Applying mechanical testing strategies to maize brace roots
Date
2021
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Corn (Zea mays L.; Maize) is the top food crop cultivated worldwide and the
United States alone is responsible for about 40% of the global supply. In the wake of
rising global population demands, farmers need to maximize crop yields with limited
land resources. Two environmental stresses that jeopardize maize cultivation and limit
yields are weather and insect herbivory. Wind applies a horizontal force to stalks that
can result in plant uprooting, a phenomenon known as root lodging. To reduce the
negative effects of root lodging, research is needed to investigate the plant features
that may contribute to lodging-resistance. One plant feature that may promote root
lodging-resistance in maize is the presence of brace roots that form at stem nodes
above the soil. Brace roots are proposed to enable maize plants to resist root lodging
and facilitate nutrient absorption, but these functions have not been directly tested. I
hypothesize that brace roots contribute to plant anchorage, the biomechanics of brace
roots enhances this contribution, and that breeding maize for insect herbivory may
influence brace root mechanical performance. My research uses a combination of
mechanical testing methods (field-based bending tests, 3-point bend tests) and imaging
techniques (MicroCT, fluorescence microscopy) to investigate the link between brace
root biomechanics and their contribution to plant anchorage. My results show that: (1)
maize brace roots are important to root anchorage, the extent of which varies with
genotype (2) brace root whorls closest to the soil measure a higher contribution to root
anchorage and higher structural mechanical properties, (3) brace root biomechanics
may be a factor in increasing their contribution to plant anchorage, and (4) breeding
maize for insect resistance traits may compromise plant anchorage. The results of my
research provide a foundation for targeting brace roots to promote lodging resistance
in maize and other cereal crops
Description
Keywords
Anchorage, Bending, Lodging, Phenotyping, Root, Stalk