Mechanisms of resistance to puccinia recondita in wheat
Mechanisms of resistance to puccinia recondita in wheat
Investigation of resistance components, different phases of the infection process at which resistance operates and mechanisms of resistance may provide information which would be helpful in the search for durable types of resistance to brown rust in wheat, a major considertion in breeding programmes. In monocyclic infection experiments in the glasshouse various components of resistance were investigated at the seedling and adult plant stages in six wheat cultivars exhibiting different reaction types to three brown rust isolates. Urediniospore germination, appressorium formation and penetration were unaffected by cultivar resistance. Partially resistant cultivars exhibited longer latent periods, had smaller colonies with fewer haustorium mother cells, formed fewer and small uredinia and produced fewer urediniospores per unit leaf area or per uredinium than susceptible cultivars. Quantitative histological studies of the host-pathogen interactions showed that the mechanism of resistance was initiated after the formation of the first haustorium mother cells by cessation of hyphal growth and early occurrence of host cell necrosis in hypersensitive reactions or by slowing the rates of colony and uredinial growth in partially resistant cultivars. Reduced colony development was associated with necrosis of some host cells in some cultivar-isolate interactions but it occurred in the absence of necrosis in some other interactions and resulted in lengthened latent periods, smaller uredinia and reduced urediniospore production. The partially resistant cultivars established as many colonies as did susceptible cultivars but higher proportions of early and late aborted colonies in the partially resistant cultivars than in susceptible ones were responsible for the low uredinium density on these cultivars. Although different components of resistance assessed here were usually positively correlated, the existence of some negative correlations indicated that resistance to one component is not always completely correlated with resistance to another. The general implications of these findings in relation to the control of brown rust of wheat are discussed. (DX85729)
University of Southampton
1988
Torabi, Mohammad
(1988)
Mechanisms of resistance to puccinia recondita in wheat.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Investigation of resistance components, different phases of the infection process at which resistance operates and mechanisms of resistance may provide information which would be helpful in the search for durable types of resistance to brown rust in wheat, a major considertion in breeding programmes. In monocyclic infection experiments in the glasshouse various components of resistance were investigated at the seedling and adult plant stages in six wheat cultivars exhibiting different reaction types to three brown rust isolates. Urediniospore germination, appressorium formation and penetration were unaffected by cultivar resistance. Partially resistant cultivars exhibited longer latent periods, had smaller colonies with fewer haustorium mother cells, formed fewer and small uredinia and produced fewer urediniospores per unit leaf area or per uredinium than susceptible cultivars. Quantitative histological studies of the host-pathogen interactions showed that the mechanism of resistance was initiated after the formation of the first haustorium mother cells by cessation of hyphal growth and early occurrence of host cell necrosis in hypersensitive reactions or by slowing the rates of colony and uredinial growth in partially resistant cultivars. Reduced colony development was associated with necrosis of some host cells in some cultivar-isolate interactions but it occurred in the absence of necrosis in some other interactions and resulted in lengthened latent periods, smaller uredinia and reduced urediniospore production. The partially resistant cultivars established as many colonies as did susceptible cultivars but higher proportions of early and late aborted colonies in the partially resistant cultivars than in susceptible ones were responsible for the low uredinium density on these cultivars. Although different components of resistance assessed here were usually positively correlated, the existence of some negative correlations indicated that resistance to one component is not always completely correlated with resistance to another. The general implications of these findings in relation to the control of brown rust of wheat are discussed. (DX85729)
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Published date: 1988
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Local EPrints ID: 460948
URI: http://eprints.soton.ac.uk/id/eprint/460948
PURE UUID: f1e57a4b-b911-4ac4-8708-4bc5f8892a77
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Date deposited: 04 Jul 2022 18:32
Last modified: 04 Jul 2022 18:32
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Author:
Mohammad Torabi
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