Phenotyping plant characteristics is an important area of research. Not only does it aid with plant breeding and crop management, but also provides insight into the biology of plants in their natural environment.
Phenotyping is becoming more automated and standardised, yet its application still needs improvement. This has been illustrated by a recent analysis of plant phenotyping research.
What is phenotyping?
Plant phenotyping is the quantitative description of a plant's anatomical, ontogenetic, physiological and biochemical characteristics. It's essential for understanding plant function in order to increase crop yields and safeguard human health and welfare.
Phenotyping a plant refers to the series of changes that take place throughout its lifespan, from DNA transcription (transcriptomics) through RNA formation and protein synthesis (proteomics). These processes are influenced by different metabolites and ions produced from within the cell's metabolic pathway as well as environmental elements like stress.
Over the last decade, there has been significant advancement in non-destructive image-based phenotyping that has taken us from small-scale characterizing individual traits to large applications in field. It now uses technologies such as thermography point sensors and remote sensing to characterize vegetation characteristics at high throughput rates.
To chart the progression of plant phenotyping research in scientific publications, we used the Scopus database to retrieve bibliographic records related to this field from 1997-2017. Figure 7 depicts a world term year map showing early publications primarily representing genetics and metabolism (represented by blue and green clusters), while more recent works are more closely tied to imaging technologies and plant-environment interactions as indicated by red clusters.
What is the purpose of phenotyping?
Plant phenotyping is the practice of measuring and analyzing plant characteristics to increase yield. This practice has been practiced by farmers and breeders for more than 5,000 years, since humans began selecting traits to maximize production.
Recent advances in phenotyping have enabled researchers to conduct large-scale, automated analyses of plant traits. This allows them to link phenotypes with genomic information, enabling fast and efficient breeding efforts for desirable genotypes such as salt-tolerance or drought resistance in wheat or barley.
Phenotyping is used to detect and assess differences in crop growth, development, architecture, physiology, ecology and yield. Through non-destructive image-based techniques these traits can be measured at various spatial and temporal scales and related to genome data.
What are the limitations of phenotyping?
Phenotyping technologies are essential tools in plant research. They allow us to determine the structure and function of seeds, roots, root systems, storage organs above-ground and below-ground, leaves, flowers, fruits – you name it! Phenotyping technologies provide invaluable insights into plants!
However, several limitations prevent phenotyping techniques from yielding accurate results. These include size restrictions, occlusions, and difficulty in creating a 3D model that accurately represents an object in space.
These challenges can be solved using an image-based approach, in which a camera system captures images from different viewpoints and then reconstructs 3D models of the plant. Compared to rule-based approaches, image-based models better capture plant structure as well as their environment.
Additionally, these techniques can be employed to measure a wide range of traits which are then linked to genes responsible for them in genome-wide association studies (GWAS). This has allowed scientists to unravel complex plant genetic architectures and facilitate crop breeding efforts.
What are the potential applications of phenotyping?
plant phenotyping is an invaluable resource for research, breeding and precision agriculture. It provides a quantitative description of a plant's anatomical, ontological, physiological and biochemical characteristics.
It allows to comprehend the interaction between a genotype and its environment. This information is useful when managing crops or studying the effects of biostimulants, microbial communities or other sources of plant stress [3, 4].
Breeding and genetics require hundreds of measurements to select superior individuals or identify regions in the genome responsible for a trait. To accomplish this goal, high-throughput phenotyping must be achieved via automated platforms that capture thousands of plant images daily.
After 15 years of development, non-destructive image analysis based plant phenotyping is beginning to show its value in basic science as well as crop breeding and precision agriculture. However, a holistic approach of plant phenotyping is yet to be fully utilized.