Maize Stalk Lodging: Flexural Stiffness Predicts Strength

Abstract

Late‐season stalk lodging in maize (Zea mays L.) is a major agronomic problem that has far‐reaching economic ramifications. More rapid advances in lodging resistance could be achieved through development of selective breeding tools that are not confounded by environmental factors. It was hypothesized that measurements of stalk flexural stiffness (a mechanical measurement inspired by engineering beam theory) would be a stronger predictor of stalk strength than current technologies. Stalk flexural stiffness, rind penetration resistance and stalk bending strength measurements were acquired for five commercial varieties of dent corn grown at five planting densities and two locations. Correlation analyses revealed that stalk flexural stiffness predicted 81% of the variation in stalk strength, whereas rind penetration resistance only accounted for 18% of the variation in stalk strength. Strength predictions based on measurements of stalk flexural stiffness were not confounded by hybrid type, planting density, or planting location. Strength predictions based on rind penetration resistance were moderately to severely confounded by such factors. Results indicate that stalk flexural stiffness is a good predictor of stalk strength and that it may outperform rind penetration resistance as a selective breeding tool to improve lodging resistance of future varieties of maize.

Stalk Lodging: A Portable Device for Phenotyping Stalk Bending Strength of Maize and Sorghum

“…Second, data from DARLING was analyzed to check that it was in agreement with laboratory based protocols for testing maize stalks in bending. In particular, laboratory experiments have demonstrated that stalk flexural stiffness is strongly correlated with stalk bending strength (Robertson et al, 2016). This same correlation is observed in the data collected using DARLING (see Figure 7).…”

The genetic architecture of biomechanical traits in sorghum

“…The mechanical stability of plants depends on the material properties of tissues and the geometry, shape, and size of plant organs, as well as the genetics, environment, and loading forces applied to plants (Berry & Berry, 2015; Niklas, 1992; Paolillo & Niklas, 1996). Therefore, breeding for superior stem mechanical traits can enhance resistance to wind‐induced lodging in a variety of crops (Berry & Berry, 2015; Li et al., 2009; Robertson, Lee, Julias, & Cook, 2016; Sposaro, Berry, Sterling, Hall, & Chimenti, 2010). Although the mechanical properties of stems from different crops have been reported, only a few of these studies have included genetic analysis of stem mechanical traits.…”

Stalk Bending Strength is Strongly Associated with Maize Stalk Lodging Incidence Across Multiple Environments

“…Root lodging can cause a varying degree of yield losses (Bian et al, 2016). Stalk lodging, which involves breakage of a stalk below the ear, is usually observed as plants approach physiological maturity (Robertson et al, 2016) and often leads to total loss of the grain (Albrecht et al, 1986). Improving stalk lodging resistance (see Box 1 for description) offers an opportunity to substantially increase maize production without increasing agricultural inputs including irrigation, fertilizer, and crop management expenses.…”

“…Assessment of stalk lodging resistance has traditionally relied on late-season stalk lodging incidence counts obtained by recording the number of lodged plants in a defined area. Currently, lodging counts are the most widely used method for determining lodging resistance in breeding programs (Robertson et al, 2016). However, this method is confounded by numerous factors including varying levels of disease, pest pressure, soil fertility, wind velocity, and other weather and environmental conditions at the locations used for evaluation (Thompson, 1972;Hondroyianni et al, 2000;Flint-Garcia et al, 2003a;Hu et al, 2012;Robertson et al, 2016).…”