Technology Center Phenotyping: How sugar beets can withstand climate change

Can you tell how well a plant copes with drought stress just by its external appearance? Yes! At the Technology Center Phenotyping of Fraunhofer IIS in Merkendorf, researchers from the Development Center for X-ray Technology combine innovative camera systems with X-ray technology. This helps the seed producer Strube make its sugar beets fit for the challenges of climate change.

Sugar beets are among the most important agricultural crops in Europe, accounting for around 20 percent of global sugar production. Like many other plants, they are under increasing pressure: rising temperatures, pests, and diseases are taking their toll. In particular, drought stress caused by a lack of rainfall poses a major challenge for this crop. “Climate change has long been a reality in agriculture,” says Dr. Fabian Keil, Group Manager for Optical Phenotyping at the Development Center for X-ray Technology at Fraunhofer IIS. He is researching the extent to which a plant’s external appearance can provide insights into how well it copes with different environmental conditions.

»In plant breeding, phenotyping is crucial for identifying traits that should be passed on to the next generation.«

Dr. Fabian Keil

Keil and his team use what is known as phenotyping. The phenotype – the external appearance of a plant – includes, among other things, biomass, leaf size, leaf arrangement, flowering, and fruit development. “In plant breeding, phenotyping is crucial for identifying traits that should be passed on to the next generation,” says Fabian Keil. The goals are strong growth, robustness, and high yields.

For a comprehensive picture: Two- and three-dimensional imaging

For phenotyping, specialized sensor technology has been developed to capture plants in two and three dimensions using cameras. An algorithm then reconstructs a remarkably realistic digital twin from the raw data. In the future, the researchers also plan to use near-infrared data to obtain information that is invisible to the naked eye. The team is testing its findings at the Technology Center Phenotyping in Merkendorf, at the Weihenstephan-Triesdorf University of Applied Sciences.

In a controlled environment, Fraunhofer IIS tests a wide range of environmental conditions. Across an area of 1,000 square meters, scientists can adjust light intensity and spectrum, CO₂ levels, temperature, humidity, fertilization, and irrigation in three climate chambers. Plant pots are transported to the measurement stations via a conveyor belt. The system is designed to accommodate as many as 400 plants, each up to 2.5 meters tall and one meter in diameter. In addition to optical 2D and 3D detection, the team in Merkendorf draws on many years of experience in X-ray technology.

A look beneath the surface – X-ray technology makes it possible

While cameras capture the visible, above-ground parts of the plant, X-ray Computed Tomography (CT) scanning produces images of underground structures, such as the root system and the beet itself. This makes it possible to include otherwise invisible parts of the plant in phenotyping without having to dig it up. “This is probably unique worldwide that we can create three-dimensional reconstructions of plants both above and below ground without affecting their growth or causing any damage,” says Keil.

Collaboration with Strube: Correlating controlled-environment and field data

The Fraunhofer team conducted the experiment in collaboration with Lower Saxony–based seed producer Strube. The company continuously works on improving its seed varieties and has traditionally relied mainly on field data from real-world trial plots. “The comparison showed that data from our controlled environment correlate with field data,” says Keil. This demonstrates that the results can, in principle, be transferred to agricultural production. Using experiments conducted in a controlled environment, Strube can now selectively identify genetic lines and combine them to breed varieties that, for example, maintain consistently high yields even under drier environmental conditions.

»We want to be able to carry out the same kind of analysis for other crops as well.«

Dr. Fabian Keil

In the current experiment, researchers were able to demonstrate the relationship between irrigation and phenotypic traits in sugar beet: plants with a high water supply not only produced the greatest beet biomass, but also had the largest and most clearly visible leaf area. Fabian Keil is now looking to the future. “We want to be able to carry out the same kind of analysis for other crops as well,” says the group manager. In addition to the effects of drought stress, which were the focus of the experiment with Strube, the team at the Technology Center Phenotyping also aims to address pests and diseases in future studies.

Article by Julian Hörndlein, freelance journalist and PR writer