World Conference on Horticultural Research - 17-20 June 1998 in Rome, Italy
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S.C.S. Tsou and S. Shanmugasundaram
Director General and Director/ International Cooperation Program,
or/ International Cooperation Program,
AVRDC, P.O. Box 42, Shanhua,Tainan, Taiwan 741.


More than 2 billion people worldwide, most of them living in poorer countries in Asia, Africa and Latin America, are malnourished and have micronutrient deficiency. Vitamin A, iron and iodine deficiency in the diet is predominant and it exceeds protein-calorie malnutrition. Micronutrient deficiencies in the diet result in improper physical and mental development in children as well as adults which is responsible for lower productivity and inferior quality of life. Population density and population growth in most developing countries are high. Although these countries are predominantly agrarian in nature, the farm size is generally small, especially in Asia. Therefore, intensive cultivation and improved productivity per unit area is the key to rural economic and social development.

Vegetables are labour-intensive crops. Processing of vegetable crops, for value addition, creates additional job opportunities, especially for women in the rural sector. Vegetables and vegetable legumes are rich in vitamins, minerals, plant proteins and fibre which complement well with cereals in enhancing the nutritive value for a balanced diet. In spite of all the above advantages, resources allocated for research on vegetables have been limited. These limited resources should be used efficiently to acc limited resources should be used efficiently to accomplish priority objectives. AVRDC's strategy to best achieve the above goal is to consolidate the National Agricultural Research Systems (NARS) into a collaborative mode so that they can cooperate with each other for mutual benefit. Therefore, the basic strategies of the AVRDC-catalysed vegetable research networks are as follows:

1) Learn by exchanging mutual experiences
2) Share available resources to develop a critical mass at the subregional level
3) International centres and regional associations such as APAARI, can serve as catalysts and partners to enrich collaboration
4) Focus research efforts on issues common to countries in the region and technologies which have better chances of making an impact.

The essential ingredients for the success of the networks are:

a) In planning, AVRDC is careful in choosing, in consultation with partners in the region, issues that are practical in nature
b) Discuss items which AVRDC can deliver
c) A commitment from the NARS that they will conduct the research as planned (AVRDC does not conduct research on their behalf)
d) The NARS are willing to pool their resources in the region
e) The NARS in the region are willing to work together on issues common to the region
f) The NARS are eager to share their expertise
g) The NARS are ready to share responsibilities based on their ste NARS are ready to share responsibilities based on their strengths and weaknesses.

This paper is a brief account of the vegetable research network activities catalysed by AVRDC. Their impact and future plans are also described.


In 1988, an Asian Development Bank-funded consultation workshop brought together the four SE Asian (Indonesia, Malaysia, Philippines and Thailand) NARS and AVRDC for a discussion on the impact of collaborative research into vegetables. The four SE Asian NARS recognized their strengths and weaknesses, agreed to share resources and technical outputs in order to avoid duplication and benefit from a collaborative research partnership. Towards achieving such a partnership, the four countries prepared a Memorandum of Understanding, a framework for establishing the Collaborative Vegetable Research Program for Southeast Asia, or Asian Vegetable Research Network (AVNET). They asked AVRDC to be the executing agency and a partner in the network. AVRDC agreed.

Playing the role of catalyst, AVRDC encouraged the NARS to jointly develop a proposal for collaborative research with common priority objectives for the region for funding by ADB for three years beginning in 1989. Thus the NARS-initiated AVNET was born (fig. 1).

Following the success of AVNET, the South Asian NARS, through an ADB sponsored consultation, initiated in NARS, through an ADB sponsored consultation, initiated in 1990 the framework for the South Asia Vegetable Research Network (SAVERNET). The joint research proposal developed by the SAVERNET countries was funded by ADB in 1991.

In a similar fashion, Cambodia, Laos, and Vietnam developed a framework through a consultation sponsored by ADB and AVRDC and initiated the Cambodia, Laos, and Vietnam Network (CLVNET) in 1994. A research proposal developed jointly by the three countries and AVRDC has been approved for funding by ADB from 1996.

