Strong winds and rain can cause maize stalks to break, making harvest more difficult and reducing harvestable yield. Global yields of cereal crops are currently reduced by 5% annually due to stalk lodging. Climate change is expected to generate greater frequency of wind events, which will increase the likelihood of lodging.
The first step towards enhancing lodging resistance through breeding and/or biotechnology is to unravel the role of individual stalk morphological features controlling stalk bending strength, which is a crucial factor in determining lodging resistance.
A new study published in in silico Plants presents a new method to identify how individual morphological features of maize stalks control their stiffness and strength. Graduate student Michael Ottesen and colleagues in the Mechanical Engineering Department at Brigham Young University created a three-dimensional model of the maize stalk, including its geometry and material properties, to assess flexural stiffness and ultimate strength.
The authors used three-point bending tests and CT scans that were previously conducted for 900 maize stalks to parameterize the model.
During bending tests, stalks were gradually loaded until buckling occurred. This testing approach provided empirical measurement of two mechanical features of each stalk: flexural stiffness and bending strength.
Stalk cross-section parameters were extracted from the CT data. This allowed the authors to incorporate the different mechanical features of the pith and rind into the model.
A combination of machine learning and feature identification were used to create 51 unique parameters that best correlated with flexural stiffness and ultimate strength.
The authors tested the model by comparing the flexural stiffness and strength of simulated stems with actual stems having the same parameters. The new model accurately captured the behavior and trends observed in empirical tests of maize stalks.
Finer control of stalk morphology values will allow users to more precisely determine which morphological changes could provide the greatest increase in strength for the smallest overall change in morphology and overall stalk mass.
This new model can be used to identify which morphological changes could provide the greatest increase in strength for the smallest overall change in morphology and overall stalk mass. Moreover, because all grains rely upon a similar geometric architecture this model can be parameterized to apply to other grain species such as sorghum, wheat, oats, and rice.
READ THE ARTICLE:
Michael Ottesen, Joseph Carter, Ryan Hall, Nan-Wei Liu, Douglas D Cook, Development and stochastic validation of a parameterized model of maize stalk flexure and buckling, in silico Plants, Volume 5, Issue 2, 2023, diad010, https://doi.org/10.1093/insilicoplants/diad010