FOREWORD

With the failure of earlier emphasis on cereals to bridge the food production gap, serious attention is currently being given to the development and promotion of some traditional starchy staples in many countries. Tropical root and tuber crops such as cassava, yam, cocoyam, sweet potato, and Irish potato have been recognized as the greatest sources of dietary food energy for majority of developing countries. Apart from the importance of these crops in food security and food self-sufficiency, they contribute significantly to national economies and rural income', and provide employment for most rural women in sub-Saharan Africa.

The Government of Ghana hosted the ninth symposium of the International Society for Tropical Root Crops (ISTRC) under the theme “Tropical root and tuber crops in a developing economy” in Accra in October 1991. The Director-General and staff of the International Institute of Tropical Agriculture (IITA), based in Ibadan, Nigeria, gave immense support to the organization of the symposium and the publication of this proceedings.

The Accra ISTRC symposium was well attended by scientists, policymakers, and representatives of producer and user groups of tropical root crops worldwide. The symposium acknowledged the value of tropical root and tuber crops in human nutrition and their importance in food security, food self-sufficiency, and national economies. It was clearly evident that tropical root and tuber crops are vital to bridging the food production gap in most developing countries. Furthermore, it was indicated that the current levels of production of these crops could be increased through the adoption of improved varieties and sustainable husbandry practices. Finally, issues related to postharvest management such as marketing and processing were identified as major constraints which hamper the development of tropical root and tuber crops in developing countries.

On behalf of the Government and People of the Republic of Ghana, I would like to express my warm appreciation to the Governing Council of the ISTRC for this unique opportunity offered to Ghana to host the ninth symposium, which created the awareness of the relevance of tropical root and tuber crops to the socioeconomic development of most developing countries. It is envisioned that the ideas which were shared by participants will contribute to the improvement of technologies for the production and consumption of these crops.

Ibrahim I. Adam, Minister of Food and Agriculture.
Accra, Ghana
June 1994


WELCOME ADDRESS

Honourable PNDC member, colleague PNDC Secretaries of State, your Excellencies, the President and members of the Executive Council of the International Society for Tropical Root Crops (ISTRC), invited guests, participants, ladies, and gentlemen.

On behalf of the Government and the people of the Republic of Ghana, and on my own behalf, I would like to welcome you to our beautiful country, Ghana, for the 9th symposium of the ISTRC. I acknowledge, with appreciation, the numerous foreign participants in our midst and hope that you will enjoy your stay during and after the symposium.

I wish to take this opportunity to welcome Professor K. Caesar and members of the Executive Council of ISTRC for endorsing the hosting of the 9th symposium of ISTRC by the Government of Ghana. The PNDC Government of Ghana is grateful for this privilege and honor to organize this symposium which is the first to be organized by the ISTRC in conjunction with an African government. The 3rd symposium held in Africa in 1973 was organized on behalf of the Society by the International Institute for Tropical Agriculture (IITA) in Nigeria.

ISTRC is the only institution that has, since its inception in 1967, succeeded in assembling scientists of various disciplines from all over the world to upgrade the knowledge and achievements on the production, storage, and processing of root and tuber crops.

Tropical root and tuber crops, including cassava, yam, sweet potato, Irish potato and cocoyam, contribute relatively more to the diets of both humans and livestock in many developing countries that are being represented at this symposium. These crops contribute substantially to the economies of most of these countries, provide more than 60% of the daily caloric intake of majority of the people, and ensure access of the populace at all times to enough and affordable food for sustained and healthy life.

Despite the significant importance of roots and tubers as insurance crops for the alleviation of food deficits which ensure food security and self-sufficiency, these crops have not received a fair and adequate share of attention by governments and researchers attention. They have been relegated as rural staples by cereals and other crops due to inadequate technologies and budgetary allocations in our respective countries. These have culminated in the slow development of technology for the production, storage, and processing of root and tuber crops.

Your participation in this symposium is a manifestation of your concern for resolving some of the key issues and constraints associated with tropical root and tuber crops on which most of our countries rely heavily for economic emancipation.

The large number of foreign participants to this important scientific meeting on root and tuber crops has been made possible by the generous financial assistance offered by various international research institutions and programs, donor, and aid agencies which include IITA, the International Foundation for Science (IFS), the International Development Research Center (IDRC), the German Foundation for International Development (DSE), CTA, the Rockefeller Foundation, and other organizations. I would like to express my deepest gratitude for the excellent moral support of these organizations for sponsoring participants from around the world to Ghana for this symposium.

