Maize (Zea mays L.) production in Sub-Saharan Africa has been declining due to Striga infestation. This study evaluated the response of 176 inbred maize lines to Striga infestation, refined heterotic grouping, and their genetic diversity at IITA, Ibadan, Nigeria. Each line was replicated three times in a rhizotron in a completely randomized design. Pre-germinated Striga seeds were spread on maize roots. Height, number of leaves, and internodes were recorded per maize plant. Striga damage was scored using a scale; the number of Striga plants attached to maize roots was counted, and the striga biomass was recorded.Leaf tissues of maize were sampled for DNA extraction. STRUCTURE software and harvester were used to assess population structure; TASSEL software for principal component analysis, and means were separated using Tukey’s HSD. GenAIEx software and Powe  Maker were used for genetic diversity and heterozygosity. TZISTR2004 attained the highest plant height (94.77cm) while TZISTR1873 recorded the lowest (38.33cm). TZISTR2042 recorded the highest number of leaves, while TZISTR2247 had the lowest(11.33cm). Internodes were highest (15.67) in TZISTR2042, while lowest (10.33) was on TZISTR2275 and TZISTR2247. Plant scorching was highest (9.00) in TZISTR2100, TZISTR2269, TZISTR2287, whereas TZISTR1318 recorded 1.00. TZISTR1126 had 18.72 striga attached while TZISTR2175, TZISTR2241, TZISTR2102, TZISTR2270, TZISTR2287 had none. Striga biomass was highest (22.72g) on TZISTR2129, and TZISTR2175 attained the least weight. Heterozygosity ranged between 0.0 to 0.85. Major allele frequency ranged between 0.5-1.0, whereas gene diversity ranged from 0 to 1.0. The identified lines with resistance to Striga could be utilized in maize breeding programmes to enhance production in Sub-Saharan Africa.

Highlights

• Striga infestation significantly reduced the plant height, internode length, and number of leaves of the inbred maize lines, which have low or no resistance to the parasite.
• The inbred lines have the potential to contribute new alleles, which can be utilized in future breeding programs for resistance to striga.
• The number of Striga attached to the roots and biomass was lowest in resistant lines, attributed to reduced production of the Striga germination stimulants and a reduction in nutrients from the host.
• SNP markers assigned the inbred maize lines into heterotic groups based on their genetic makeup, background, and the source population, aligning lines from the same pedigree in one subpopulation.