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Submitted to: Crop Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/11/2016 Publication Date: 5/27/2016 Citation: Edwards, J.W. 2016. Genotype by environment interaction for plant density response in maize. Crop Science. 56:1493-1505. doi:10.2135/cropsci2015.07.0408. Interpretive Summary: Maize yields are highly dependent on plant density. Little public information is available on variation in optimal densities among production environments. This research was conducted to determine how much optimum plant densities vary among environments and how much optimum planting densities for a maize variety depend on the specific production environment. For a set of maize varieties representing a wide range of advancement, optimal plant densities varied from 5.6 plants per square meter to 9.1 plants per square meter. The optimum planting density for any given variety depended on the specific combination of environment and variety. The research demonstrates that optimal densities are highly variable among environments presenting an opportunity and a challenge for producers and researchers to determine the best planting density for each production environment. This information will benefit all in maize research and production. Technical Abstract: Increased adaptation to high plant density has been an important factor in improvements in grain yield in maize. Despite extensive public literature on variation in plant density response among maize varieties, almost no public information is available on environmental effects on plant density response or on genotype by density interaction for plant density response for grain yield in maize. The present study was conducted to quantify environment effects and genotype by environment interaction effects on plant density response for maize grain yield. A set of 57 synthetic populations, synthetic by inbred line crosses, and synthetic by synthetic population crosses were evaluated across a five year period including 17 individual locations a year. The data in this study were an unbalanced combination of multiple experiments that included 370 pedigree-environment combinations with each containing at least four planting densities and two replications per environment in most cases. Genotype by environment interactions accounted for 27 percent of total genetic variance (genetic plus genotype by environment interaction) in linear regression coefficients and 39% of variance in quadratic regression coefficients in the regression of grain yield on plant density. Variance in genotype by environment interactions for linear and quadratic regression coefficients resulted in variation in optimal densities among varieties being highly specific to individual environments. In addition, average plant density responses varied widely among environments with average optimal plant densities ranging from 5.6 plants m-2 to 9.1 plants m-2. |
