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Mapping of New Sources of Resistance to Puccinia graminis f. sp. tritici Race Ug99

By: Bhavani, S.
Contributor(s): Jin, Y [coaut.] | Singh, D [coaut.] | Huerta-Espino, J [coaut.] | Singh, R.P [coaut.].
Material type: materialTypeLabelBookAnalytics: Show analyticsPublisher: 2009Description: p. 15.Summary: One of the best approaches to alleviate the threat from Puccinia graminis tritici race Ug99 (TTKSK) is to identify and characterize sources of resistance within the available wheat (Triticum aestivum) breeding materials and commercial cultivars. Genes identified can then be deployed in combinations. Identification of molecular markers tightly linked to resistance genes can aid their pyramiding, and allow selection of plants without the need for disease screening. This is especially important with Ug99 and its derivatives, which are absent in many countries. F3 and F4 populations derived from the crosses of susceptible PBW343 with three resistant parents with race-specific resistance genes were developed and characterized for reaction to TTKSK in the greenhouse at USDA-ARS CDL, St. Paul, MN; and, during 2008, in the field at Njoro, Kenya, where the Sr24virulent Ug99 variant. Bulk-segregant analysis was performed to identify marker trait associations and the linked markers were used for genotyping lines clearly identified in field trials as homozygous resistant and homozygous susceptible. Genomic regions with 3 putative new resistance genes, temporarily designated as SrA, SrB and SrC were identified. Gene SrA was mapped on chromosome 3DL (linked markers, Xgwm52, Xgwm341) of Milan/Sha7/3/Thb/CEP7780//Sha4/Lira/4/Sha4/ Chil, SrB on chromosome 3BS (Xgwm566, Wmc231) of Ning9415/3/Ures/Bow//Opata/4/Ningmai 7, and SrC on chromosome 5DL (Xgwm292, Xgwm212) of Chen/ Ae.Sq//2*Weaver/3/Oasis/5*Borl95. Like several other characterized stem rust resistance genes, the three new resistance genes provide moderate levels of resistance at the seedling and adult stages. Further studies to confirm the results and development of targeted mapping populations to identify closely linked markers are under progress.Collection: CIMMYT Staff Publications Collection
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Conference proceedings CIMMYT Knowledge Center: John Woolston Library

Lic. Jose Juan Caballero Flores

 

CIMMYT Staff Publications Collection CIS-5814 (Browse shelf) Available
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Poster Abstract

One of the best approaches to alleviate the threat from Puccinia graminis tritici race Ug99 (TTKSK) is to identify and characterize sources of resistance within the available wheat (Triticum aestivum) breeding materials and commercial cultivars. Genes identified can then be deployed in combinations. Identification of molecular markers tightly linked to resistance genes can aid their pyramiding, and allow selection of plants without the need for disease screening. This is especially important with Ug99 and its derivatives, which are absent in many countries. F3 and F4 populations derived from the crosses of susceptible PBW343 with three resistant parents with race-specific resistance genes were developed and characterized for reaction to TTKSK in the greenhouse at USDA-ARS CDL, St. Paul, MN; and, during 2008, in the field at Njoro, Kenya, where the Sr24virulent Ug99 variant. Bulk-segregant analysis was performed to identify marker trait associations and the linked markers were used for genotyping lines clearly identified in field trials as homozygous resistant and homozygous susceptible. Genomic regions with 3 putative new resistance genes, temporarily designated as SrA, SrB and SrC were identified. Gene SrA was mapped on chromosome 3DL (linked markers, Xgwm52, Xgwm341) of Milan/Sha7/3/Thb/CEP7780//Sha4/Lira/4/Sha4/ Chil, SrB on chromosome 3BS (Xgwm566, Wmc231) of Ning9415/3/Ures/Bow//Opata/4/Ningmai 7, and SrC on chromosome 5DL (Xgwm292, Xgwm212) of Chen/ Ae.Sq//2*Weaver/3/Oasis/5*Borl95. Like several other characterized stem rust resistance genes, the three new resistance genes provide moderate levels of resistance at the seedling and adult stages. Further studies to confirm the results and development of targeted mapping populations to identify closely linked markers are under progress.

Global Wheat Program

English

Lucia Segura

INT2843|INT0610

CIMMYT Staff Publications Collection

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