The promising future of Sesbania rostrata Reducing the need for commercial fertilizer

A seminar in Dakar, Senegal, in January 1988 broke new ground by bringing together two types of researchers who do not often meet: those doing fundamental scientific research and those working on the practical application of such results. The occasion was an international seminar on Sesbania rostrata which was organised by the CTA in collaboration with ORSTOM (the French development research agency) ISRA (Senegal's national agricultural research institute), and the genetics laboratory of the University of Ghent in Belgium.

The participants from more than 30 countries, discussed the results of their work and identified the problems posed by the integration of S. rostrata (and other plants with nitrogen-fixing nodules on . their stems) in the cultivation practices of African and Asian farmers. S. rostrata is an adventitious nitrogenfixing plant that is frequently found in the Senegal River valley as well as throughout the Sahel.

Although well known for many years, this plant was not studied in any depth until 1979 when ORSTOM researcher, Dr B. Dreyfus, discovered nitrogen-fixing nodules on its stems. This discovery hailed the beginning of basic research which rapidly developed throughout the world in 20 or so laboratories which analysed the physiology and genetics of the micro-organism responsible for the stem nodules. It is a new type that combines the properties of free nitrogen-fixing bacteria (like Klebsiella) and symbiotic bacteria (like Rhizobium). In fact, it was during this very seminar that this new bacterium was officially baptized as Azorhizobium caulinodans. At the same time as this basic research was started, agronomic researchers from 20 or so African and Asian countries began to examine the possibility of exploiting this new system capable of fixing high levels of nitrogen whether for irrigated crops (particularly with rice) or for rain-fed crops (notably with row crops).

The seminar gave a platform for the results of the latest research on the symbiosis of S. rostrata and A. caulinodans which appears more and more often as a priority subject for experimental trials. Such discoveries dealt first of all with the genetics of Azorhizabium. The substances that initiate and regulate nodulation have now been identified as well as the new genes that fix the nitrogen. The study of the interaction of Sesbania-Azorhizabium at the cellular level has, for the first time, enabled the in vitro development of nodules based on the infection of S. rostrata protoplasm by Azorhizabium. Such nodules will no doubt enable future research in this area to advance current knowledge of the cellular interaction between these two organisms.

The recent result of a plant/host mutant that does not have nodule sites opens the way to the identification of genes coded for this remarkable characteristic of nitrogenfixing stem nodules. The seminar also provided the opportunity for an update on the most recent molecular biology techniques capable of producing transgenic plants which have resistance to viruses, insects or herbicides.

Researchers at the seminar also confirmed preliminary observations which suggested that S. rostrata has considerable nitrogen-fixing potential. This exceptional symbiosis between S. rostrata and Azorhizabium explains the success of the use of S. rostrata as a green manure which, in almost all cases, enables the yield of irrigated rice to be doubled.

As for row crops, the contribution of S. rostrata to nitrogen supplies of associated plants is less signficant but still substantial. New uses of S. rostrata were also presented, including its ability to provide forage, fuelwood and pulp. In Senegal, it has even been shown that its leaves can be used for human consumption. The comprehensive study of the integration of S. rostrata in agriculture has already identified certain limits to its use, notably its sensitivity to a short photoperiodicity and to certain nematodes in areas that were flooded.

At the end of the seminar, numerous recommendations were made primarily to co-ordinate both field and laboratory research. They will be included in the proceedings which will be jointly published by CTA and ORSTOM.

New crops for food and industry

If it is agreed that the world has the potential resources to support its future population, it must also be acknowledged that - if governments should concentrate on the more equitable distribution of those resources - scientists and agriculturalists must direct their efforts towards new means of utilizing them.

This will entail producing new forms of old crops by breeding and selection, domesticating and managing wild species, and using biotechnology to create new plants.

It was to discuss future needs and developments in this field, and to put members of different disciplines in touch, that 130 participants from 33 developed and developing countries from all five continents gathered at the University of Southampton, U K from September 22-25 1987. The occasion was a Symposium on New Crops for Food and Industry, sponsored among others by CTA.

This symposium was a response to the global interest in increasing and sustaining agricultural productivity without contributing more to the surplus of the well-established staple crops of North America and Europe. But perhaps the most positive result of the gathering was the establishment at Southampton of a centre to develop and exploit under-utilized crops for food, energy and industrial raw materials in the tropics, sub-tropics, arid and semiarid and temperate regions.

CTA supported the attendance of two experts from ACP countries and delegates heard 41 papers on topics ranging from less-known oil-bearing plants to Indonesian seaweeds; development for industry, from biomass production in the desert using algae to the potential of herbal drugs; and to argue vigorously on behalf of their own individual crop specialities.

