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United States Department of Agriculture

Agricultural Research Service

Research Project: Innovative Genetic Approaches for Improving Maize Germplasm for Product Quality and Adaption to Diverse Production Systems

Location: Corn Insects and Crop Genetics Research

Title: Maize canopy architecture and adaptation to high plant density in long term selection programs

Author
item Edwards, Jode
item Alkhalifah, Naser

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary: Increases in grain yield in corn are due largely to the ability of corn to be grown at much higher plant densities. High plant density influences not only the yield of individual plants, but also the size and shape of leaves and plants. In the present study, we found that increased plant density reduces the size of leaves which reduces photosynthetic capacity on a single plant basis. We obtained detailed models of how plant size and leaf size change with increasing density which will improve our understanding of how corn plants need to be changed in order to achieve even higher yields through higher plant densities.

Technical Abstract: Grain yield since the 1930s has increased more than five-fold in large part due to improvements in adaptation to high plant density. Changes to plant architecture that associated with improved light interception have made a major contribution to improved adaptation to high plant density. Improved plant architecture contributes to improved grain yield at high plant density but how plant architecture responds to density and how selection has changed this response is not known in maize. Five populations and two inbred lines were crossed in a diallel mating design and grown at six plant densities. Leaf size and angle were modeled as functions of leaf size and position. We found that the best index of leaf position for predicting size and angle of attachment was a relative node count from the top of the plant. Leaf size decreased consistently with increased density at all leaf positions by about one fourth in the middle of the plant to one third for the flag leaf as density increased for 2 to 10 plants m-2 Leaf angle and plant height followed quadratic density responses with maxima at intermediate densities.

Last Modified: 09/25/2017
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