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Theor Appl Genet (2010) 121:13391356 DOI 10.1007/s00122-010-1392-8
ORIGINAL PAPER
Location of major effect genes in sorghum (Sorghum bicolor (L.)
Moench)
E. S. Mace D. R. Jordan
Received: 9 December 2009 / Accepted: 14 June 2010 / Published online: 29 June 2010 Springer-Verlag 2010
Abstract Major effect genes are often used for germ-plasm identication, for diversity analyses and as selection targets in breeding. To date, only a few morphological characters have been mapped as major effect genes across a range of genetic linkage maps based on different types of molecular markers in sorghum (Sorghum bicolor (L.) Moench). This study aims to integrate all available previously mapped major effect genes onto a complete genome map, linked to the whole genome sequence, allowing sorghum breeders and researchers to link this information to QTL studies and to be aware of the consequences of selection for major genes. This provides new opportunities for breeders to take advantage of readily scorable morphological traits and to develop more effective breeding strategies. We also provide examples of the impact of selection for major effect genes on quantitative traits in sorghum. The concepts described in this paper have particular application to breeding programmes in developing countries where molecular markers are expensive or impossible to access.
Introduction
Major effect genes are often used for germplasm identication by sorghum breeders and for diversity analysis in germplasm collections, e.g. Upadhyaya et al. (2009); Grenier et al. (2004); Abdi et al. (2002). Major effect genes can also be important as targets for selection in their own right. To date, approximately 35 major effect genes have been mapped in sorghum (Sorghum bicolor (L.) Moench) as simply-inherited markers across a range of genetic linkage maps based on different types of molecular markers. This represents less than 20% of the more than 200 named morphological loci (Doggett 1970). Until recently, the integration of this information has been complicated by the lack of common markers across populations; for example Bennetzen et al. (2001) attempted to place a selection of major effect genes onto a framework map for sorghum, but due to the lack of common markers across the populations available at that time, they were able to map only nine genes and even then with only approximate locations. In the last 5...