Farm Progress

With help of Spidercam and sensor technology, researchers improve phenotyping throughput and efficiency of plant breeding.

Tyler Harris, Editor

August 2, 2017

4 Min Read
HEAVY LIFTING: While the combined weight of the dolly and sensor is about 220 pounds, researcher Frank Bai notes the maximum capacity of the eight cables supporting it is much greater. "If you had an F-150 pickup, two of the cables could hold the truck,” says Bai.

Although you may not know it, you've probably seen a Spidercam in action. The cameras, designed by an Austrian company of the same name, have been used to cover college and professional sporting events as well as concerts.

However, you probably haven't seen this technology used to watch plants grow — unless you've been to the University of Nebraska-Lincoln's Field Phenotyping Center.

This spring the center installed the Spidercam on its 1 acre of land at ENREC. Later this summer, Geng "Frank" Bai, postdoctoral research associate, discussed the new technology at an ENREC Open House.

"This is, to our knowledge, the only facility in the U.S. using this technology for field phenotyping of plants," says Bai.

High-throughput phenotyping
How does it work? Picture four poles on the corner of a 1-acre field. At each pole is a winch house, and adjacent to the field is a control station. The cables in the winch houses connect to a dolly that is hanging in the air over the 1-acre field and is controlled from the control station.

The dolly is equipped with several kinds of sensors:

• A VNIR (visible and near infrared) sensor can be used to measure plant vegetation cover and NDVI (normalized difference vegetation index).

• A thermal infrared camera can help measure crop canopy temperature and relate it to plant transpiration and water stress.

• A LIDAR (light detection and ranging) sensor measures canopy structure and height, allowing users to get a three-dimensional measurement of the plant

• A spectrometer measures spectral reflectance in the canopy, allowing the operator to measure different vegetation indices.

Because the Spidercam is so close to the canopy, it can also collect images at much higher resolution than other airborne phenotyping methods, Bai adds. Meanwhile, because it moves along the X, Y and Z axis, it can be positioned accurately to the point researchers want to measure.

This is part of a high-throughput phenotyping system, which Bai says will help make researchers more efficient in working with plant breeders and geneticists to identify and select for desirable traits. Phenotyping involves collecting data on various physical features of plants — stress, height, biomass, flowering date, etc.

LEAF-LEVEL IMAGERY: Frank Bai discusses the Spidercam at an ENREC Open House earlier this year. Because the Spidercam is so close to the canopy, it can collect images at higher resolution than other airborne phenotyping methods, Bai says.

"Right now, conventional phenotyping is almost always done manually. For example, we have to enter a field and use a yardstick to measure the height of corn or soybeans. It could be quite subjective. It's not very accurate. It's very labor-intensive," Bai says. "Genotyping is now already very efficient and low cost. The bottleneck of plant breeding and genetics research is mainly on the phenotyping side. If we can do high-throughput field phenotyping, we can break that bottleneck and substantially increase  the overall efficiency of gene discovery and crop improvement."

Putting data to use in genetics
Yufeng Ge, Bai's adviser and assistant professor of Biological Systems Engineering at UNL, notes with this phenotypic data, breeders and geneticists can be directed to target specific measurements and select lines with desirable traits like higher yield and more efficient water use.

"You can measure a lot of traits from this system. Those traits can be a direct measurement or secondary traits — not a direct measurement but derived from it. One good example is that you can use this system to make multiple measurements across the season to get biomass accumulation rate," says Ge. "This is really important for yield, and knowing biomass accumulation is challenging with conventional phenotyping."

Monitoring water use
But the Spidercam isn't the only piece of the puzzle. The site is also equipped with technology to help monitor water use, which Ge notes is one of the biggest traits of interest at the center.

Twelve inches beneath the entire field is a subsurface drip irrigation system with emitters that can control water applications for each plot. Installed by Suat Irmak, a Harold W. Eberhard Distinguished Professor at UNL's the Department of Biological Systems Engineering, the SDI system allows researchers to control how much water is applied to irrigate each individual plot with a high level of precision.

Irmak also installed a Bowen Ratio Energy Balance System to measure evapotranspiration (ET), other surface water and energy fluxes, and numerous other variables. The center is also equipped with soil moisture sensors to measure the available water in the soil profile continuously.

"We have a controlled irrigation facility. It's divided into many small plots, and you can deliver water in a precise way to those individual plots. We have instruments to measure from different angles regarding how much water has been used by the plants from each plot," Ge says. "From different angles, hopefully, we can paint a more complete picture of what water use looks like, and how that is meshed with genetics, environment and management. With the national interest in agricultural water use and water use efficiency, the field phenotyping center at UNL positions researchers well to be innovative and competitive in addressing these critical challenge areas of agriculture."



About the Author(s)

Tyler Harris

Editor, Wallaces Farmer

Tyler Harris is the editor for Wallaces Farmer. He started at Farm Progress as a field editor, covering Missouri, Kansas and Iowa. Before joining Farm Progress, Tyler got his feet wet covering agriculture and rural issues while attending the University of Iowa, taking any chance he could to get outside the city limits and get on to the farm. This included working for Kalona News, south of Iowa City in the town of Kalona, followed by an internship at Wallaces Farmer in Des Moines after graduation.

Coming from a farm family in southwest Iowa, Tyler is largely interested in how issues impact people at the producer level. True to the reason he started reporting, he loves getting out of town and meeting with producers on the farm, which also gives him a firsthand look at how agriculture and urban interact.

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