Utilizing Temporal Measurements from UAVs to Assess Root Lodging in Maize and its Impact on Productivity

Abstract

1 2 Both stalk and root lodging can cause significant yield losses in maize; however, maize plants 3 are often able to recover from root lodging. There is potential among breeding programs for 4 developing lines that are more tolerant and can more rapidly recover from root lodging. We 5 assessed the incidence of root lodging utilizing end-of-season lodging scores collected among 6 the Genomes 2 Fields (G2F) initiative trials and found a large yet variable incidence of lodging 7 across states, years, and genotypes. Lodging in this dataset was scored manually at the end of 8 the season, and little is known about the drivers of lodging and lodging recovery. We therefore 9 developed an approach for utilizing temporal plant height measurements collected from 10 unmanned aerial vehicles to capture in-season lodging and recovery in a yield trial consisting of 11 24 maize hybrids planted in replicate under two dates and three planting densities in St Paul, 12 MN in the summers of 2018 and 2019. We found that growth rates during vegetative 13 development as well as the developmental timing of plants when exposed to a storm are 14 predictive of the amount of lodging maize plots will experience. We also found that utilizing 15 temporal height measurements can help in not just estimating lodging and early vegetative 16 growth rates, but that utilizing these estimates can also aid in assessing end of season yield. 17 18 ABBREVIATIONS 19 20 DEM -Digital Elevation Model 21 G2F -Genome 2 Fields 22 PH -Plant Height 23 UAV -Unmanned Aerial Vehicle 24

Maize brace roots provide stalk anchorage

“…In maize, lodging has been shown to reduce yield by 3%-25% (Carter & Hudelson, 1988;Flint-Garcia et al, 2003;Tirado et al, 2020). For stalk lodging, biomechanical measures of stalk breaking strength and stalk flexural stiffness have shown high association with lodging-resistance (Robertson et al, 2016;Sekhon et al, 2020).…”

Bigger is better: Thicker maize brace roots are advantageous for both strength and nitrogen uptake

“…A failure of root anchorage, referred to as root lodging, has detrimental impacts on maize production (Hostetler et al, 2022b; Tirado et al, 2021). We have previously shown that brace root phenotypes (from the roots that enter the soil) can predict the brace root contribution to anchorage and lodging susceptibility (Hostetler et al, 2022b).…”

“…The different origins and destinations of these roots result in different contributions to root functions such as mechanical support, important for lodging resistance, and nutrient supply, required for growth and development. A failure of root anchorage, referred to as root lodging, has detrimental impacts on maize production (Hostetler et al, 2022b;Tirado et al, 2021). We have previously shown that brace root phenotypes (from the roots that enter the soil) can predict the brace root contribution to anchorage and lodging susceptibility (Hostetler et al, 2022b).…”

Multiple brace root phenotypes promote anchorage and limit root lodging in maize

“…Crop failure from mechanical stress is called lodging and is defined as the displacement of plants from vertical (Rajkumara, 2008). In maize, lodging is reported to cause between 7-25% yield loss (Carter and Hudelson, 1988; Flint-Garcia et al, 2003; Tirado et al, 2020) and can be attributed to stalk and/or root failure (Berry et al, 2004; Rajkumara, 2008). Stalk lodging occurs at late growth stages when internodes buckle below the ear, whereas root lodging can occur at any growth stage when the root system fails by uprooting and/or breaking (Berry et al, 2004; Rajkumara, 2008; Erndwein et al, 2020; Hostetler et al, 2021).…”