Abstract Detail

Agronomy

Lee, Shien Yang [1], Robertson, Daniel [2], Julias, Margaret [3], Cook, Douglas [4].

Non-destructive mechanical measurement techniques to predict stalk strength.

Stalk lodging (failure of a plant to remain in an upright position) is a significant cause of yield losses and a critical limitation in the development of high yielding cereal varieties. The propensity of a stalk to undergo lodging is controlled by a wide range of factors including but not limited to weather conditions, fertilizer use, genetics and presence of disease. However, regardless of contributing factors the critical final step in stalk lodging inevitably involves stalk or stem breakage. It was hypothesized that investigating the breakage characteristics of plants could generate novel insights into stalk strength. Such insights could be a vital resource to plant breeders seeking to develop ultra-high yielding crop varieties.
Analysis of the structural failure (i.e. breakage) characteristics of corn stalk conducted in our lab led us to predict that stalk flexural rigidity and cross-sectional area moment of inertia would be better predictors of stalk strength than current measurements methodologies. To test this hypothesis, a series of experiments were conducted on five commercial hybrids of dent corn planted at five different densities across two locations. First high-resolution X-ray computed tomography (CT) was used to obtain three-dimensional models of stalk geometry. Subsequently, stalk strength was measured by subjecting stalks to an artificial lodging scenario which mimicked both the loading conditions and the failure types of naturally lodged plants. Rind penetrometry, a test frequently used to predict stalk strength in existing breeding studies, was carried out to provide a baseline against which to compare novel predictor variables (e.g. flexural rigidity and area moment of inertia). Other quantities commonly used in engineering analyses were also calculated using bending test data and 3D models from CT imaging.
Regression analysis revealed that cross-sectional area moment of inertia and flexural rigidity are better predictors of stalk strength than rind penetrometry. Flexural rigidity and area moment of inertia predicted 83% and 78% of the measured variation in stalk strength respectively. Rind penetrometry, on the other hand, only accounted for 25% of the variation in stalk strength. Both cross-sectional area moment of inertia and flexural rigidity can be measured non-destructively in the field, suggesting promising applications and new approaches to predicting corn stalk strength in future breeding studies aimed at developing lodging-resistant varieties of corn.

1 - New York University - Abu Dhabi, Engineering, Po Box 129188, Abu Dhabi, NA, United Arab Emirates
2 - New York University - Abu Dhabi, Mechanical Engineering, P.O. Box 129188, Abu Dhabi, Abu Dhabi, N/A, NA, UAE
3 - New York University-Abu Dhabi
4 - New York University - Abu Dhabi

Keywords:
biomechanics
Corn
engineering
stalk lodging
Mechanical Stress.

Presentation Type: Oral Paper:Papers for Topics
Session: 37
Location: Salon 2/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 9:15 AM
Number: 37005
Abstract ID:1015
Candidate for Awards:None