Meeting the Challenge of Yellow Rust in Cereal Crops - ICARDA

2000 masl; Ae. cylindrica is located in middle highlands and valleys up to
1800 masl; and Ae. tauschii is distributed everywhere from 360 to 2000 masl.
The genus Aegilops is closely related to the genus Triticum, and its value as a
source of genetic improvement of wheat is well documented. The diploid
Ae. tauschii is the D-genome donor to hexaploid wheat, Triticum aestivum
(AABBDD). The level of genetic variation in the D genome of Ae. tauschii is
extensive. Ae. tauschii contains more genetic variability for diseases and insect
resistance, isozymes, and seed storage protein than the D genome of
T. aestivum. Microsatellite analysis of Ae. tauschii germplasm has been studied
by estimating the genetic relation between 113 accessions from the genebank
collection at IPK, Gatersleben, Germany. Microsatellite markers developed
from T. aestivum and Ae. tauschii sequences showed a high level of
polymorphism. All accessions from various regions could be distinguished
and clustered according to their taxonomic classification and their
geographical distribution. Ae cylindrica (genome CD) is one of the wild wheat
species that could serve as a genetic resource for resistance against the rusts.
To use Ae. cylindrica efficiently in breeding programmes, detailed knowledge
of homoeology between this wild species and hexaploid wheat would be
helpful. Ae. triuncialis (genome UC) is another wild wheat species that is a
potential source of resistance to yellow rust.
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Improvement of drought tolerant winter and facultative
wheat promising lines resistant to yellow and stem rusts
(Ug99)
S. Mahfoozi and F. Afshari
Department of Cereal Research, Seed and Plant Improvement Institute (SPII), Karaj,
Islamic Republic of Iran
Yellow rust (Puccinia striiformis f.sp. tritici) and stem rust (P. graminis) diseases
of wheat are significant threats to wheat production, even in drought-stressed
regions of Iran. Although research efforts have effectively reduced crop
damage, rust populations continue to evolve due to changes in the
environment and the wheat production system in the region. Pathogenic
variation is the underlying reason for the elusiveness of rust resistance. A new
yellow rust race (166E134A+, Yr27+) spread widely in Iran in 2006/07 and
caused damage to most wheat cultivars grown. For stem rust epidemics, an
emerging new race (Ug99) in Africa and its spread to neighbouring countries
such as Yemen (2006) and Iran (2007) is also a big threat for wheat production.