Genetic relationships and heterotic structure of quality protein maize (Zea mays L.) inbred lines adapted to eastern and southern Africa

Information on heterotic patterns of quality protein maize (QPM) inbred lines would help to design appropriate breeding strategies for QPM. The objectives of this study were to assess the genetic relationships and heterotic structure of elite QPM inbred lines adapted to eastern and southern Africa (ESA) using simple sequence repeat (SSR) markers. Thirty-five inbred lines consisting of 32 QPM and three non-QPM inbred lines were genotyped using 40 SSR markers that yielded a total of 217 alleles, with an average of 5.43 and range of 2-10 alleles per marker. The number of alleles per inbred line varied from 40 to 82, with a mean of 51.5. About 81% of the pairwise comparisons between the lines had genetic distance estimates varying from 0.250 to 0.415. The unweighted paired group method using arithmetic averages (UPGMA) clustering algorithm and model-based population structure analysis showed the presence of two to three major groups, mainly consistent with maturity groups and pedigree information. This information can facilitate effective utilization of the QPM inbred lines in breeding programs.