In addition, AVRDC has a Collaborative Network for Vegetable Research and Development in Southern Africa (CONVERDS) located at Arusha, Tanzania, and another Collaborative Network for Vegetable Research and Development for Central America (REDCAHOR) located at IICA, Costa Rica (fig. 2).

Specific Steps Involved in Establishing a Sub-regional Network

The above broad components can be modified to suit the needs in specific circumstances.

Structure of the Network

The structure of the NARS-initiated network is shown in fig. 3. Following the signing of a memorandum of understanding, each country nominates a senior administrator/vegetable specialist to be the steering committee member/national coordinator. Each country has a research team for each of the subnetwork activities. The steering committee is the policy-making and guiding body for the network. The network co-coordinator implements the project activities.

Accomplishments of Sub-regional Networks

1. Germplasm management and exchange

a) Collection and characterization of germplasm

AVRDC is the only international agricultural research centre conducting vegetable research and development. The principal crops of AVRDC belong to four major groups, namely, solanaceous (tomato, eggplant, and hot and sweet peppers), crucifers (common cabbage and Chinese cabbage), bulb alliums (onion, garlic, and shallot) and legumes (mungbean and vegetable soybean). In additionTRONG>legumes (mungbean and vegetable soybean). In addition, a number of regionally important crops, such as okra, amaranths, cucurbits, and leafy vegetables, also receive attention at AVRDC's regional centres in Asia and Africa. In October 1996, the total number of accessions in the AVRDC genebank stood at more than 43,500 (table 1).

Table 1. AVRDC germplasm collection, October 1996
Crop No. of accessions
Priority crops
Soybean (regional) 14,062
Tomato 6,921
Pepper 6,844
Mungbean (regional) 5,768
Eggplant 2,232
Brassica 1,510
Allium (onion, garlic, shallot) 752
Subtotal 38,089
Other crops
Yard-long bean and cowpea 1,614
Phaseolus WIDTH=129>1,614
Phaseolus bean (including lima bean) 548
Black gram 452
Luffa 286
Cucumis 275
Abelmoschus 230
Pea 211
Cucurbita 198
Lablab bean 175
Benincasa 133
Others 1,303
Subtotal 5,425
Total 43,514

AVRDC recognizes that an international effort directed at vegetables should try to cover many other vegetable crop species as well, taking into consideration the priorities of national programs, especially in developing countries. Towards that end, a project was developed with the following objectives: collect, characterize, and evaluate vegetable germplasm in Southeast Asia and possibly China and Indo vegetable germplasm in Southeast Asia and possibly China and Indo-China; establish a database with the data collected; multiply the seeds for distribution to national partners and for long-term storage; and offer training on germplasm management. The proposal was funded by the Japanese Government through the Japan International Cooperation Agency. Since 1989, the project has collected a total of 4,5 5 3 accessions consisting of 1 12 species from 52 genera belonging to 20 families in the Philippines, Indonesia, Malaysia, and Thailand. Six national program staff have been trained in germplasm management so far. As network members, the national partners actively participate in the collection missions and some of the seeds of collected germplasm are maintained in the national genebanks.

b) Germplasm exchange and evaluation of elite materials

The priority crops in different sub-regions differ considerably. For example, four AVNET countries had yard-long bean, cucumber, tomato, chili, shallot and garlic and they exchanged and evaluated 139 varieties of them among themselves. But six SAVERNET countries exchanged and evaluated 1 1 5 varieties of onion, tomato, chili, capsicum, eggplant, cauliflower, cabbage, musk melon, pumpkin, bitter gourd, cucumber and okra. The crops selected for CLVNET, CONVERDS, and REDCAHOR (CONVERDCA) are also different emphasizing the fact that there is diversity among sub-regional networks.

Within sixersity among sub-regional networks.

Within six years, one yard-long bean variety has been officially released to farmers in the Philippines. Although India is the leader in vegetable research among the SAVERNET countries, a chili variety from Sri Lanka has attracted the attention of farmers in India because of its colour, quality and yield. Similarly, a cabbage variety from Bangladesh, 'Probati', was found to flower and set seed under Delhi conditions. This trait is already being transferred to the Indian cabbage varieties so that seed can be produced in India instead of importing from abroad. Many Indian vegetable varieties did very well in other countries.

