Euphytica (2009) 165:597–606 DOI 10.1007/s10681-008-9791-5 123 Molecular mapping of Cg1, a gene for resistance to anthracnose (Colletotrichum sublineolum) in sorghum R. Perumal · M. A. Menz · P. J. Mehta · S. Katilé · L. A. Gutierrez-Rojas · R. R. Klein · P. E. Klein · L. K. Prom · J. A. Schlueter · W. L. Rooney · C. W. Magill Received: 18 July 2008 / Accepted: 11 August 2008 / Published online: 26 August 2008  Springer Science+Business Media B.V. 2008 Abstract Anthracnose, caused by the fungus Col- letotrichum sublineolum is one of the most destruc- tive diseases of sorghum and has been reported in most areas where the crop is grown. Several control strategies have been developed but host plant resis- tance has been regarded as the most eVective strategy for disease control. Here, we describe the search for molecular markers that co-segregate with Cg1, a dominant gene for resistance originally identiWed in cultivar SC748-5. To identify molecular markers linked with the Cg1 locus, F 2:3 plants derived from a cross to susceptible cultivar BTx623 were analyzed with 98 AFLP primer combinations. BTx623 was chosen as the susceptible parent because it is also one on the parents used in creating RFLP and AFLP maps and BAC libraries for sorghum. Four AFLP markers that cosegregate with disease resistance were identi- Wed, of which Xtxa6227 mapped within 1.8 cM of the anthracnose resistance locus and all four AFLP mark- ers have been previously mapped to the end of sor- ghum linkage group LG-05. Sequence scanning of BAC clones spanning this chromosome led to the dis- covery that Xtxp549, a polymorphic simple sequence repeat (SSR) marker, mapped within 3.6 cM of the anthracnose resistance locus. To examine the eYcacy of Xtxa6227 and Xtxp549 for marker-assisted selec- tion, 13 breeding lines derived from crosses with sorghum line SC748-5 were genotyped. In 12 of the 13 lines the Xtxa6227 and Xtxp549 polymorphism associated with the Cg1 locus was still present, suggesting that Xtxp549 and Xtxa6227 could be use- ful for marker-assisted selection and for pyramiding of Cg1 with other genes conferring resistance to C. sublineolum in sorghum. Keywords Anthracnose disease · Molecular markers · Genetic Map · BAC R. Perumal · S. Katilé · C. W. Magill (&) Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843-2182, USA e-mail: c-magill@tamu.edu M. A. Menz · L. A. Gutierrez-Rojas · W. L. Rooney Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas 77843-2474, USA Present Address: M. A. Menz Syngenta Seeds S.A.S., 12 Chemin de L’Hobit, 31790 Saint-Sauveur, France P. J. Mehta Monsanto, 1677 80th street, Monmouth, IL 61462, USA R. R. Klein · L. K. Prom USDA-ARS, Southern Plains Agricultural Research Center, College Station, Texas 77845, USA P. E. Klein Department of Horticultural Sciences and Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, Texas 77843-2123, USA J. A. Schlueter USDA-ARS, Corn Insects and Crop Genetics Research Unit, Ames, Iowa 50011, USA