Development of Quality Protein Maize (QPM) Inbred Lines and Genetic Diversity Assessed with ISSR Markers in a Maize Breeding Program

Very few studies have been conducted to develop new quality protein maize (QPM) varieties adapted to various agro-ecological conditions in Africa. Such QPM varieties with high grain yield, genes for resistance to local disease and pests would contribute to increased grain production and to alleviate poverty and malnutrition. During the first step of the QPM breeding program in the DR-Congo, 137 inbred lines were developed and selected in the field based on various agro-morphometric characteristics. Molecular analysis revealed high level of genetic variability among inbreds. The level of polymorphic loci observed with ISSR markers varied between 74% and 80%. Nei’s gene diversity and Shannon’s information index values varied from 0.22 to 0.27 and from 0.34 to 0.41, respectively. The majority of inbred lines were distantly related. In fact, more than 87% of genetic distance values were above 0.50. The genetic distance values among the different parental maize accessions varied from 0.39 to 0.72. Inbred lines from the same parental accession were also not genetically close with genetic distance values varying from 0.28 to 0.59. More importantly, the ISSR data are useful in the selection of inbred lines to be tested for general and specific combining abilities and further development of synthetics