Meeting the Challenge of Yellow Rust in Cereal Crops - ICARDA

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Investigation of genetic resistance to yellow rust disease in
some wheat cultivars
A.R. Souhani Darban 1 and A.R. Razavi 2
1. Department Agriculture. Azad University Branch Mashhad, Islamic Republic of
Iran; 2. Agricultural and Natural Resources Research Centre, Khorasan Razavi,
Mashhad, Islamic Republic of Iran
Yellow rust caused by Puccinia striiformis f.sp. tritici is an important disease of
wheat in many regions of the world. In Iran, severe epidemic of the disease
occurred in 1993 and 1995. In our study, we conducted a genetic analysis of
crosses involving eight cultivars (three resistant, three moderately resistant
and two susceptible). The eight cultivars were crossed in half diallel. The
plants of the parents, F 1, F 2, BC 1 and BC 2 were inoculated with race 4EOA+.
Pustule size and pustule density were measured The experiment was
conducted in the greenhouse. The chosen experimental design was a
randomized complete block with three replications. Genetic analysis and
heritability of partial resistance were determined using the method of Griffing
and Haymans. The analysis of variance showed both additive genetic variance
and dominance in different cultivars. MS(GCA)/MS(SCA) ratio for both traits
were significant. The most important of the additive variance ratio is nonadditive
variance. Mean degree of dominance for the traits pustule size and
density were calculated to be 1.119 and 0.8, respectively. The three parameters
m, [d] and [h] are significant. Interaction dominance × dominance for traits
was significant.
Recognition of four subspecies of Puccinia striiformis and
development of real-time PCR detection assays
M. Liu and S. Hambleton
Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada,
Ottawa, Canada
In recent years, the incidence of yellow rust of wheat has increased in the USA
and Canada, causing substantial losses. Early detection and differentiation
from other wheat diseases is important for initiating appropriate pest
management measures. Monitoring of air-borne spore dispersal can provide