Different physiological races of Puccinia striiformis were identified in North Delia during two successive seasons The races 2E22. I34E150. 174FI58. 6EI8. J34E158 and 238E190 were identified in 1999/2000 season whereas the races 2E0.6F.0. 6E1X. 174FI58. 134E158, 23KEI90 and 23IE223 were identified in 2000/2001 season. Race I34EI58 exhibited the highest frequency during the two seasons. Race 238EI90 was found only on infected spikes of wheat cv. Sakha-69 during (lie two seasons Wheal cultivars Sakha-8. Sakha-69.
Gemmeiza-3, Gemineiza-5, Sids-7 and Sids-9 exhibited susceptible reaction when inoculated with race 238E190 under field conditions whereas Sakha-93. Giza-168, Genuneiza-9 and Sids-1 were resistant. Infection with race 238EI90 significantly reduced the yield and yield components of the first cultivars compared with control (sprayed with Sumi-8 fungicide) Disease losses in yield and yield components were significantly higher in Sids-7 and Sids-9 compared with Gemmeiza-3 and Gemmeiza-5 cvs.
The reaction of the tested wheal cultivars to infection with stripe rust was varied depending on plant growth stage and the surrounding temperature regimes. AH tested wheat cultivars were generally more sensitive to infection at 8-l5°C than at the higher temperature regime (14-28°C) and at seedling stage than at the adult growth stages (stem elongation, booting and heading) The recorded infection type at the higher temperature regime was varied and increased toward susceptibility when the tested plants were later transferred to the low
temperature regime. .
Spraying plants of wheat cv. Giza-100 at seedling and adult stages (24 h before rust inoculation) with (he crude leaves extract of Eucalyptus robusta. Mvoporum pictum and Salix babylonica was controlled the stripe rust infection through elongating the latent period (29-30 days) compared with the control (12 days). Efficiencies of these extracts were greatly decreased when used 0 days after rust inoculation However, the Sumi-8 fungicide was the best foliar treatment for elongating the latent period (35.3-38.7 days). |
