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Additional Sources of Resistance to Tan Spot of Wheat
Author(s) -
Riede C. R.,
Francl L. J.,
Anderson J. A.,
Jordahl J. G.,
Meinhardt S. W.
Publication year - 1996
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1996.0011183x003600030040x
Subject(s) - germplasm , biology , seedling , cultivar , cochliobolus sativus , pyrenophora , inoculation , leaf spot , spots , agronomy , poaceae , conidium , horticulture , plant disease resistance , botany , gene , biochemistry
Tan spot, a foliar disease of wheat ( Triticum aestivum L. em Thell) and durum ( T. turgidum var. durum L.) caused by Pyrenophora triticirepentis (Died.) Drechs., reduces yield in susceptible cultivars by 3 to 50%. Additional sources for resistance to tan spot were sought in germplasm consisting of a collection of spring wheats previously screened for reaction to spot blotch [ Cochliobolus sativus (Ito & Kurib.) Drech. ex Dastur] in Brazil, wheat cultivars recommended for cultivation in the state of Paraná, Brazil, and a collection of synthetic hexaploid wheats. Plants from each of the three groups were inoculated at the seedling stage with a composite of four fungal isolates and at the adult stage with one of the four isolates. A subset of germplasm was treated at the seedling stage with necrosis toxin, crude extract, and conidia produced by P. tritici‐repentis isolate 86‐124. Adult disease reactions did not always agree with seedling evaluations and some of the variation could be explained by sensitivity or a mixed reaction to necrosis toxin. Assay with purified necrosis toxin was a reliable way to detect a major factor involved in resistance. This work identifies diverse germplasm available for incorporation of tan spot resistance into cultivated wheats.