TABLE CONTENTS

SESSION FORTY-SIX – CEREAL AND POTATO CYST NEMATODES
CONVENORS: SUE TURNER & JAVIER FRANCO PONCE
An Overview of the Status of Cereal Cyst Nematodes on Wheat and their
Management through Host Plant Resistance
Nicol J.M. (1) & R. Rivoal (2)
(1) CIMMYT (International Maize and Wheat Improvement Centre), ICARDA-CIMMYT Wheat Improvement
Program . P.O. Box. 39 Emek 06511 Ankara, Turkey; (2) Biologie des Organismes et des Populations
appliquée à la Protection des Plantes (BiO3P), UMR INRA/ENSAR, BP 35327, 35653 Le Rheu,
France (now retired).
On wheat three main species are documented to be the most economically important:
Heterodera avenae, H. filipjevi and H. latipons which belong to the cereal cyst nematode
complex. H. avenae is the most widely distributed species being found in less temperate
regions throughout the world. H. latipons is essentially only Mediterranean in distribution,
however, has also been found in northern Europe and Iran. H. filipjevi, formerly know as
Gotland strain of H. avenae appears to be found in more continental climates but also Greece
and India.
Yield losses caused by these three species on wheat range from 15-96% in various studies
conducted around the world. Greater yield losses are found where drought conditions prevail
in sandy soils, and with wheat monoculture cropping systems, which are commonly practised
through North Africa and Western Asia.
Although rotation with non-cereals offers an effective control method, in many countries this
option is limited. The most economically and environmentally sustainable option is the use
of host genetic resistance in wheat. However, CCN is complex with several species and
pathotypes within species. To date nine single dominant genes known as Cre genes have
been identified in wheat and its wild relatives (Aegilops spp.), however their effectiveness is
dependent the species and pathotypes prevailing in a given region. Effective control through
host genetic resistance has been achieved in Australia with the release of commercially
resistant cultivars. Work in many other countries has also identified new sources of
resistance and effective genes, and some of these have been deployed in breeding programs
(eg Raj1 in India). A newly formed initiative known as the International Cereal Cyst
Nematode Initiative (ICCNI) has been established in 2007 with CIMMYT, several leading
ARIs and NARs partners including Turkey and China to work collectively on greater
understanding and sustainable control of CCN on wheat.
5 th International Congress of Nematology, 2008 168