Despite such individual enthusiasm it was established that the needs of developing countries must come first, and to meet these, various criteria for crop priority emerged from both papers and discussions. They included the market potential and utility of the crops, the socioeconomic and the agricultural-environmental benefits, the degree to which systems can be developed to sustain production, the degree to which a new crop will help stabilize a shifting cultivation system or enable a fragile drought-prone environment to be stably productive; whether it is both independent of major agrochemical inputs and pest and disease-resistant, and the management of the genotype and environment interaction during development.

Other important priorities followed: that funding should not be wasted on new crops whose viability was open to serious doubt and that the conservation of genetic resources was vital. There was universal acknowledgement of women's role in agriculture, and of the social and agricultural importance of smallholdings in tropical countries.

It was further agreed that international agencies such as FAO, IBPGR, CGIAR, etc, should allocate funding to new crops, that these bodies should commit funds on a long-term basis rather than on shorter "seed" programmes.

The most concrete result of the symposium arose from a forum on the final day, chaired by Professor P Day from the Center for Agricultural Molecular Biology, Cook College, Rutgers University, New Brunswick. The symposium adopted the University of Southampton's proposal for a Centre for Under-Utilized Crops (International Co-ordinating Centre).

This establishment, which came into being on January 1 1988, will assist in and co-ordinate research and development in the field and laboratory, offer training courses on topics related to new crop development, start a newsletter and set up a database that will interact with others at Kew near London and elsewhere

Women in development

CTA is to fund a bibliographic project on the role of women in agriculture in southern Africa. The need for such a project was identified during a CTA-sponsored workshop on Agricultural Information Sources in Lilongwe, Malawi between June 15 and 261987 where 25 participants were trained in the use and production of bibliographic tools. This project, like the workshop, is expected to bring benefits in both the short and long term.

Women have always played a vital part in Third World agriculture, and in Africa they produce 90% of all domestically consumed food. But the raised feminist consciousness and educational standards of the 1980s, and the expectations arising from these, have only recently brought an awareness of the need to collate the increasing amount of written material on this subject.

The bibliography will list all published material on women in development in the four southern African nations of Botswana, Lesotho, Malawi and Zambia (chosen because they share a common experience of women's work). It will also attempt to collate information which originates from the Commonwealth, the Third World, ACP countries, and non-aligned countries, analysing by subject and identifying areas not covered.

The researchers, three women and one man from the four countries involved, aim to recognize and evaluate the quality, quantity, nature and subject scope of material available in their own countries. By providing potential users with a guide to existing data they hope to reduce unnecessary duplication of research and development schemes. They also seek to assist local libraries and documentation centres in amassing the identified literature, and to establish active cooperation from its producers.

Thus they intend to bring into being the basis of an ongoing bibliographic source on women in development and on other related topics which may eventually be expanded to cover Africa as a whole

The researchers hope, by extension, that through the increased awareness engendered by such a bibliography, women can be encouraged to participate actively in national, regional, and even continental economic life and, as one contributor put it, "to spearhead the integration of women in development in southern Africa

New control for Panama disease

Scientists in India believe that a new control technique may prove cost-effective in controlling Panama disease the widespread fusarial wilt that inflicts serious damage on bananas.

The new technique involves injecting a solution of 2% carbendazim directly into the corm, and the researchers from Tamil Nadu Agricultural University have compared this treatment to soil drenching with Methoxy ethyl mercuric chloride - the common treatment at present and to using a combination of the two methods. Results show that the new technique is extremely effective, indicating the curative action and stimulation of plant growth by carbendazim. The best control of all was given by the combined treatment, though the optimum cost-benefit came from the corm injection on its own. Similar effects from the application of carbendazim have been reported in other crops.

For more details, contact:
Department of Plant Pathology Tamil Nadu Agricultural University Coimbatore 641 003 INDIA

Fellowships for African researchers

The Project on African Agriculture: Crisis and Transformation is offering fellowships to African researchers or to research teams working alongside them for innovative projects that combine both training and research activities.

Interdisciplinary approaches that analyse the agricultural crisis in Africa are particularly favoured. These fellowships are designed for recent graduates working in research institutes or universities as well as government agencies.

For more details, contact:
Fellowship Program Project on African Agriculture Social Science Research Council 605 Third Avenue New York, N Y 10158 USA

PESTNET Now for Rwanda - The African Regional Pest

Management R&D Network, better known as PESTNET, has recently finalized the programme and budget for its proposed activities in Rwanda. From the start Rwanda was identified as one of four countries where PESTNET hopes to place emphasis on the generation of desired pest management production technology and to test methodologies, technologies and information for validity.

In particular the programme and budget now approved will cover proposed collaborative research on the assessment of the stemborer problem in Rwanda on sorghum and maize - the two important staple food crops in the country's economy.

