Path Analysis Comparison of Plant Population and Hybrid Maturity for Maize Primary and Secondary Yield Components

Limited yield component analysis of maize (Zea mays L.) using path correlation analysis exists related to crop management in Europe and the United States. The objective of this study was to compare the results generated from path correlation analysis of primary to those of the primary plus secondary yield components and relate these to maize breeding and production research needs. Research was conducted in 2012 and 2013 at Zagreb, Croatia and Mead, Nebraska, United States with maize hybrids ranging from 520 to 650 FAO maturities, and plant populations ranging from 65,000 to 105,000 plants ha-1. Grain yield, ears m-2, rows ear-1, kernels ear-1, kernels row-1, and kernel weight were determined. The path coefficient analysis of primary yield components of ears m-2, kernels ear-1, and kernel weight confirmed that yield component compensation occurred partially accounting for similar yields over a broad range of plant populations and due to hybrid maturity, with all primary grain yield components having direct effect on grain yield. The primary plus secondary indicated the important role of the number of rows ear-1 for maize grain yield for high plant population and early-maturity maize hybrids, and the number of kernels row-1 and kernels ear-1 importance at low plant populations and for mid- and late-maturity maize hybrids. When only primary yield components are included in the analysis, the importance of the secondary grain yield components of rows ear-1 and kernels row-1 on later occurring yield components and on yield was unavailable. Future yield component studies should use path analysis and include both primary and secondary grain yield components to better understand production and genetic factors leading to yield similarities and differences