Meeting the Challenge of
Yellow Rust in Cereal Crops
Proceedings of the 2nd, 3rd and 4th
Regional Conferences on Yellow Rust
Central and West Asia and North Africa (CWANA) Region
Amor Yahyaoui and Sanjaya Rajaram
ICARDA International Center for Agricultural Research in the Dry Areas
ICARDA welcomes comment and feedback on this publication. See Web site and e-mail below.
Key words: yellow rust; leaf rust; stem rust; wheat; Central Asia; West Asia; North Africa;
International Center for Agricultural Research in the Dry Areas (ICARDA) P.O. Box 5466, Aleppo, Syria.
Tel: (963-21) 2213433
Fax: (963-21) 2213490
E-mail: [email protected]
Web site: www.icarda.org
The views expressed are those of the authors, and not necessarily those of ICARDA. Where trade names are used, it does not imply endorsement of, or discrimination against, any product by the Center. Maps have been used to support research data, and are not intended to show political boundaries.
Copyright 2012 ICARDA (International Center for Agricultural Research in the Dry Areas) All rights reserved.
ICARDA encourages fair use, sharing and distribution of this information for non-commercial purposes, with proper attribution and citation.
Wheat is grown on roughly 230 million hectare worldwide, with 650 million tonne of grain produced each year. It is the main food staple in many countries, particularly in Central Asia, West Asia and North Africa (the CWANA region), which has the worlds highest per capita wheat consumption. Wheat is grown on 50 million hectare across CWANA, but average productivity in the region is only 1.5 t/ha, half the global average.
Wheat has its origin in West Asia, most likely in the Fertile Crescent, where productivity can be very high. However, the region also suffers from heavy periodic incidence of diseases and insect pests that cause heavy crop losses. The most important wheat diseases in CWANA are rusts, mildew, foliar blights and bunts. Among the rusts, yellow (stripe) rust is the most serious in CWANA, and perhaps globally. The world's wheat supplies are under threat from fast-mutating new strains of stripe [yellow] rust. The new strains (pathotypes) attack hitherto resistant varieties. They are also spreading to new areas as they have adapted to higher temperatures.
Millions of tonnes of wheat have been lost due to pandemics of stripe rust across CWANA countries. In the 200910 season, an epidemic of stripe rust swept across West and Central Asia. Syria lost nearly half of its wheat harvest in 2010. The growing threat to food security, affecting countries in CWANA that are already partially dependent on food imports, is being met with new research initiatives, led by international agencies such as ICARDA, CIMMYT and FAO in collaboration with National Agricultural Research Systems (NARS).
The first steps in combating stripe rust will be to document the geographical extent and scale of losses; share research findings and breeding material; and develop regional, multi-country, multi-institution partnerships for disease surveillance, monitoring and control.
In the last 10 years, ICARDA and its partner NARS have organized 4 international stripe rust conferences, held in Iran, Pakistan, Uzbekistan and Turkey. Hundreds of stripe rust scientists presented their findings, and shared ideas and experiences to help develop effective, broad-based strategies to reduce disease losses, predict future outbreaks, and restrict the spread of new stripe rust pathotypes. This publication summarizes the findings of the last three conferences. It includes scientific papers and abstracts covering various aspects of stripe rust monitoring, management, resistance breeding, chemical control and epidemiology.
These publications present a comprehensive view of stripe rust management and control. They are expected to be of value to rust researchers, as well as agricultural development planners, policy-makers and farmers in CWANA countries and perhaps globally.
Director General, ICARDA
The Central and West Asia and North Africa (CWANA) countries grow wheat on over 50 million hectare that are constantly at high risk of yellow rust attack. Several countries rely primarily on wheat production for their food security and livelihood. Together, these account for over 30% of the global wheat production area. Wheat is the staple food crop, providing on average some 40% of per capita calories, and is an important commodity in the diets of the people of the CWANA. The epidemic of the late 1980s resulted in cost of several millions in terms of crop loss and fungicide costs. Another epidemic occurred in CWANA in the 1990s. The most recent epidemic, in 2009/10, was mostly associated with the breakdown of resistance of the Yr27 gene and has had devastating effects on wheat production in CWANA. The breakdown of Yr27 was reported in 2004 by several authors in these proceedings and other publications.
