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United States Department of Agriculture

Agricultural Research Service

Research Project: ALLIUM, CUCUMIS, AND DAUCUS GERMPLASM ENHANCEMENT, GENETICS, AND BIOCHEMISTRY Title: Molecular mapping of greenbug resistance genes Gb2 and Gb6 in T1AL.1RS wheat-rye translocations

Authors
item Weng, Yiqun
item Lu, Huangjun - TEXAS AGRILIFE RESEARCH
item Rudd, Jackie - TEXAS AGRILIFE RESEARCH
item Burd, John

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 2009
Publication Date: December 23, 2009
Citation: Weng, Y., Lu, H., Rudd, J.C., Burd, J.D. 2009. Molecular mapping of greenbug resistance genes Gb2 and Gb6 in T1AL.1RS wheat-rye translocations. Plant Breeding. 129:472-476.

Interpretive Summary: The greenbug is the important aphid pest of wheat and sorghum in the southern Great Plains of the U.S. At present, Gb3 is the only host resistance gene deployed in wheat field for greenbug resistance, which make have potential risk of being defeated due to emergence of new virulent greenbugs. Two greenbug resistance genes Gb2 and Gb6 derived from the same donor rye line ‘Insave’, are presented in wheat germplasm lines ‘Amigo’ and ‘GRS1201’ respectively as 1AL.1RS wheat-rye translocations. In the present study, molecular mapping of Gb2 and Gb6 was performed in a mapping population derived from the cross between a germplasm line ‘N96L9970’ (Gb6Gb6) and the wheat cultivar ‘TAM 107’ (Gb2Gb2). Segregation analysis of host responses to infestation of two greenbug biotypes E and KS1 in F2:3 plants revealed that Gb2 and Gb6 were two independent but linked loci in 1RS. Linkage analysis showed that Gb2 and Gb6 were 15.8 cM apart with Gb6 being distal to Gb2 in rye chromosome arm 1RS. Eight markers linked with Gb2 and Gb6 were identified. The closest marker, XIA294, was 11.4 cM away from Gb2. Physcial mapping suggested that both Gb2 and Gb6 were located in the satellite region of 1RS.

Technical Abstract: The greenbug, Schizaphis graminum (Rondani), is an important aphid pest of wheat worldwide. Two greenbug resistance genes Gb2 and Gb6 derived from the same donor rye line ‘Insave’, are presented in wheat germplasm lines ‘Amigo’ and ‘GRS1201’ respectively as 1AL.1RS wheat-rye translocations. The allelic relationship between the two genes is unknown, and no molecular markers for Gb6 are available. In the present study, molecular mapping of Gb2 and Gb6 was performed in a mapping population derived from the cross between ‘N96L9970’ (Gb6Gb6) and ‘TAM 107’ (Gb2Gb2). Segregation among F2:3 families of host responses to infestation of two greenbug biotypes E and KS1 revealed that Gb2 and Gb6 were two independent but linked loci in 1RS. Linkage analysis showed that Gb2 and Gb6 were 15.8 cM apart with Gb6 being distal to Gb2 in rye chromosome arm 1RS. Despite the very low degree of polymorphism in the 1RS region between the two parental lines, eight markers linked with Gb2 and Gb6 were identified. The closest marker, XIA294, was 11.4 cM proximal to Gb2. Deletion mapping suggested that both Gb2 and Gb6 were physically located in the satellite region of 1RS.

Last Modified: 10/21/2014
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