Maize Streak Virus (MSV) disease is a major threat to cereal crops amongst smallholder farmers in sub-Saharan Africa. The purpose of this research was therefore, to identify lines with resistance to MSV using phenotypic and genotypic markers. To achieve this, early generation maize S1 lines were grown for phenotypic evaluation in the IITA greenhouse at Ibadan, Nigeria. Symptom severity was assessed visually using a 1–5 rating scale. Leaf tissues from infected maize were harvested and grinded for ELISA

test. Besides, leaf tissues from healthy maize were harvested, dried for DNA extraction and shipped to the laboratory for SNP genotyping. The data on severity scores and recovery response was analysed using One-way ANOVA in SAS Software. The means were separated suing Tukey’s post Hoc test and p<0.05 was considered statistically significant. The symptom severity scores differed significantly between the maize pedigree (p = 0.0001). The severity scores ranged from 4-5 within the first week of MSV inoculation with a mean incidence of 80%. Symptoms were recorded 3-5 days after the inoculations. Symptoms severity was significantly high on leaves found on the upper part compared to the leaves located on the lower plant parts. However, after two weeks, the symptoms severity declined with the lowest severity reported six (6) weeks after the inoculations. Twenty three maize lines had recovery response of >50% while 56 lines recorded response ranging 30 – 77.4% hence considered resistant. In contrast, 38 maize lines had a recovery response of < 30% and were considered susceptible. The highest AFV values were recorded in maize lines 35 (3.68), 49 (2.38), and 37 while the lowest values were recorded in maize lines 90, 44, and 75 respectively. Based on the four selected SNP markers, 56 maize lines were resistant to MSV, 16 lines were moderately resistant while 22 were susceptible. The maize lines which were resistant to MSV virus to be further screened for future use in breeding programs and subsequent distribution to farmers for production.

Highlights

• MSV virus is endemic to SSA causing significant economic impacts on increased maize yield loss, low income and increased prices of maize grain.
• Profiling the MSV resistant maize genotypes for utilization in breeding programs and subsequent distribution to farmers for production.
• Severity of infection was highest the first two weeks but reduced thereafter over time indicating their ability to resist the virus.