Physiological and agronomic responses of maize (Zea maysL) cultivars to plant population and defoliation at post-anthesis in the humid rainforest

Variations in response pattern of maize (Zea mays)grown at plant populations, defoliated at post-anthesis in the rainforest were tested. Two field trials were conducted at Abeokuta, (Longitude 3025’E, Latitude 7015’N; 144 m a.s.l) and Ibadan (3056’E, 7033’N: 168 m a.s.l), Nigeria in 2015. The trials consisted of maize variety {2009 TZE-W DT STR [open pollinated variety (OPV)] and TZEI 124 × TZEI 25 (hybrid)]} in the main plot, plant population (71111, 80000 and 106666 plant ha-1) in sub plot and defoliation (+ defoliation and – defoliation) as sub-sub plot. It was laid out in a split-split plot arrangement fitted into randomised complete block design with three replicates. OPV had significantly higher assimilatory surface, rate of current photosynthesis, reduced dry matter translocation efficiency, reduced days to 50 % anthesis and more 1000 grain massthan the hybrid maize, with similar grain yields. Both locations experienced increased leaf area index with increased plant population. Reduced 1000 grain massat both locations when maize was defoliated suggested a disruption in source:sink balance