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Thesis (M.S.)—University of Nebraska—Lincoln, 1968. Department of Agronomy.


Copyright 1968, the author. Used by permission.


Many studies have related the structure, development, and reproduction of the corn (Zea mays L.) plant to its environment.Morphological characteristics of the corn plant influence its reaction to environmental conditions.In turn, the environment determines to an extent how the corn plant must adjust to compete successfully with other organisms in its habitat.

Man has modified the corn plant and its ecological community.Additions of fertilizers, insecticides, herbicides and irrigation water have been coupled with alterations of planting pattern, planting date, row spacing and plant population.The advent of hybrid corn provided not only a block with which to build, but one that can be changed to meet the building design.

Present corn yields should be examined and yield goals pushed upward.Known technology must be accepted—and improved—if progress toward higher yields is to continue.Farmers, agri-businessmen and scientists need to learn more about corn plant growth.Initiation of cultural practices depends on stage of plant development.Logic dictates that for production practices to be successful they be properly applied and timed.

At present, stage of corn growth is often determined by counting the number of leaves on the plant.Lower leaves are lost through normal plant development and tillage practices.There is considerable evidence that indicates a differing relative importance of lower versus upper leaves.By counting total actual leaves instead of only those currently visible, stage of growth can be more accurately determined.

Experimental work reported herein was conducted over a two-year period to determine if lower internode elongation could be utilized to identify actual leaf stages.Hybrid and variety, date of planting and population variables were introduced to determine if the first lower internode to elongate was similar under widely variable conditions.A series of photographs depicting differing stages of growth were developed throughout the period of experimentation.

Advisor: W. L. Colville