Molecular Characterization of IITA Maize Inbred Lines Resistant to Striga hermonthica using SNP Markers

Among the major biotic stresses in Sub-Saharan Africa, Striga hermonthica is one of the top biotic stress limiting maize yields. Molecular characterization information on population structure and genetic diversity is important for efficient utilization of germplasm and development of Striga resistant maize varieties. Understanding of the genetic diversity among breeding lines is fundamental in developing cultivars resistant to Striga and other biotic and abiotic stresses. The objectives of this study were to investigate the diversity of 128 Striga resistant maize inbred lines using single nucleotide polymorphism (SNP) DNA markers and to identify their cluster group for effective development of Striga resistant hybrids. The inbred lines were genotyped with 3,297 SNP markers, after filtering the SNP markers based on missing values and their allele frequency. The unweighted pair group method with arithmetic mean (UPGMA) grouped the inbred lines into four distinct clusters consistent with their known pedigrees records. The Strigaresistant inbred lines that were adapted to mid-altitude and low-land tropical agro-ecologies were classified in different clusters. The greatest genetic distance was identified between the clusters of lines L088 and L115/ L073 and L039, suggesting that the genetically distant lines originated from different source population. Our result further identified the genetic grouping present in the source population, which will assist in effective utilization of the lines for exploitation of heterosis in tropical hybrid maize breeding programs.

 

Keywords: Striga hermonthica; genetic diversity; inbred lines; SNP markers