CANOPY ARCHITECTURE AND GRAIN YIELD OF MAIZE (ZEA MAYS L.) IN THE RAINFOREST OF SOUTHWESTERN NIGERIA

Plant architecture is a key factor for optimum productivity in most crops. Unfortunately, this aspect of maize (Zea mays L.) crop configuration has recieved little attention from researchers in the rainforest ecologies of Nigeria.We investigated the effects of the environment on canopy architecture and, in turn, canopy orientation on grain yield of maize in the rainforest of sw Nigeria. Five maize varieties were planted weekly from March to November of 2016 and 2017 in randomized complete block experiments at the Obafemi Awolowo University Teaching & Research Farm (OAU T&RF). Data were collected on canopy architecture, which was quantified with upper and lower leaf angle (LAUpper and LALower) and leaf orientation values (LOVUpper and LOVLower) obtained at the grain-filling stage.-At maturity, grain yield, along with some of its components (ear length, ear diameter and kernel row number) were also obtained from all plots. The data were subjectedto ANOVA, correlation, regression, and sequential path analyses to determine the relationship of grain yield with canopy architecture. The environment and genotype had significant effects on canopy architecture, grain yield (P = 0.01; R2 ≥ 80 %), and yield components. Leaf orientation value of the upper canopy (LOVUpper), with correlation coefficient r = 0.61** and direct positive causal effect (P = 0.61), rather than LAUpper, LALower and LOVLower, greatly affected grain yield. In conclusion, LOVUpper was the single most important leaf architecture index that positively affected grain yield which, in turn, was influenced greatly by the environment in the rainforest ecology of SW Nigeria