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 sorghu m inbred lines, QL39 and QL41. A variety of DNA probes, including sorg hum genomic DNA, maize genomic DNA and cDNA, sugarcane genomic DNA and cDNA, and cereal anchor probes, were screened to identify DNA polymor phism between the parental lines. Using 5 restriction enzymes, probe p olymorphism levels were low (26.5%). A total of 155 restriction fragme nt length polymorphism (RFLP) loci and 8 simple sequence repeat (SSR) loci were mapped onto 21 linkage groups, covering a map distance of ap proximately 1400 cM. Genes for 3 simply inherited traits, awns (AW), m esocarp thickness (Z), and organophosphate insecticide (OPR) reaction, were also mapped. The relationships between this map and other publis hed sorghum maps were reviewed and a comparison of major sorghum RFLP maps attempted. This comparison is expected to enhance the effectivene ss of existing mapping information and will facilitate efforts to map agronomically important traits in sorghum.