Performance and Profitability of Released Climate-Smart Maize Varieties Under Increased Plant Densities

The study was conducted to; validate the genotypic performance of the popular climate-smart released maize varieties under increased plant densities in the three sub-ecologies (Mid-altitude, semi-arid, and tropical rain forest zones), which are important maize crop production belts and testing sites for new hybrids, and estimate the profitability of growing the varieties under optimum plant density in the different sub-ecologies. Seven popular varieties; MM3, Longe 6H, Longe 9H, Longe 10H, Bazooka, WE 3106, and FH5160 were tested for two seasons at four different spacing levels- 0.75 × 0.6 M (44,444 plants ha-1), 0.75 × 0.30 M (44,444 plants ha-1), 0.75 × 0.25 M (53,333 plants ha-1), and 0.5 × 0.3 M (66,667 plants ha-1). The varieties varied significantly for grain yield (GY) and ear aspect (EA) traits across the spacings and environments. Using the closest spacing (0.50 × 0.30 M) resulted in higher GY productivity and net profit in the testing sites. At optimal spacing, FH5160 was the most stable genotype for cultivation across the three sub-ecologies. All varieties exhibited superior genotypic performance for GY (7-12 t ha-1) and EA traits in the mid-altitude zone. Bazooka and Longe 10H were the best varieties for the tropical rainforest zone. While MM3, WE3106 and Bazooka were more suitable for semi-arid zone. Growing all the studied maize varieties in the mid-altitude sub-ecological zone is profitable, especially at optimal spacing.