Knowledge Center Catalog

Research on Pyrenophora tritici-repentis tan spot of wheat in Uruguay

By: Contributor(s): Material type: TextTextPublication details: Mexico, DF (Mexico) CIMMYT|UCL|BADC : 1998ISBN:
  • 970-648-001-3
Subject(s): DDC classification:
  • 633.1194 DUV
Summary: Tan spot of wheat, first reported in Uruguay in 1982, did not become a major disease until 1990/91 when high disease incidence was noted in the northwestern coastal region of the country. During those years, identification of germplasm with superior disease resistance was not possible due to severe infection levels, although it was possible to distinguish between symptoms of Drechslera tritici-repentis and of Septoria tritici. Almost all cultivars under evaluation were moderately to highly susceptible to tan spot. The perfect stage of the fungus was found on wheat stubble in 1993. Many of the numerous alternative disease hosts reported in the literature are present in Uruguay; however, none have tested positively for tan spot. The increase in zero-tillage cultivation in the country has made it essential to develop and identify highly resistant cultivars. Local advanced breeding lines and introduced germplasm have been screened for tan spot resistance at key locations since 1990. Of these, Fink and other lines were found to be resistant, but Vicam was found susceptible. Careen 12 and Red Chief, sources of tan spot resistance elsewhere, were not adapted to local conditions. Newer germplasm from the region and from CIMMYT, such as Milan, Cisne INIA, Coker62/BR14, LE2062/LE2096, LE2091/LE2089, E.Dor/Aepoglom, and Kvz//BB/Cha/3/Trm/4/TEMU36-78/5/Ovacion, has shown stable resistance over years. Recently, a set of advanced lines from CIMMYT selected for high rainfall conditions has been tested at the seedling stage. Given that disease incidence is related to the amount of stubble present, four commercial cultivars (E. Cardenal, ProlNTA Queguay, Pl. Superior, and INIA Mirlo) were tested for disease development under zero tillage. Disease levels measured (as the area under the disease progress curve, AUDPC) were significantly higher (1363.98) on wheat stubble than on burned wheat stubble (907.34) and oat stubble (366.61). To date, no information on chemical control of tan spot has been locally developed; fungicide for D. tritici-repentis control is applied according to recommendations from Brazil.
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Conference proceedings CIMMYT Knowledge Center: John Woolston Library CIMMYT Publications Collection 633.1194 DUV (Browse shelf(Opens below)) 1 Available R624337
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Tan spot of wheat, first reported in Uruguay in 1982, did not become a major disease until 1990/91 when high disease incidence was noted in the northwestern coastal region of the country. During those years, identification of germplasm with superior disease resistance was not possible due to severe infection levels, although it was possible to distinguish between symptoms of Drechslera tritici-repentis and of Septoria tritici. Almost all cultivars under evaluation were moderately to highly susceptible to tan spot. The perfect stage of the fungus was found on wheat stubble in 1993. Many of the numerous alternative disease hosts reported in the literature are present in Uruguay; however, none have tested positively for tan spot. The increase in zero-tillage cultivation in the country has made it essential to develop and identify highly resistant cultivars. Local advanced breeding lines and introduced germplasm have been screened for tan spot resistance at key locations since 1990. Of these, Fink and other lines were found to be resistant, but Vicam was found susceptible. Careen 12 and Red Chief, sources of tan spot resistance elsewhere, were not adapted to local conditions. Newer germplasm from the region and from CIMMYT, such as Milan, Cisne INIA, Coker62/BR14, LE2062/LE2096, LE2091/LE2089, E.Dor/Aepoglom, and Kvz//BB/Cha/3/Trm/4/TEMU36-78/5/Ovacion, has shown stable resistance over years. Recently, a set of advanced lines from CIMMYT selected for high rainfall conditions has been tested at the seedling stage. Given that disease incidence is related to the amount of stubble present, four commercial cultivars (E. Cardenal, ProlNTA Queguay, Pl. Superior, and INIA Mirlo) were tested for disease development under zero tillage. Disease levels measured (as the area under the disease progress curve, AUDPC) were significantly higher (1363.98) on wheat stubble than on burned wheat stubble (907.34) and oat stubble (366.61). To date, no information on chemical control of tan spot has been locally developed; fungicide for D. tritici-repentis control is applied according to recommendations from Brazil.

English

9806|AGRIS 9802|anterior|R97-98PROCE|FINAL9798

Jose Juan Caballero

CIMMYT Publications Collection


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