With the global demand for agricultural productivity increasing annually, it is becoming increasingly important to enhance efficiency and crop quality in order to improve food security.

Traditionally, the quality evaluation of agricultural produce has relied on manual inspection. This method is often insufficient as it focuses primarily on external features, and can be time-consuming, laborious, and costly. Moreover, characterizing internal structures requires destructive techniques, preventing further analyses and germination.

Over the last decade, there has been a significant interest in utilizing non-destructive quality evaluation methods for agricultural products. These methods aim to improve the speed of quality check, remove subjective bias, and increase reliability and sustainability. Such techniques are critical in today's agricultural landscape, where efficiency and precision are paramount.

X-ray technology has emerged as a valuable tool in this domain, providing precise insights into the quality of seeds and plants. The advancements taking place in the X-ray imaging space has expanded its applicability beyond medical diagnostics into various industries, including agriculture and seed science. X-ray technology can be used to select seeds with desirable characteristics for breeder seeds and foundation seeds. Furthermore, X-ray imaging aids in the early detection of diseases and infestations, allowing for timely interventions that can drastically reduce losses. X-rays are also widely used for sterilization, to improve food safety. These recent developments have demonstrated the potential impact of X-rays on agricultural practices.

Here, we explore the significant role X-ray imaging plays in modern agriculture, highlighting its various applications and benefits.

Applications of X-ray Imaging to Advance Agricultural Efficiency

Quality assessment is essential for achieving high yields, saving time, and ensuring cost efficiency. Accurate evaluation of the quality of seeds and produce, can help agriculturists optimize their resources and maximize their returns. The International Seed Testing Association (ISTA) has established standardized methods to assess seed quality, focusing on genetic and physical purity, germination capacity, and sanitary analysis.

X-ray imaging has become a popular phenotyping tool, enabling qualitative and quantitative analysis of internal characteristics in seeds, grains, nuts, fruits, plants, and soil. Its applications include internal quality evaluation, microstructure observation, mechanical property measurement, and product classification. X-ray technology helps identify the precise site and extent of damage within seeds, fruits and plants, such as cracks, infestations, and tissue and cellular damage. This information is crucial for quality control, improving decision-making in seed selection, and optimizing overall agricultural efficiency.

Seed Quality

Seed quality determination involves inspecting both the internal and external conditions of seeds to determine viability and locate any damage (be it surface level or not). Methods such as embryo excision, indigo carmine staining, and tetrazolium staining are destructive and time-consuming. X-ray imaging, on the other hand, provides results in under a minute, non-destructively, making it ideal for seed companies and seed libraries.

FIGURE 1 Images acquired non-destructively using the KUBTEC® Parameter® X-ray System, which indicate the seed fill of watermelon seeds.

Radiation imaging techniques and modalities such as X-ray microscopy, micro-CT, and digital X-ray imaging, allow for the evaluation of internal parameters such as density, stage of development, and tissue deterioration. These technologies facilitate the analysis of the seed coat, endosperm (cotyledons), and embryo features which are critical factors in seed quality determination. Additionally, understanding the microstructure of grains, including porosity, connectivity index, and cell wall thickness distribution, could be useful for crops like rice and wheat.

For instance, r that wheat grains of different strains could be distinguished based on differences in starch granule shapes and pore shapes using X-ray . To date, X-rays have been successfully applied to determine the internal quality of a variety of seeds, including maize, watermelon, tomato, ponderosa pine, and more.

Insect Infestation and Contamination

X-ray imaging is a powerful tool for detecting insect or fungal infestations and contaminants in plants and seeds which can hinder seed germination and affect yield. Insect infestations are also known to increase the risk of aflatoxin contamination, a carcinogenic toxin produced by fungi, on crops like maize, peanuts, cottonseed, and tree nuts.

FIGURE 2 Image acquired on the KUBTEC® XPERT® 80 X-ray Imaging System to determine whether weevils were present.

FIGURE 3 Prunus Avium imaged using a KUBTEC Parameter X-ray Imaging System to determine presence or absence of an infestation.

X-ray imaging ha been successfully employed to precisely identify the stage of infection in various plant parts and detect contamination in saplings, seeds, fruits, or horticultural peat. When compared with other physical methods, X-ray imaging wfound to be the most effective at detecting early stages of insect infestations in grain. Furthermore, image intensity histogram-based approaches have been useful in identifying the type of insect infestation in tree nuts. Interestingly, researchers haveemployed X-ray imaging to study insect behavior, for example in pecan nuts.