A regional yellow rust conference for Central Asia and North Africa (YRC) was launched by ICARDA and SPII, Iran, in 2001. That [First] Regional Yellow Rust Conference for Central and West Asia and North Africa was held at Karaj, Iran, from 8 to 14 May 2001. The objective of the YRC was to focus on regional issues associated with yellow rust, to exchange scientific information and to plan collaborative activities. The researchers welcomed the organization of such a targeted conference and agreed to hold one every 3 years within the CWANA region. The proceeding of the first YRC was published under the title: Meeting the Challenge of Yellow Rust in Cereal Crops. The proceeding of the following three conferencesheld in Pakistan, Uzbekistan and Turkeyare assembled here based on the information provided by conference participants.
Yellow Rust continues to be the most widespread and important bread wheat disease in CWANA countries. The known resistance genes are becoming ineffective against new, evolving races that are rapidly spreading across the region. Despite the commitment and ongoing breeding programmes to achieve resistance to yellow rust, severe epidemics with substantial losses have been reported in Australia, China, India and USA in the last decade.
The commercially grown wheat varieties are highly susceptible to new pathotypes of yellow rust. Detection of pathogen variation using a series of host differentials has been valuable in providing important insights into the evolution of pathotypes in response to selection pressure imposed by the host resistance genes. Breeding for resistance, and the parallel requirement to monitor pathogen populations, will continue to form the long-term strategy for yellow rust control.
The long-term solutions to yellow rust epidemics in CWANA, and perhaps globally, reside in concerted strategies and sustained funding of integrated projects on: (1) surveillance and rapid response; (2) crop breeding based on durable resistance and gene diversity; (3) scaling-up of resistant varieties and dynamic seed production programmes; (4) sharing of information, such as through these proceedings; and (5) capacity building.
Dr Amor Yahyaoui Dr Sanjaya Rajaram
Joint Scientific Editors
About this publication
This volume contains the Proceedings of three regional conferences addressing rust diseases, principally yellow [stripe] rust of wheat, but also addressing leaf and stem rusts of wheat and rusts on barley. The geographical focus is the swathe of countries stretching from India in the east, across Central and West Asia, the Caucasus, the Horn of Africa and North Africa to Morocco in the west. The three conferences are: Second Regional Conference on Yellow Rust in the Central and West Asia and North Africa (CWANA) Region, held in Islamabad, Pakistan, 2226 March 2004. See pages 1144. Third Regional Conference on Yellow Rust in the Central and West Asia and North Africa (CWANA) Region, held in Tashkent, Uzbekistan, 811 June 2006. See pages 145238. Fourth Regional Yellow Rust Conference for the Central and West Asia and North Africa (CWANA) Region, held in Antalya, Turkey, 1012 October 2009. See pages 239412.
The Second Regional Yellow Rust conference for the CWANA region was jointly organized by Pakistan Agricultural Research Council (PARC), ICARDA and CIMMYT. Major funding for this conference was provided by DANIDA (Denmark) and ACIAR (Australia), with important contributions from ICARDA, CIMMYT and the Government of Pakistan. We thank the organizers, and the Institutions who provided needed funding to bring more than 100 scientists from 12 countries to attend this conference in Islamabad (1622 March 2004). Appreciation goes to colleagues who helped edit papers of this conference, particularly Dr Ahmad Iftikhar and Dr Anjum Munir from NARC (Pakistan), Dr Habib Ketata from ICARDA and Dr Mogens Hovemoller from DIAS (Denmark).
The Third RYC was organized by the Uzbek-Ministry of Agriculture, ICARDA and CIMMYT, with great assistance from PFU. The conference was sponsored by Arab Fund (AFSED) and ACIAR (Australia), with important contributions from ICARDA and CIMMYT. The Conference was organized a year earlier than originally planned in response to the threat from Ug99 and the establishment of BGRI. The conference was held in Tashkent (Uzbekistan) from 8 to 11 June 2006, and was attended by over 70 participants from 17 countries.
The Fourth RYC was held in Antalya (Turkey) from 1