Meeting the Challenge of Yellow Rust in Cereal Crops - ICARDA

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Study on resistance reaction of elite barley lines to Puccinia
Striiformis f.sp. hordei in Ardabil
S.A. Safavi 1 and M. Torabi 2
1. Research Centre of Agriculture and Natural Resources of Ardabil, Ardabil, Islamic
Republic of Iran; 2. Seed and Plant Improvement Research Institute, Karaj, Islamic
Republic of Iran
Barley stripe rust (caused by Puccinia striiformis f.sp. hordei) is an important
disease of cultivated barley in several parts of world, and can cause significant
yield losses due to severe epidemics. In Iran, it is increasing on susceptible
cultivars and lines in north-western and northern provinces. In order to
prevent disease epidemics and minimize yield losses, use and production of
resistant lines, particularly with durable resistance, will be the most effective
method of control. For this purpose, 36 barley genotypes in Elite Barley Yield
Trials were evaluated in 2004–2005 in Ardabil. Each line was sown as two 1-m
long rows spaced 30 cm apart. A susceptible cultivar (Afzal or Zarjow) was
planted among the experimental entries at 10-entry intervals and also as
borders for the nursery, which was conducted under natural infection
conditions. In addition, artificial inoculation of the nursery was done using a
mixture of spores and talcum powder at dusk using a duster. Plants were in
the pre-flag-leaf stage. To increase disease development, mist and flood
irrigation were used. At the adult plant stage, infection type (IT) of each entry
was evaluated based on the Roelfs et al. method when disease was well
developed on the susceptible check (70-80S). The percentage leaf area affected
(disease severity) was also scored using the modified Cobb’s scale at the same
time. Coefficients of Infection (CI) were then calculated by combining IT and
disease severity. It was concluded that, for Ardabil entries, 44.4% of genotypes
were resistant (CI = 0–2), 2.8% moderately resistant (CI = 3–4), 13.9%
moderately susceptible (CI = 5–12) and 38.9% susceptible (CI >12). Finally,
61.1% of entries were selected that had CI