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VIEW ARTICLE
Research Reduction in Pycnidial Coverage After Inoculation of Wheat with Mixtures of
Isolates of Septoria tritici. Noga Zelikovitch and Z. Eyal, Department of Botany,
The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv
69978, Israel. Plant Dis. 75:907-910.
Accepted for publication 29 January 1991. Copyright 1991 The American
Phytopathological Society. DOI: 10.1094/PD-75-0907. Inoculation of wheat seedlings with certain combinations of isolates of
Septoria tritici resulted in marked reductions in pycnidial coverage of
leaves compared with plants inoculated separately with individual components of
the mixture. The effect was greater when the isolates were grown together than
when grown separately and mixed before inoculation. The suppression of pycnidial
formation did not depend on the ratio of the isolates in the mixtures. The
addition of a culture filtrate from one isolate to the conidial preparation of
another isolate resulted in marked symptom suppression. In conidial preparations
where the growth medium was decanted and the spores were resuspended in fresh
medium, marked reductions in pycnidial coverages were observed on all cultivars.
These results suggest that S. tritici may produce substances that
regulate the expression of symptoms on wheat leaves inoculated with isolate
mixtures. Challenge inoculations of Kavkaz winter wheat with an isolate several
days after the first inoculation with a different isolate also resulted in
significant reductions in pycnidial coverage. It is possible that a resistant
host response is triggered by the first inoculation. |