I trust that the exchange of ideas and experiences among participants from different countries would unveil new areas of research that would stimulate the production, storage, and processing of root the tuber crops as basic food staples and crops for household food security in the developing world.

I would like to thank the European Economic Community (EEC) for providing support that has encouraged many local scientists, lecturers, and staff of my ministry to attend this symposium. I would also like to offer my Government's gratitude to IITA for its sustained interest and support towards organization of this symposium. IITA has also offered to publish the proceedings of this symposium and an editorial team made up of IITA and Ghanaians scientists has already been formed for this assignment. This exemplifies a successful collaboration between an international research institution and a national agricultural research system which will eventually enhance the skills of the Ghanaians in the editing of scientific publications.

The Symposium Planning Committee has carefully selected chairpersons and rapporteurs from various disciplines of root and tuber crops for the various sessions. I am optimistic that you would ensure orderly and timely presentations and keep track of key areas of the various contributions for the Editorial Committee.

Finally, I would like to thank the Local Planning Committee and the IITA liaison assistant for the several months they have worked towards this symposium.

I wish you very fruitful deliberations and a very happy stay in Ghana. I hope that our foreign participants will find time while you are here to enjoy the warm hospitality of our land and people. On Wednesday, there will be a field trip to Kumasi and participants will be introduced to our National Root and Tuber Crops Improvement Program, there will be a variety of local dishes prepared from roots and tubers and you will be treated to aspects of typical Ghanaian culture.

On behalf of the PNDC Government of Ghana, may I take this opportunity, once again, to express our thanks to ISTRC and the various sponsors for making this 9th symposium of ISTRC possible and I wish you a successful scientific meeting.

Thank you.


PRESIDENTTIAL ADDRESS

Honorable Minister, your excellencies, distinguished guests, dear participants, ladies, and gentlemen.

It is a great pleasure to see you all again at another symposium of the International Society of Tropical Root Crops (ISTRC).

It is also a great pleasure to be here in Africa again where we hope to bridge the language barrier between the English- and French-speaking regions.

About 200 participants and 120 presenters have been registered, and for the very first time in the history of our symposium we shall be having a poster session.

But neither the best and most attractive country nor the best and most attractive program would lead to a successful symposium if money is not available.

ISTRC is a non-profit making organization which has the subject of tropical root crops as its focal point. It depends entirely on sponsorship for its symposia which depends entirely on the efforts of the Vice-President responsible for fund-raising. Our thanks therefore, goes to Dr. Cooke and his staff who have been very active and successful in soliciting funds for travel grants. The agencies and institutions that provided us with so much help will be mentioned in the proceedings of this symposium.

This symposium mainly serves as a forum for sharing and exchanging scientific findings, and the reputation of the society depends on the quality of scientific presentations at its symposia. As an incentive, we have again three awards to present.

These are:

• The Research Achievement Award which was dedicated by the former president Dr. Donald Plucknett with US$250.
• The Best Paper Award of this symposium, also dedicated by Dr. Plucknett with US$100.
• The Pat Coursey Research Award for research work on yams, dedicated by our society with US $250.

The first award has Dr. Plucknett, himself, as the sole judge. The second will be judged by a committee to be constituted within the symposium and the third will be judged by a committee formed by the council.

For the sustenance of the society and its future programs there will be a general meeting in accordance with our constitution to discuss the welfare of the society and its scientific work. I would therefore urge all members to attend and to participate actively.

Last but not the least, I would like to thank the organizers for their efforts in making this symposium a success. Particularly I have to mention the Ministry of Agriculture of Ghana and its staff, and our colleagues from the International Institute of Tropical Agriculture (IITA), Ibadan. I wish you all a fruitful deliberation, a successful symposium and a happy stay in Ghana.


OPENING ADDRESS

PNDC Secretaries of State, your Excellencies, the President and members of the Executive Council of the International Society for Tropical Root Crops (ISTRC), distinguished scientists, invited guests, participants, ladies, and gentlemen.

It is my greatest pleasure and privilege to be invited to deliver the opening address of the 9th symposium of ISTRC. On behalf of the Government and people of Ghana, I welcome you all, particularly our foreign participants, to this very important scientific meeting. I wish to extend my special welcome and thanks to Professor Knud Caesar and other members of the Executive Council of the ISTRC for selecting Ghana to host the symposium.

Ghana is indeed grateful for this privilege and honor to organize this symposium which I am informed is the first to be organized by the ISTRC in conjunction with an African government.

