Genetic Variability and Classification of Highland Adapted Quality Protein Maize Inbred Lines Using SSR Markers

Abstract

Development of improved quality protein maize (QPM) varieties/hybrids would complement strategies for reducing problems of malnutrition in  developing countries such as Ethiopia.The highland maize breeding program in Ethiopia, in collaboration with CIMMYT, has developed QPM inbred lines  adapted to highland sub-humid maize agroecology. However, there is limited information on the genetic variability and interrelationship among the QPM  inbred lines. The present study was, therefore, conducted to assess the genetic variability and thereby classify elite QPM inbred lines developed for  tropical-highlands and highland transition maize agro-ecologies using microsatellite (SSR) markers. A total of 36 white-grained maize inbred lines,  including 30 QPM and six non-QPM were genotyped using 26 simple sequence repeat (SSR) markers. Estimates of the average number of alleles per  locus, gene diversity, and polymorphism information content (PIC) were 3.8, 0.53, and 0.49, respectively. Pairwise Euclidean genetic distances ranged  from 0.11 to 1.10 with mean of 0.74.Three major genetic groups were also identified, which are generally consistent with available pedigree information  except a few discrepancies. Therefore, the genetic classification using the SSR markers could assist in strategic QPM breeding for tropical-highland and  highland transition agro-ecologies. The outputs also form the basis for future studies aimed at confirming heterotic groups and identifying any new  heterotic patterns that can emerge in the highland QPM germplasm.