Molecular Characterization of Quality Protein and Normal Maize Accessions from a Breeding Program: Identification of Variety-Diagnostic Markers.

Quality protein maize (QPM) offers potential to increase maize nutritional value and combat issues of malnutrition in developing countries. A new  maize variety, named MUDISHI 3 has been developed in the DR-Congo breeding program. The objective of this study was to determine the amino acid profile of this variety and to develop variety-diagnostic markers. Protein analysis data revealed that MUDISHI 3 is a QPM variety that is distinct from its original population (DMR-ES-W). Lysine content in MUDISHI 3 was 3.6 g of lysine / 100 g which represents a significant increase of 25%, over the original population (DMR-ES-W) and the genetically improved normal maize variety (Salongo 2) that is currently released. Genomic DNA was extracted from fifteen different maize varieties. They were quantified and amplified through polymerase chain reaction (PCR) using inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) primers. One ISSR diagnostic-marker of 480 bp that was identified was unique to the QPM variety MUDISHI 3. This diagnostic marker was cloned in pGEM-T EASY vector and sequenced. Primer pair targeting this sequence was synthesized to develop sequence characterized amplified region (SCAR) marker. This SCAR marker was present in all the QPM and normal maize accessions. The development of this  ISSR diagnostic marker  in the present study indicate that it is possible to develop a molecular breeding program of QPM varieties in a maize improvement program.