The optimum plant density for the offseason hybrid maize production in the hot‐submoist tropical environment of southwestern Ethiopia can differ from the rainy‐season

Abstract Agronomic practices for good crop performance vary with variety and growing conditions. A split‐plot experiment was conducted in the dry season in southwestern Ethiopia to determine growth, yield component, and yield responses of medium‐ and late‐maturing hybrid maize ( Zea mays L.) varieties (BH‐546 and BH‐661, respectively) to different plant densities (39,216, 44,444, 47,059, 51,282, 53,333, 58,824, 61,538, 66,667, and 76,923 plants ha −1 ) and to optimize the plant density for offseason hybrid maize production in the hot‐submoist tropical environment of the study area. Both variety and plant density significantly affected most growth traits and yield components considered, while their interaction significantly affected grain yield and harvest index. The late‐maturing variety provided higher growth and yield components than the medium‐maturing variety. The higher plant density (66,667 and 76,923 plants ha −1 ) showed a higher leaf area index and biomass yield followed by 53,333 plants ha −1 . However, the higher plant density (76,923 plants ha −1 ) produced a smaller stalk diameter, leaf area, cobs, and 1000‐grain weight than the other plant densities. The late‐maturing variety planted at 66,667 plants ha −1 and the medium‐maturing variety planted at 53,333 plants ha −1 produced a higher grain yield with a higher economic return than the other variety–plant density combinations, suggesting that these plant densities can be used for hybrid maize production under irrigation system in the offseason in the study area. This study also pinpointed that the optimum plant density for offseason maize production differs from that is recommended for the rainy season (44,444 plants ha −1 ).