Variety-Specific Responses of Maize to Mycorrhizal Inoculation in Low-Fertility Tropical Soils

Maize (Zea mays L.) productivity in tropical soils is often limited by acidity, low fertility, and nutrient deficiency. This study evaluated the effects of arbuscular mycorrhizal fungi (AMF) inoculation on the vegetative growth of three maize varieties namely: Sammaz-52, Oba-98, and Oba Super-2, which were cultivated in acidic sandy loam soils at the University of Port Harcourt, Nigeria. We used a completely randomized design with three AMF levels (0%, 5%, and 10%) and three replicates per treatment. Soils were sandy (sand 817–832 gkg⁻¹), moderately acidic (pH 4.70–5.30), with low to moderate organic carbon (4.78–13.56 gkg⁻¹), total nitrogen (0.98–1.75 gkg⁻¹), and available phosphorus (19.40–41.80 mgkg⁻¹). AMF inoculation significantly enhanced plant height, leaf area, and stem girth across the different cultivars. At 12 weeks after planting, the tallest plants were recorded in Oba Super 2 with 10 % AMF (382.33 cm² leaf area; 88–103 cm height), while Oba-98 and Sammaz-52 attained 84.0 and 91.7 cm, respectively, under the same treatment. The highest leaf area was observed in Oba Super-2 at 382.33 cm² (10% AMF), followed by Oba-98 (336.67 cm²) and Sammaz-52 (338.33 cm²). Stem girth responses were variety- and dose-dependent: Oba-98 performed best at 5 % AMF (5.33 cm), Oba Super-2 at 10 % AMF (5.13 cm), and Sammaz-52 showed limited response to higher inoculation (4.73–4.90 cm). Enhanced growth was attributed to improved nutrient uptake, particularly phosphorus and nitrogen, facilitated by mycorrhizal colonization, mitigating the constraints of acidic, low-fertility soils. The results highlight that varietal selection and optimized AMF application can significantly improve vegetative development, offering a sustainable strategy for maize production under tropical soil conditions