Plant Morphology and Physiology

FIGURE 4 IMAGE OF A WATERMELON SEED TAKEN ON AN XPERT 80 SHOWING THE DIFFERENT DEVELOPMENT STAGES OF THE TWO EMBRYOS

X-ray imaging helps visualize plant tissues and organs, a step that is critical to the study of plant development, organ formation, transport processes, and fossils. Notably, X-rays are apt in distinguishing plant features that have significant density differences, such as seeds, cellular structures, calcium oxalate crystals, grafts, leaf structures in resurrection plants, and vasculature.

By examining various species in unique environments, this technique also supports advanced genetic research. Moreover, researchers are exploring correlations between vast structural and morphological plant data and other factors such as metabolite content, pollination, and crop yield.

X-ray Sterilization

X-rays are playing a critical role in applications like plant and seed sterilization and have been used to induce mutagenesis in plant breeding programs. In an experiment, when peanut seeds were exposed to X-ray at 45 KeV for 5 seconds, they showed a high reduction of stem rot and an improvement of yield and seed oil content. Unlike chemical sterilization methods using ethylene oxide, which is carcinogenic and leaves harmful residues, or methyl bromide, which poses significant environmental risks, X-ray radiation is a safer, more environmentally friendly alternative. It effectively eliminates harmful pathogens and pests, and increases shelf life by delaying ripening and sprouting. KUBTEC’s line of x-ray irradiators, the XCELL® product line, is currently available in sources ranging from 50-320 kV.

What the Future Looks Like for Agriculture

The integration of X-ray imaging technology into agricultural practices marks a significant leap towards achieving higher efficiency and superior crop quality. As we enter the era of artificial intelligence (AI) and big data, what's next?

Recent studies have demonstrated the potential of deep learning models for defect detection. These AI-based analyses are already being applied to 2D X-ray radiography, offering a faster and more robust method for identifying both defective and defect-free seeds. The future holds the promise of automatic detection of seed defects and plant classification, revolutionizing agricultural practices.

At KUBTEC Scientific we have been monitoring these emerging needs and applications closely, developing solutions to meet industry needs. As a result, we have a broad, versatile range of cabinet-based imaging and irradiator systems. The current suite of offerings includes solutions in benchtop and freestanding formats, with multiple x-ray sources and detector sizes available. Each product is quoted with optional features to ensure solutions are optimized for each customer’s research requirements.

We offer a range of systems suited for agriculture imaging:

• The XPERT® 20 Benchtop X-ray System- is a compact benchtop solution that is ideal for small volume seed analysis and features a 3" x 5” detector
• The PARAMETER® X‑ray Systems are a product family made of three imaging cabinets. Users are able to select between the PARAMETER 2D Imaging System, PARAMETER 3D Tomosynthesis System, or the PARAMETER Supra Imaging System. Based on the selected model, users can acquire over a 6" x 5" or 12" x 10" imaging area, equipped with either a 50 kV or 90 kV source. The Supra offers KUBTEC's best possible resolution.
• The XPERT® 80 X‑ray System- our medium sized solution for seed analysis – available in a 5" x 6” or 10" x 12” format with either a 50 kV or 90 kV source
• The XPERT® 80-L X‑ray System- our large format solution for seed analysis – available in a 17" x 17” format for high throughput analysis

Not sure which model is best for you? Contact our team by clicking here.

Given concerns over radiation exposure, and the desire to abandon cumbersome external lead shielding, the housing on each of KUBTEC's systems is fully shielded. Unlike other imaging methods, no special training or certifications are required for operation. During installation, our team comes on-site and performs a Radiation Survey to ensure safe conditions. Oftentimes, this survey satisfies the safety and compliance requirements set forth by many facilities.

The PARAMETER®, XPERT 80®, and XPERT 80-L® feature our proprietary feature Image Blender™. With Image Blender, users acquire both an X-ray and optical image at each acquisition which are then seamlessly overlain, to provide valuable information about the seed characteristics or something as simple as a label on a bag or container. Within the seed science industry, this can be a time saving tool to easily track sample information as shown below.

X-Ray

Optical

The Image Blender™

Images can intuitively be manipulated using our DIGISEED® Seed Analysis Software. Given the need for increased throughput and all-around productivity improvements, our team has been focused on adding functionalities that drive efficiency. Here is a sampling of some of DIGISEED’s current  functionalities:

• Automatic seed counting
• Seed percent fill
• Seed density
• Seed size measurements