MITOCHONDRIAL AND TOTAL DNA RAPD PATTERNS CAN DISTINGUISH RESTORERS OF CMS LINES IN SORGHUM

Seven sorghum restorer lines that differentially restore (or maintain) the Al and A2 cytoplasmic male-sterile (CMS) cytoplasms were studied by RFLP analyses of their mtDNAs and RAPD analyses of their mitochondr ial DNA (mtDNA) and total DNA to understand nuclear mitochondrial comb inations that are present in these lines. RFLP data from II mitochondr ial gene probes were inadequate to classify these seven lines. However , the analysis of RAPD profiles of total DNA could distinguish these l ines on the basis of their ability to restore completely or partially the fertility in the A1/A2 CMS cytoplasms. Interestingly, RAPD profile s of mtDNAs of these lines also followed the same pattern as that of t he total DNA. These results indicate that the different restorer lines possess specific nuclear-cytoplasm combinations. Further, the results also show that the RAPD technique can be used to identify markers for different cytoplasms used in CMS.