The hypothesis that a variety developed by a country within a region has an excellent chance of repeating the performance in another country within the region was found to be largely true. In some instances the cultural and personal preferences for shape, size, colour, and taste, rather than yield, determine the acceptability of a vegetable variety.

2. Integrated pest management of diamond back moth

The strategy in all the networks is to educate farmers to use integrated pest management (IPM) methods to save on cost of production, save the environment from pesticide pollution, and save people from the harmful effects of pesticide use.

The initial focus in AVNET was cabbage pest control with emphasis on diamondback moth (DBM) in the ontrol with emphasis on diamondback moth (DBM) in the highlands. The IPM strategy was to rear and release the parasitoids with a combination of Bacillus thuringiensis and judicious use of pesticides. Within three years, the network philosophy opened the eyes of the policy makers who made IPM a national policy in all four countries in Southeast Asia.

The economic benefits due to IPM in the pilot and demonstration farms were substantial. For example, the insecticide sprays were reduced by 51 to 86% and the yield of the crop increased by up to 50%. It has been estimated that if the technology is extended to the highland areas of the Cordillera alone in the Philippines and adopted by the farmers, a savings of up to US$10.5 million would be gained.

On the other hand, in SAVERNET the IPM components included parasites, trap crops (mustard was found to be effective), botanical pesticides (neem seed kernel extract spray was able to control several insects), and judicious use of insecticides. Following SAVERNET's example, AVNET-II included the SAVERNET components for evaluation.

Within three years in SAVERNET, the IPM package was piloted and demonstrated in Ooty, India, and a saving of US$60/ha was realized due to the withdrawal of pesticides in IPM plots. If the IPM technology is adopted nationwide it will amount to an annual savings of at least US$6 million in India alone. Not to mention the benefits to consumers and envirNot to mention the benefits to consumers and environmental safety. Farmers are becoming aware of the importance and benefits of using IPM. Gradually IPM is expected to dominate the pest control scenario.

Having successfully completed work on crucifers in the second phase, the SAVERNET countries have elected to focus their future research on tomato fruitworm and eggplant fruit and shoot borer management.

3. Tropical tomato and bacterial wilt

Tomato is one of the most popular vegetables in the Asia-Pacific region. In the tropics two major constraints limit tomato production: high temperature and bacterial wilt. AVRDC has developed heat-tolerant and bacterial wilt-resistant tomatoes. However, their performance in some of the Southeast and South Asian countries is not as expected. In those countries either the temperatures are much higher than what they temperatures in Taiwan or the host x parasite x environment interaction modifies the resistance to bacterial wilt and, as a result, the resistance is not expressed. To better understand and study the issue and to arrive at a resolution, a survey of bacterial wilt pathogens was undertaken in all the countries to identify the prevalent strains and biovars. An international bacterial wilt resistance screening nursery was established in all the network countries.

Based on the research results, an IPM package to manage bacterial wilt is being devel, an IPM package to manage bacterial wilt is being developed.

To enhance the fruit-set of tomatoes under high temperature, the use of heat tolerant varieties and application of hormone are recommended to farmers in the SAVERNET countries. In addition to the techniques identified for managing bacterial wilt by AVNET, in SAVERNET, Bangladesh has adopted grafting tomato on bacterial wilt-resistant wild tomato rootstocks.

Similarly, collaborative research has been fostered to unravel the issues related to tomato leaf curl and other viruses of tomato and pepper and also production technologies for tomato and pepper to overcome abiotic stresses.

Future Plans

1. Creation of subnetworks based on the needs of the sub-region and available resources

a) Mungbean subnetwork in South Asia

Of the total mungbean area of 3.1 million ha and production of 1.8 million t produced in South and Southeast Asia in 1986-87, almost 8 1 % of the area and 67% of the production were in South Asia. The growth in production during the last two decades was due to expansion in area rather than increase in the yield per unit area. The average yield of mungbean in the region has remained at around 300-400 kg/ha. The major obstacle to increased yield was the mungbean yellow mosaic virus (MYMV), a disease endemic to South Asia. So far efforts to develop resistant varieties by the NARS in South Asia orts to develop resistant varieties by the NARS in South Asia have met with limited success.

