. Cropping systems are based on manual or animal-drawn tillage. Major upland crops are maize, bean, soya and cassava during the rainy season, wheat, oat, potato and vegetables in the dry season. Milk production is growing, but it faces a dramatic shortage of forage. Manure is the only available source of fertilizer. Yields are very low and very sensitive to rainfall. The region is not food self-sufficient.

In order to help this traditional agriculture facing the challenges of food security, soil conservation and environmental protection, new cropping systems based on direct seeding on permanent plant cover without soil tillage developed in Brazil have been introduced and tested. In these systems, the soil is never tilled but kept permanently covered by dead or living mulch, which comes from plants in intercropping or relay-cropping systems. These plants have strong and deep root systems and can recycle nutrients from deep horizons for subsequent use by the main crops. They also have a high and fast biomass production and are able to grow in adverse conditions (such as are found in the dry season) on compacted soil or under high weed pressure. These cropping systems are not only attractive economically, but they also propose solutions for soil preservation and for recovering soil fertility.^[8]

Their transfer and adaptation to the high plateau of Madagascar started in the early 1990s, when upland rice was still absent from the area because of lack of adapted varieties. Direct-sowing experiments included the major crops of the area. These experiments were of course perennial as soil characteristics are improved gradually over 2 to 5 years. Direct-sowing cropping systems - associating maize with a leguminous plant of the Arachi, Desmodium or Trifolium genus as live plant cover, or associating soya with a perennial graminacea of the Pennisetum genus, or a continuous intra-annual succession of bean and oat - increased yield two to three times over 5 years. When compared to traditional tillage-based cropping systems, the new systems also appeared less susceptible to rainfall variability.

The evaluation of upland rice within the direct-sowing experimental site of the high plateaus started in the late 1990s when cold-tolerant and short-duration upland rice varieties became available. The experiment included upland rice-soya rotation and upland rice-oat + bean rotation. For a given crop rotation and a given fertilizer level, direct-sowing upland rice yields are two to three times better than under the traditional cropping system based on manual or animal-drawn tillage (Michellon et al., 2001).

CONCLUSIONS AND PROSPECTS

Ensuring the sustainability of upland rice-based cropping systems

The objective of pushing forward the frontier of upland rice-growing areas in high elevation regions of humid tropics was achieved through the creation of a new generation of upland rice varieties, showing cold tolerance, short duration and adapted eating qualities. The adoption rate of upland rice cultivation by farmers in the highlands is high and gaining momentum. In the Andean area of Latin America, the new varieties have even been given a nickname: RHICO (rice for hillsides with cold tolerance). In these underprivileged areas, the spread of the new upland rice varieties will undoubtedly help farmers, especially the poorest, to face food security.

But new varieties, even with very high performance, cannot ensure the sustainability of the cropping systems in the fragile and often unfertile environment of the highlands. Cropping systems, based on direct seeding on permanent plant cover without soil tillage, seem to be a promising technical answer to the challenges of soil and water conservation and environmental protection that traditional agriculture is facing in these areas. Some farmers have already adopted these new cropping systems in the high plateaus of Madagascar as well as in the low elevation areas of Madagascar and in some other developing countries in Asia, Africa and Latin America. Efforts should be maintained for this development.

In Madagascar, a new research unit focusing on "sustainable cropping systems and rice cropping" was created in 2001. Some 20 scientists from FOFIFA, CIRAD and the University of Antananarivo are working together for the improvement of the upland rice-based cropping systems through a better understanding of the biological bases of conservation agriculture following an integrated pest and crop management approach. The unit also has a capacity-building objective and hosts some six Ph.D. thesis research activities.

In Asia, the initiative of the Consortium for Unfavourable Rice Environment (CURE) to draw strategies for sustainable development of agricultural production systems in the mountain regions of the Greater Mekong Subregion (GMS) countries) constitutes the best international framework for research and development efforts.

Upland rice: a new prospect for the global challenges of rice production the world will face in coming years?

As early as the mid-1980s, the population of the high plateaus of Madagascar faced the challenges of a growing demand for rice, the stagnation of rice yields in irrigated lowlands and the scarcity of new lowland areas which could be devoted to rice cultivation. The introduction of upland rice and sustainable upland rice-based cropping systems opened up new prospects for this population and were, therefore, adopted rapidly.

The global challenges of rice production the world faces in the coming years are not very different from the ones already faced by the population of the high plateaus of Madagascar: a growing demand for rice while the dominant irrigated model of rice production is running out of steam. In order to meet demand, production should increase by about 20 percent in the next 20 years. But yields of irrigated rice are no longer increasing or are increasing very slowly, irrigated areas are not extensible, competition with non-agricultural uses of water and land is increasing, and there are conflicts with environmental concerns.

In this context, the upland rice production model - often disparaged for negative environmental effects and low, unpredictable productivity - offers very promising prospects. Indeed, on the one hand, possibilities for the extension of upland rice cultivation areas are almost unlimited: tens of millions of hectares of land favourable to upland rice still remain uncultivated in the intertropical areas of Latin America and Africa. On the other hand, during the last 30 years, research programmes have consistently improved the prospects of sustainable upland rice-based cropping systems. For example, in the Brazilian Cerrados, yields of more than 5 tonnes/ha are regularly obtained through cropping systems based on the direct sowing of upland rice on permanent plant cover.

Likewise, upland rice seems to be a promising rice production system complementary with the irrigated cropping system.

REFERENCES

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Chabanne, A. & Razakamiaramanana, M. 1996b. Comportement multilocal et pluriannuel des nouvelles variétés de riz pluvial d'altitude à Madagascar. In C. Poisson & J. Rakotoarisoa, eds. Rice for highlands. Proceedings of the International Conference on Rice for Highlands, Antananarivo, Madagascar, 29 Mar. - 5 April 1996. Montpellier, France, CIRAD. 269 pp.

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Puard, M., Couchat, P. & Lasceve, G. 1989. Etude des mécanismes d'adaptation du riz aux contraintes du milieu. Modifications anatomiques des racines. Agronomie Tropicale, 44(3): 165-171.

Rakotoarisoa, J. 1996. Caractéristiques et contraintes de la riziculture d'altitude à Madagascar. In C. Poisson & J. Rakotoarisoa, eds. Rice for highlands. Proceedings of the International Conference on Rice for Highlands, Antananarivo, Madagascar, 29 Mar. - 5 April 1996. Montpellier, France, CIRAD. 269 pp.

Tao Dayun, Fengyi, H., Guifen, Y. & Jiangyi, Y. 1996. Introduction and utilisation of CIRAD upland rice cultivars in China. In C. Poisson & J. Rakotoarisoa, eds. Rice for highlands. Proceedings of the International Conference on Rice for Highlands, Antananarivo, Madagascar, 29 Mar. - 5 April 1996. Montpellier, France, CIRAD. 269 pp.

Vales, A., Dossmann, J., Salazar, S., Munoz, C., Gomez, W., Valverde, R., Pas, O., Garcia, J. & Ortega, C. 2003. RHICO, a new rice type for confronting food insecurity in the mountains and a new option for temperate upland rice. Third International Temperate Rice Conference. Punta del Este, Uruguay, Mar. 2003.