Random-amplified-polymorphic DNA markers in sorghum

Conditions have been identified that allow reproducible amplification of RAPD markers in sorghum. High resolution of RAPD markers was accomplished by radiolabeling PCR-amplified DNAs followed by separation on denaturing 5% polyacrylamide gels. Reaction parameters including MgCl₂ concentration and temperature significantly influenced yield and the type of amplification products synthesized. Unexplained amplified DNAs increased when more than 35 cycles of PCR amplification were used. Under standard conditions, approximately 80% of the primers tested amplified DNA, and most revealed 1–5 polymorphisms between BTx 623 and IS 3620C. Primers were used to amplify RAPDs in 32 genotypes of sorghum. In addition, 8 primers detected RAPDs in a population previously used to create an RFLP map for sorghum. These RAPDs were mapped successfully using a population of 50 F₂ plants.