Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Plant Science

First Advisor

Zeno Wicks III


Previous research has produced mixed results on the effect of weed pressure on growth and yield of crop plants. The objectives of this study were (1) to determine the effect of weed stress (yellow foxtail) on the performance of six corn hybrids in 1990 and 1991, (2) to evaluate hybrid yield stability over varying weed and corn plant densities, and (3) to determine if early maturing hybrids compete better with foxtail than later maturing hybrids. Climatological differences played an important role in the outcome of the study. Yield was affected by the interaction of the environment, planting density, weed population, and hybrid differences. As performance increased within environments, the presence of weeds had a more severe effect on hybrid yield as well as plant height and lodging. With decreased yield, plant height, and increased lodging, harvest moisture increased by approximately 0.5-1.00% in the presence of weeds. The presence of weeds caused hybrids to flower later. Since the hybrids in this study were selected due to their positive performance in previous irrigation stress studies, we didn't expect one or more of them to be affected more severely than others. However, this study does show that given a group of hybrids that perform well under moisture stress situations, we are still not able to put these hybrids in a weed stress environment and out perform a weed free environment.

Library of Congress Subject Headings

Hybrid corn -- Effect of stress on
Hybrid corn -- Growth
Hybrid corn -- Yield




South Dakota State University



Rights Statement

In Copyright