AVRDC has developed mungbeans with short growth duration and synchronized maturity which are well-suited to rice- or cereal-based cropping systems. In recent years, through shuttle breeding in collaboration with Pakistan, AVRDC has developed improved breeding lines with MYMV resistance and yield potential of 2.5 t/ha with about 65 to 70 days maturity.

Through the SAVERNET framework, a subnetwork on mungbean has been jointly developed by AVRDC and the NARS to evaluate improved mungbeans from the NARS and AVRDC, at strategic locations representing diverse agroecological zones using appropriate efficient production technology. Through the network, the improved mungbean can be tested not only in traditional mungbean areas but in nontraditional areas with better soil and moisture. The proposal has been approved by the Overseas Development Administration of the UK The project will be implemented from 1997.

b) Molecular approach in bacterial wilt studies in Southeast Asia

Estimates of loss due to bacterial wilt caused by Ralstonia solanacearum range from 15% to 95%, worth about US$25 to 158 million. In order to devise appropriate disease management techniques a joint subnetwork has been organized with AVNET, CLVNET, NARS, and Monash University in Australia. The subnetwork will study to understand the many races, biovbnetwork will study to understand the many races, biovars and strains in the pathogen and its relationship to disease and disease management.

c) Legume subnetwork under CLVNET

Legumes such as soybean and mungbean, are important protein sources for Cambodia, Laos, and Vietnam. Mungbean sprouts used widely in these countries are a key source of iron in the diet. The average yields of mungbean and soybean in these countries are around 500 kg and 900 kg/ha, respectively. The major constraints to mungbean and soybean production are susceptibility to diseases and insects, poor quality seeds, unadapted varieties, and lack of proper management technology.

Vegetable soybeans are emerging as an export crop in the region. They require freezing for value addition, hence, they provide excellent job opportunities for the rural poor, especially the women. Since vegetable soybeans are harvested when the pods are still green, and only pods with green seeds are used for consumption, nearly 75% of the biomass is recycled into the soil, thus enriching the soil organic matter.

Since Cambodia, Laos, and Vietnam lag behind in their total agricultural research and development, it is essential to bring them par with neighbouring countries in the region. Therefore, a joint project with the three NARS has been developed to train sufficient numbers of scientists in adaptive research, conduct adaptive research using AVRDC- anaptive research, conduct adaptive research using AVRDC- and the NARS-improved soybeans and mungbean; conduct on-farm trials, and demonstration trials; and develop cost-effective and environmentally friendly management technologies to produce high yield with acceptable quality.

2) Promoting Internetwork Interaction

Scientists from different networks will be encouraged to participate into workshops organized by others to facilitate exchange of technology among subnetworks.

Using AVRDC's Tropical Vegetable Information Service, information will be exchanged among the networks. The TVIS Newsletter will be used as the vehicle.

All countries have agreed to freely exchange germplasm and improved technology for mutual benefit.

Wherever possible, experts from one network will be used as resource persons for other networks.

AVRDC proposes to catalyse the organization of workshops on topics of common interest for cross-network interaction. For example, urbanization and periurban vegetable production are common issues for all networks.


AVRDC has served as a catalyst in the establishment of several subregional vegetable networks around the globe. Such collaborative networks serve as the major vehicle with which AVRDC interacts more effectively with the NARS.

Once AVRDC has gained sufficient experience and the NARh the NARS.

Once AVRDC has gained sufficient experience and the NARS continue to make progress, the effectiveness of the collaborative network approach can be evaluated based on whether it can improve the efficiency of the NARS to better utilize their limited resources available for vegetable research.

AVRDC considers the networks as institutions rather than projects and therefore they are independent of external funding. External funding was instrumental in the initial stages for the partners to come together to experiment on the usefulness of such an arrangement. The sustainability of the network depends largely on the commitment and willingness of the partners to exchange and share available resources once they are convinced that the network arrangement is mutually and collectively beneficial. External funding is important to improve the effectiveness of the networks. Periodic get-together of the partners are essential to maintain the collaboration and sustain the interaction.

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