Knowledge Center Catalog

Broad based genetic resistance to tan spot of wheat in CIMMYT germplasm

By: Contributor(s): Material type: TextTextPublication details: Mexico, DF (Mexico) CIMMYT : 2011Description: p. 91ISBN:
  • 978-970-648-180-1
Summary: Tan spot, incited by the ascomycete fungus Pyrenophora tritici-repentis (Died.) Drechs, is a major foliar disease of wheat. Pyrenophora tritici-repentis induces two distinct symptoms on susceptible wheat cultivars, tan necrosis and extensive chlorosis. Tan spot causes on average yield losses of 5-10%, however under conditions favourable for disease development losses can be higher than 50%. Significant reduction in grain quality is manifested by tan spot due to grain shriveling, red smudge and black point. Conservation agriculture in combination with wheat monoculture involving cultivation of susceptible cultivars has resulted in frequent onset of tan spot epidemics worldwide. Increasing temperatures and drought due to climate change could result in a higher degree of leaf senescence which is likely to further increase tan spot severity. Development of resistant cultivars, in conjunction with crop rotation, will provide an effective, economical, and environmentally safe means of controlling tan spot. CIMMYT, Mexico in collaboration with SLU, Sweden has initiated major efforts to mitigate the threat of tan spot. Efforts include large scale screening of wheat germplasm under traditional seedling and hydroponic tests and association analysis for identification of genomic regions contributing to resistance. Screening experiments reveal that CIMMYT's elite bread wheat germplasm has a high level of resistance to tan spot caused by P. tritici-repentis race 1. Resistant breeding lines have diverse genetic make-up and the resistance is likely broad based. Association mapping studies done with CIMMYT germplasm reconfirmed that, in addition to the previously identified genomic regions contributing to tan spot resistance, CIMMYT germplasm has novel genomic regions on the long arm of chromosomes 6A and 7B for tan spot resistance. Efforts are being made to incorporate this broad genetic resistance into modern wheat cultivars.
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Abstract only

Tan spot, incited by the ascomycete fungus Pyrenophora tritici-repentis (Died.) Drechs, is a major foliar disease of wheat. Pyrenophora tritici-repentis induces two distinct symptoms on susceptible wheat cultivars, tan necrosis and extensive chlorosis. Tan spot causes on average yield losses of 5-10%, however under conditions favourable for disease development losses can be higher than 50%. Significant reduction in grain quality is manifested by tan spot due to grain shriveling, red smudge and black point. Conservation agriculture in combination with wheat monoculture involving cultivation of susceptible cultivars has resulted in frequent onset of tan spot epidemics worldwide. Increasing temperatures and drought due to climate change could result in a higher degree of leaf senescence which is likely to further increase tan spot severity. Development of resistant cultivars, in conjunction with crop rotation, will provide an effective, economical, and environmentally safe means of controlling tan spot. CIMMYT, Mexico in collaboration with SLU, Sweden has initiated major efforts to mitigate the threat of tan spot. Efforts include large scale screening of wheat germplasm under traditional seedling and hydroponic tests and association analysis for identification of genomic regions contributing to resistance. Screening experiments reveal that CIMMYT's elite bread wheat germplasm has a high level of resistance to tan spot caused by P. tritici-repentis race 1. Resistant breeding lines have diverse genetic make-up and the resistance is likely broad based. Association mapping studies done with CIMMYT germplasm reconfirmed that, in addition to the previously identified genomic regions contributing to tan spot resistance, CIMMYT germplasm has novel genomic regions on the long arm of chromosomes 6A and 7B for tan spot resistance. Efforts are being made to incorporate this broad genetic resistance into modern wheat cultivars.

Genetic Resources Program|Research and Partnership Program|Global Wheat Program

English

Lucia Segura

INT1237|CCJL01|INT2868|INT0610

CIMMYT Staff Publications Collection


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