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Molecular markers are fast, efficient and reliable in detecting distinct differences between genotypes at DNA level. In particular, polymerase chain reaction (PCR)-based markers are widely preferred for genotype characterization in diverse crop species, including maize. It is impossible, however, to obtain the entire information required in plant breeding and conservation programmes solely from a single marker system without integration with other technique(s). The current study was, therefore, initiated to compare results from random amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR) markers in combination with high resolution melt analysis for effectiveness in detecting genetic variability or similarity among selected QPM inbred lines. Eight fresh leaf samples (two per line) were collected from each line for DNA extraction. The genomic DNA extracts were subjected to polymerase chain reaction (PCR) and high resolution melt analyses which involved three RAPD primers and three SSR primer pairs using a Real-Time PCR System. The curves of the HRM analysis showed fairly similar melt patterns among the lines for both types of marker systems. Results obtained from the gel-electrophoresis and genetic distance measures for RAPD markers were also in agreement with the HRM analysis. In general, both marker systems in combination with HRM analyses were able to detect genetic variations within and between the inbred lines, thus justifying the potential use of HRM analysis and indicating the possibility of excluding the use of gel-electrophoresis at the early stage of screening of large number of samples of newly developed inbred lines in order to save time and resources. Key words: Genetic variability, polymerase chain reaction, quality protein maize, random amplified polymorphic DNA, simple sequence repeats.

Pyruvate formate-lyase (PFL) catalyses the non-oxidative dissimilation of pyruvate to formate and acetyl-CoA using a radical-chemical mechanism. The enzyme is enzymically interconverted between inactive and active forms, the active form contains an organic free radical located on a glycyl residue in the C-terminal portion of the polypeptide chain. Introduction of the radical into PFL only occurs anaerobically, and the activating enzyme responsible is an iron-sulphur protein that uses S-adenosyl methionine as cofactor and reduced flavodoxin as reductant. As the radical form of PFL is inactivated by molecular oxygen it is safeguarded during the transition to aerobiosis by conversion back to the radical-free, oxygen-stable form. This reaction is catalysed by the anaerobically induced multimeric enzyme alcohol dehydrogenase. The genes encoding PFL and its activating enzyme are adjacent on the chromosome but form discrete transcriptional units. This genetic organization is highly conserved in many, but not all, organisms that have PFL. Recent studies have shown that proteins exhibiting significant similarity to PFL and its activating enzyme are relatively widespread in facultative and obligate anaerobic eubacteria, as well as archaea. The physiological function of many of these PFL-like enzymes remains to be established. It is becoming increasingly apparent that glycyl radical enzymes are more prevalent than previously surmised. They represent a class of enzymes with unusual biochemistry and probably predate the appearance of molecular oxygen.