The gathering of so many leading scientists from both international and national agricultural research institutions from around the globe in Ghana for this five-day symposium to exchange latest experiences and ideas on tropical root and tuber crops will no doubt stimulate not only our researchers, but also our policymakers as well as our extension officers and farmers to redouble their efforts in the development and promotion of these crops which are the traditional staples in Ghana but whose development, production, and utilization have been marginalized over the years.

The theme of the symposium-Tropical root and tuber crops in a developing economy-is therefore most appropriate. The potential contribution of the major tropical root and tuber crops: cassava, yam, sweet potato, and cocoyam to the economies of most tropical and sub-tropical developing countries cannot be over emphasized. In Ghana, for example, cassava, yam, plantain, and cocoyam alone contribute as much as 59% of Ghana's Agriculture Gross Domestic Product (AGDP) (excluding forestry) evaluated at 1987 constant prices. Cassava's contribution of 19% of AGDP is said to be higher than that of cocoa; whilst yam, and to a lesser extent cocoyam, individually contribute almost as much as cocoa AGDP.

In most of our countries, these crops are closely associated with food security and complement the objectives of protecting the populace against malnutrition. They also ensure revenue-generating activities for most rural dwellers and provide the bulk of the daily caloric intake of majority of our people. In fact root and tuber crops have been described by some as “insurance crops” which survive very arduous tropical conditions.

The potential for the use of root and tuber crops as a source of cheap feed for the development of the livestock industry has, to a large extent, not been explored to the extent that the livestock industry continues to rely heavily on imported feed and feed ingredients to the detriment of our balance of payment situation, thus aggravating our debt crisis.

Yet root and tuber crops receive a very insignificant proportion of the research funds available for agricultural research in Ghana. I am sure the same may be true of other countries in Africa.

However, distinguished participants, ladies, and gentlemen, the Ministry of Agriculture, having recognized the enormous contribution which roots and tubers could make to the attainment of the objective of the Economic Recovery Programme (ERP), has decided to actively promote the efficient production, processing, and utilization of these crops to their full potentials. The hosting of three seminars and symposia since June this year is a clear manifestation of our commitment in this regard.

It is gratifying to note that ISTRC has, since its inception in 1967, been leading the crusade through research by its members to upgrade knowledge in the promotion of root and tuber crops in the developing world.

I trust that the exchanges of ideas and experiences among participants which I am told include, policymakers, extentionists, farmers, and other agriculturists from as many as 60 countries would highlight the numerous constraints that hamper the production, and utilization of these crops. I also trust that appropriate solutions would be advanced to address these constraints.

Distinguished participants, permit me at this juncture to mention some major constraints or problem areas which I think you should examine among others:

1. The production of some tropical root crops has been stagnant for several years in many countries due to lack of improved varieties to replace local types. It is therefore necessary to closely collaborate and coordinate research efforts among international and national agricultural research institutions to tackle this problem in the shortest possible time.
2. A related constraint to the shortage of planting material is that of diseases and pests. The mosaic virus continues to reduce yields while the green spider mite and mealy bug have established themselves as formidable foes of cassava farmers. Other root and tuber crops may be luckier, but as scientists, you should anticipate greater incidences of pests and diseases as production becomes intensive, as is now being experienced in land-deficient countries. I know about the achievements already notched in the control of some of these pests and diseases but the cost of doing so is beyond the means of many developing countries, hence international efforts are still required to contain the situation.
3. In Ghana, there has been no significant change in the method of planting and harvesting of cassava since the crop was introduced into the country over a century ago. The sticks are cut the same length, planted, and harvested the same way. During harvest, half the crop is usually left in the ground especially during the dry season. There is, therefore, the urgent need to develop appropriate planting and harvesting technology which our small-scale farmers can afford while also improving their productivity and efficiency.
4. The problem of storage is perhaps even more serious than that of planting and harvesting. Postharvest losses in most of our countries is reported to be very high. In Ghana, it is 15–25% in normal years. This is mainly due to lack of appropriate means of storage of our farm produce particularly root and tuber crops. From time immemorial, cassava was stored by our people by burying it in the ground behind kitchens. Today most of our women still store their cassava in the same old way. Certainly we have among you scientists who could propose more appropriate and cost-effective storage technologies to avert high postharvest losses and thereby improve the socioeconomic status of our farmers.
5. Another problem area is that of processing. Most of our countries, including Ghana, are faced with the problem of increasing import bills arising from cereal imports especially wheat, and due to the rapid expansion of the demand for “convenience foods” as our countries become more urbanized. Improved methods of processing will not only reduce postharvest losses but will also enable us provide local substitutes for these imported “convenience foods” as well as generate employment opportunities, and raise household incomes while making the products acceptable and competitive in both domestic and foreign markets.