For more details, contact:
PESTNET Coordinator International Centre of Insect Physiology and Ecology P O Box 30772 Nairobi KENYA

Microcatchments increase yields

Farmers in Somalia's northwest region have recently completed trials which show that a new water retention system increases their yields for less work.

Farmers had been using standard bunds to conserve soil and use available rainfall more efficiently. Last year, a field engineer, Kenneth Proud, tried another method. He got farmers to plant only a small area above existing bunds. Then the remainder of the land was smoothed and used as a microcatchment which supplied water to the cultivated area. The ratio of cultivated land to catchment area is crucial. Soil type, degree of slope, and rainfall must also be taken into consideration.

With sorghum requiring between 450 and 650 mm of rainfall to produce a good yield, the catchment area had to be three times the size of the planted field. Each field has above it a catchment area that feeds water solely to that field.

In the trials the smaller, but better-watered fields yielded the equivalent of 1,869 kg per hectare. Yields on 100 traditional farms were about 230 kg per hectare. Not only were yields better but inputs were greatly reduced. Farmers have now asked the World Bank for help in extending the system.

Source:
New Scientist February 4 1988 New Science Publications Commonwealth House 1-19 New Oxford Street London WC1A ING U K

Bollworm control with pheromones

Work at the Central Cotton Research Institute in Pakistan has shown that using sex pheromones to disrupt cotton bollworm mating may offer a non-toxic alternative to chemical control.

Three bollworm species, Pectinophora gossypiella, Earias vittella and E insulana, cause serious losses in cotton crops, and chemical control has proved problematic, particularly because of the adverse effects on beneficial insects and the difficulty in timing applications accurately. Sex pheromones - the chemicals released by insects in minute amounts to attract a mate offer easier control of the pest and the preservation of beneficial insects as well as avoiding the possibility of pesticide resistance building up.

The major pheromones of each of the three species are formulated together and applied by hand at the pin square stage by means of rope or twist ties. The level of disruption achieved can be measured by reductions in pheromone trap catches. In the experiments so far, the new control technique has proved so effective that researchers also report an almost complete lack of moth flying activity following one simple application. Results suggest that more than 99% disruption can be achieved for P. gossypiella and E. vittella, with 89.5% for E. insulana. This is taken as evidence that a significant lowering of reproductive rates should be attainable in the not too distant future.

For more details, contact:
Central Cotton Research Institute Old Shujabad Road Multan PAKISTAN

Traditional livestock treatment

A databank on traditional ways of treating livestock illnesses in tropical regions is currently being established.

The group of veterinarians involved in this project hopes to collect specific information such as: animals treated and their age, their illnesses, the techniques and substances used to cure them, the effects as well as the region or country involved.

For more details, contact
Heifer Project Exchange Dean Roedke RDLO P O Box 57 Mbeya TANZANIA

Communication consultants

A multi-media group of experienced consultants has been formed by the Danish Broadcasting Corporation. Called DaniCom/Danish Development Communication Consultants, the group is a not-forprofit consulting service specializing in communication and media in Third World countries.

Media and communication often come into project formulation at too late a stage, with the result that promotion of the project idea and local support never get a chance to develop fully. DaniCom sees communication as a system for promoting local initiative through information, feedback and dialogue, and offers expertise in radio, audio cassettes, TV, video, cine film, still photography and printing.

For more details, contact:
DaniComm Danish Broadcasting Corporation Radiohuset DK-1999 Fredericksberg C DENMARK

Living beehive legs

Living beehive supports are being used by traditional beekeepers in Uganda in order to support both traditional and topbar type hives.

In the tropics hive supports can be easily damaged by termites or rot. If hives are kept in trees they are usually not easily accessible for frequent inspection. So Ugandan beekeepers have developed live supports. They cut two large stakes, with a suitable "Y" shape, from either the bark cloth tree, Ficus natalensi, or a species of coral tree, Erythrina abyssinica. The stakes are placed in the ground at a distance apart to suit the hives. Hives can be placed firmly in the Y or they can be suspended by wires strung from the posts.

In time the posts will sprout and the branches and leaves will shade the hives from the sun. It is also possible to use the leaves as a fodder for livestock, or as a mulch.

The living hive supports are a good example of agroforestry and apiculture coming together.

Source:
November 1987 newsletter International Bee Research Association 18 North Road Cardiff CF1 3DY U K

Documenting mycotoxins

A reference library is currently being established by UNEP in Nairobi to help African countries control mycotoxins and to take preventative measures for the future. It will bring together all the literature that has been published on this subject. The authors of articles, brochures or publications on mycotoxins are invited to ensure that their work is included in this collection.

For more details, contact:
Mycotoxins Reference Library UNEP P O Box 30552 Nairobi KENYA

Funds available for research

The Directorate General for Science, Research and Development of the Commission of the European Communities (CEC) has announced a second research and development programme "Science and Technology for Development".

