Construction of a genetic map in a sorghum recombinant inbred line using probes from different sources and its comparison with other sorghum maps

A genetic map was established using 120 F-5 sorghum recombinant inbred lines (RILs) developed from a cross between 2 Australian elite sorghum inbred lines, QL39 and QL41. A variety of DNA probes, including sorghum genomic DNA, maize genomic DNA and cDNA, sugarcane genomic DNA and cDNA, and cereal anchor probes, were screened to identify DNA polymorphism between the parental lines. Using 5 restriction enzymes, probe polymorphism levels were low (26.5%). A total of 155 restriction fragment length polymorphism (RFLP) loci and 8 simple sequence repeat (SSR) loci were mapped onto 21 linkage groups, covering a map distance of approximately 1400 cM. Genes for 3 simply inherited traits, awns (AW), mesocarp thickness (Z), and organophosphate insecticide (OPR) reaction, were also mapped. The relationships between this map and other published sorghum maps were reviewed and a comparison of major sorghum RFLP maps attempted. This comparison is expected to enhance the effectiveness of existing mapping information and will facilitate efforts to map agronomically important traits in sorghum.