Distinguished participants, during the last symposium in Bangkok, Thailand, Professor Knud Caesar, in his presidential address, stressed the need for a closer cooperation between the ISTRC and International Society for Horticultural Science (ISHS). I am informed that this has resulted in the efficient administration of the affairs of the ISTRC during the last three years. I wish, in the same spirit, to request that the parent body of ISTRC duly recognizes the ISTRC-Africa Branch as part of the world body which is also concerned with elimination of the constraints to the production, storage, and utilization of tropical root and tuber crops and give the necessary support to execute its mandate.

I am hopeful that the research results to be presented in this symposium would help to promote the production of more root and tuber crops which are essential for our local diets as well as for our economic development.

Before I conclude, I wish to remind our foreign friends of the proverbial Ghanaian friendliness and hospitality. Please do not spend all your five days in Ghana within the walls of this hall. Try and organize your schedule so as to have a few hours for play. For it is said that “all work and no play makes Jack a dull boy”.

Finally, I wish to express my appreciation and gratitude to institutions, donors, and aid agencies, especially the European Economic Community (EEC), which provided much financial resources to participants.

On behalf of the Provisional National Defence Council (PNDC) Government, may I take this opportunity once again to express my gratitude and appreciation to ISTRC for organizing this symposium in Ghana. I hope, rather I am indeed confident that you will have a successful deliberation.

Your excellencies, distinguished scientists, ladies and gentlemen, on this note I now have the pleasure and honour to declare this 9th symposium of the International Society for Tropical Root Crops formally open.

Thank you.


CLOSING ADDRESS

Honourable Deputy Secretary, dear colleagues.

We have come to the end of yet another very interesting symposium. A good blend of invited and special papers delivered at the plenary sessions gave us an overview of root and tuber crop research in the tropics. Although the number of participants from Asia and Latin America were not as high as expected, the level of participation was generally impressive. This shows that the number of researchers in root crops have increased and is still increasing, reflecting the importance of these crops to farmers as producers and consumers. This also means that the interest to deliver papers at such conferences will be increasing to an extent that it will be difficult to accommodate. It would be helpful if we could pay more attention to poster presentations which should be considered equally valuable in the future; alongside the Best Paper Award, a Best poster award should also be considered.

Looking back to what we have heard and seen, cassava still dominates our presentations. However, yam also plays a major role as a staple in the diet of West Africans. The Irish potato was well covered, while sweet potato and aroids had fewer presentations, not to speak of other root and tuber crops which have even more local importance.

In the fields of specialization, I have the impression that crop physiology (in the strict sense) has not been given adequate attention as compared to agronomy. But I feel that increased crop production very much depends on the understanding of plant behaviour, and reactions than from merely influencing cropping methods. In addition, we also need more emphasis on a systems approach as was presented in some of the invited papers. The same applies to quality of plant products, and there is still too much routine work in research and very little in terms of originality of ideas. This certainly will affect the editing of the proceedings. The reputation of ISTRC depends on the quality of scientific presentations. The Council together with the editors have decided to be strict in the selection of papers. The editors are therefore not to be blamed as they have the full support of the Council. We need to maintain standards as a means of attracting sponsors for our conferences.

There is still room for improvement with the oral presentations. Even though there were some problems with the slide projectors and rather small screens, some of the papers were just not properly prepared. A speaker should be able to realise when he blocks the view of his audience with his posture or talks to the wall instead of the audience. Such instances are avoidable and could have been corrected by the chairperson who should not only control the time but should also help in the presentation.

All these criticisms are directed towards ourselves and aimed at helping us to improve the scientific standards of our society. This does not in any way demean the value and importance of this symposium, particularly the very good organization which has made all events to run smoothly. We owe a lot of thanks to Mr. Ibrahim Adam, the responsible Vice-President of ISTRC, and Dr. Francis Ofori and his staff for all the work they have done during the past year. I would like especially to mention the ladies who were, and still are, the good angels behind the scene! Also to be mentioned are those who received us at the airport and the drivers who carried us safely through the town and on our trip to Kumasi. Forgive me if I am not able to enumerate all the events which we have had the pleasure to enjoy. In all, it has been a very successful conference and we all are going home with very good memories of Ghana and its friendly people who gave us a warm welcome.

Thank you very much and see you again soon, if not in Brazil then somewhere else.