This consists of two sub-programmes for which research proposals are requested. Of particular interest to SPORE readers will be the sub-programme "Tropical and Subtropical Agriculture" whose expenditure commitments are estimated at approximately 55 million ECU. This programme comprises four broad sectors covering the improvement of agricultural products, conservation and better use of the environment, agricultural engineering and post harvest technology, and production systems. Detailed aspects of each of these sectors and the particular objectives of the Commission in funding suitable research projects are set out in the application documents which can be obtained from the address below.

Proposals will be selected on the basis of a number of factors one of which is the possibility of collaboration between research bodies in the members states and in developing countries.

The call for proposals is open for two years from mid-December 1987 and the Commission wishes to receive proposals for participation in this sub-programme according to the following schedule of dealines:
Phase 1 February 291988 Phase 2 June 30 1988
Phase 3 December 31 1988 Phase 4 June 30 1989
Phase 5 December 31 1989

The phasing of the call for proposals and the selection of projects for funding are necessary for technical and financial reasons, and the date of reception will have no adverse effect on selected proposals.

For more details, contact:
Mr C Uzereau Tropical and Subtropical Agriculture DG Xll, CEC rue de la Loi 200 B-1049 Brussels

Sweet potato for food and industry

Sweet potato cultivation provides both employment and food for Nigeria and many other countries where the crop is grown. It is the sixth most important food crop in the world and has several advantages over other staples. It has, for instance, a tremendous capacity for producino drv matter per unit area of land in a short time and it requires fewer production inputs than yam, cassava or other staple crops. It is also less vulnerable to drought and heavy storms.

S C O Narinyi of Nigeria's National Root Crops Research Institute highlights sweetness, strong taste and aroma, and the colour of the cooked product, as the most important areas requiring attention if the acceptability of sweet potatoes is to be enhanced. Deep orange and violet (or purple) flesh colours are disliked and white or yellow fleshed cultivars are generally preferred. Also, while other staple crops such as rice, cassava, potato, yam and cocoyam have little taste and need flavouring to increase palatability, many consumers object to the taste and smell of sweet potato. Nevertheless, others consume sweet potato because of its sweetness and flavour so there is opportunity for selection to modify these characteristics to suit a greater proportion of the population.

Industrial processing is another option for modifying appearance and taste: tubers are now peeled, sliced, dried and milled into flour, which can be used in various food preparations. With maize and soya bean flours, good infant foods have been produced and sweet potato flour blends well with wheat flour for making bread, biscuits and cakes.

High yielding cultivars from the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria are in demand From farmers and further cultivars are on trial. With yields of 25-40 t per hectare, a growing period of three to four months, wide ecological adaptation, easy preparation and low input requirements, the sweet potato obviously has considerably unexploited potential as a major crop.

For more details, contact:
S C O Narinyi National Root Crops Research I nstitute Umudike PMB 7006 Umuahia NIGERIA

Electrostatic spraying

An air-assisted electrostatic sprayer has been used successfully in glasshouse trials to apply less than 1 litre/ha of pesticides to control whitefly in tomatoes. The technique has been tested at the AFRC Institute of Horticultural Research, Littlehampton, U K. High volumes (1,000 litres/ha) of insecticide sprays are wasteful because the majority of the chemical is deposited on upper leaf surfaces, or 'runs off' to the ground, whilst the pests feed on the undersides of the leaves.

The air-assisted electrostatic sprayer produces tiny charged droplets of chemical and achieves good penetration of the crop canopy. The electric charge attracts the droplets equally to both sides of the leaves. As a result, much more of the chemical reaches the parts of the crop where it could be effective against the pest.

Glasshouse trials have also shown that insecticides may be applied selectively to the apical foliage of tomatoes to control adults, eggs and young larvae of whitefly. This minimizes contamination of fruit and reduces harmful effects on the whitefly parasite Encarsia.

For more details, contact:
Peter Grimbly AFRC Institute of Horticultural Research Littlehampton Sussex U K

New bulletin on bananas

"Musarama" is the title of a new bulletin published by the International Network for the Improvement of Banana and Plantain (INIBAP) with the support of CTA and the International Development Research Centre (IDRC). This quarterly, whose first issue has just appeared, is designed to inform and put in contact all those who work on bananas and plantains.

Contributions are actively encouraged.

For more details, contact:
Musarama INIBAP B P 5035 34032 Montpellier Cedex FRANCE

Horticultural databank

Fieldworkers, researchers and documentation centres can now make requests to the databank of the Horticultural Crops Group of the FAO for information on high yielding varieties of fruits, vegetables, root crops or tubers. Such information can be provided according to geographical zones, the species or the crop

For more details, contact:
Horticultural Crops Group FAO Via delle Terme di Caracalla 00100 Rome ITALY