· ~ -.. ~ ;,:') rrin '"!?Ir)l :. . . ; . . : .J'. , ; ., n # • • • :. ' ~ • LJ J . '!i.· •• 1: 2 1 JUL 1992 Ill i l.lr:s\:/L.:Ju u L::J~ --·-·····------

Proceedings of a Workshop Rabat, Morocco, 19-21 November 1989

A. Comeau K.M. Makkouk editors

International Center for Agricultural Research in the Dry Areas ( ;c~ r.)i_:r>-- :r_,:;. : : ·; 1 '1 I 1 ~~' ._ .. ,_~r ·r'\~ : • 1 ~ t .. : ' I ; ~ t; : { ~ I '' .l l1 : 1 \ : ·-1{: ._I~st~bijsJ:n:d ·i6It91:1rthe International Center for Agricultural Research in the Dry -r ,,__ Ar_«.~&.(ICARDA) -is governed by an independent Board of Trustees. Based at Aleppo, Syria, it is one of 16 centers supported by the Consultative Group on International Agricultural Research (CGIAR), which is an international group of representatives of donor agencies, eminent agricultural scientists, and institutional administrators from developed and developing countries who guide and support its work.

The CGIAR seeks to enhance and sustain food production and, at the same time, improve socioeconomic conditions of people, through strengthening national research systems in developing countries.

!CARDA focuses its research efforts on areas with a dry summer and where precipitation in winter ranges from 200 to 600 mm. The Center has a world responsibility for the improvement of , lentil, and faba bean, and a regional responsibility-in West Asia and North Africa-for the improvement of , chickpea, and pasture and forage crops and the associated farming systems.

Much of ICARDA's research is carried out on a 948-hectare farm at its headquarters at Tel Hadya, about 35 km southwest of Aleppo. !CARDA also manages other sites where it tests material under a variety of agroecological conditions in Syria and Lebanon. However, the full scope of ICARDA's activities can be appreciated only when account is taken of the cooperative research carried out with many countries in West Asia and North Africa.

The results of research are transferred through ICARDA's cooperation with national and regional research institutions, with universities and ministries of agriculture, and through the technical assistance and training that the Center provides. A range of training programs are offered extending from residential courses for groups to advanced research opportunities for individuals. These efforts are supported by seminars, publications, and by specialized information services. F tPRC- Lib L Barley Yellow Dwarf in West Asia and North Africa

Proceedings of a workshop organized by the International Center for Agricultural Research in the Dry Areas (ICARDA) and International Development Research Centre (IDRC) held in Rabat, Morocco, 19-21 November 1989

Editors

A. Comeau Agriculture Canada Research Station Quebec, Canada

K.M. Makkouk International Center for Agricultural Research in the Dry Areas Aleppo, Syria

REC'D. I REçU

21 1992 IDR( - AFNS -

International Center for Agricultural Research in the Dry Areas ICARDA P.O. Box 5466, Aleppo, Syria

-. Published by ICARDA, 1992 Edited and designed by: Sayce Publishing, Exeter, United Kingdom

The views expressed in these proceedings are those of the authors and not necessarily of the sponsors. Also, the mention of trade names does not imply endorsement of or discrimination against any product by the sponsors. Foreword

In recent years, widespread infections of cereals with barley yellow dwarf virus (BYDV) in North Africa have attracted some attention among research and extension workers. As work on cereal virus diseases in the region is fairly limited, the International Center for Agricultural Research in the Dry Areas (ICARDA), in collaboration with Agriculture Canada and Laval University and with the full support of the International Development Research Centre (IDRC), organized a workshop on BYDV in Rabat, Morocco, in November 1989 to bring together scientists from the West Asia and North Africa (WANA) region with those from other institutions worldwide. The main objective of the workshop was to discuss the latest research developments and how to make use of them in formulating future research on BYDV in the WANA region in general and in North Africa in particular, where BYDV is causing serious losses in cereal crops. Future collaboration between ICARDA, Agriculture Canada, Laval University, Chile and scientists of the national programs in North African countries was also discussed at the workshop. The contributions of all scientists who presented their findings at the workshop are included in this volume. Collectively, the papers provide ample coverage of BYDV and the promising approaches which should be considered in efforts to limit the spread of the virus and minimize the losses it causes. ICARDA greatly appreciates the assistance given by the IDRC in sponsoring the workshop and financing this publication. The proceedings represent a valuable contribution to the knowledge about BYDV in the WANA region and are indicative of the regional and international cooperation targeted towards solving a problem of economic importance to several countries of the region served by ICARDA.

NASRAT R. FADDA Director General, ICARDA

111

Preface

Meetings dealing with barley yellow dwaff virus (BYDV) are still something of a novelty. This aphid-borne affecting all cereal species was described as early as 1951, but only since enzyme-linked immunosorbent assay (ELISA) test kits became commercially available has BYDV received serious attention. The 1987 meeting on BYDV organized by the Centro Internacional de Mejoramiento de MaIz y Trigo (CIMMYT) in Italy attracted over 100 scientists, indicating the interest generated by these recent developments. We are still breaking new ground in developing new methods, establishing traditions and increasing general awareness of the need for research on . Notwithstanding the usual caution about generalizations, it must be said that although a number of cereal crop problems have been solved during the past 50 years, the BYDV problem has, if anything, worsened. The reasons for this are not always clear or well documented, even in North America. Work in South America, where the BYDV problem erupted quite suddenly during the 1970s, shows that a concerted research effort does pay dividends. Strong local commitment in Chile and Brazil supported plant breeding, crop management and biological control research and, within a decade, this resulted in the creation of new cultivars and the introduction of aphid parasites, leading to a reduction in yield losses. Successful BYDV management through plant breeding has also been demonstrated in California, USA with the development of some barley cultivars and in other North American regions with the develop- ment of cultivars. The choice of Rabat, Morocco as the venue for this meeting was very appropriate, as this part of North Africa is one area where the BYDV problem is now known to have economic importance. We extend our sincere thanks to the Moroccan scientists and staff of the International Center for Agricultural Research in the Dry Areas (ICARDA) based in Morocco for making the local arrangements for the meeting and to the numerous scientists from many countries who accepted the challenge of bringing everyone up to date on the status of BYDV and on current research aimed at its control. It is also fitting to mention the pioneer role of the International Development Research Centre (IDRC) in financially supporting the research upon which much BYDV control is based. This was done through the breeding of virus-tolerant cereals, for which the international project at Laval University, Canada shared responsibility for a decade with ICARDA and Chilean scientists. Additional work on aphid resistance was done in Egypt by ICARDA and Egyptian scientist