High-throughput phenotyping approach for the evaluation of heat stress in Korean ginseng (Panax ginseng Meyer) using hyperspectral reference image

Authors: PARK, EUNSOO - Chungnam National University; KIM, YUN-SOO - Chungnam National University; OMARI, MOHAMMAD - Chungnam National University; SUH, HYUN-KWON - Dong-A University; FAQEEZADA, MOHAMMAD - Chungnam National University; Kim, Moon; BAEK, INSUCK - Orise Fellow; CHO, BYOUNG-KWAN - Chungnam National University

Submitted to: Sensors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2021
Publication Date: 8/21/2021
Citation: Park, E., Kim, Y., Omari, M., Suh, H., Faqeezada, M., Kim, M.S., Baek, I., Cho, B. 2021. High-throughput phenotyping approach for the evaluation of heat stress in Korean ginseng (Panax ginseng Meyer) using hyperspectral reference image. Sensors. 21:5634. https://doi.org/10.3390/s21165634.
DOI: https://doi.org/10.3390/s21165634

Interpretive Summary: Heat stress is a challenging and significant threat to plant growth and sustainable production of Panax ginseng. Classification models based on visible and infrared hyperspectral imaging (HSI) of young seedlings of three varieties of ginseng were developed for nondestructive evaluation of plant susceptibility and resistance to heat stress, with comparison to color imaging. HSI outperformed color imaging, demonstrating high accuracy differentiation of normal and heat-stressed plants with spectral correlations to physiological effects on plant photosynthesis and metabolism that cannot be detected by exterior color imaging. The results show that visible and near-infrared HSI method has great potential in helping ginseng producers with crop growth management and in breeding of plants resistant to heat stress, for higher quality and more sustainable production of a medicinally/pharmacologically important plant.

Technical Abstract: Panax ginseng has been used as a traditional medicine to strengthen human health for centuries. Over the last decade, significant agronomical progress has been made in the development of elite ginseng cultivars, increasing their production and quality. However, as one of the significant en-vironmental factors, heat stress remains a challenge and poses a significant threat to ginseng plants' growth and sustainable production. This study was conducted to investigate the pheno-type of ginseng leaves under heat stress using hyperspectral imaging (HSI). A visi-ble/near-infrared (Vis/NIR) and short-wave infrared (SWIR) HSI system were used to acquire hy-perspectral images for normal and heat stress-exposed plants, showing their susceptibility (Chunpoong) and resistibility (Sunmyoung and Sunil). The acquired hyperspectral images were analyzed using the partial least squares-discriminant analysis (PLS-DA) technique, combining variable importance in projection and successive projection algorithm methods. The correlation of each group was verified using linear discriminant analysis. The developed models showed 12 bands over 79.2% accuracy in Vis/NIR and 18 bands with over 98.9% accuracy at SWIR in vali-dation data. The constructed beta-coefficient allowed the observation of the key wavebands and peaks linked to the chlorophyll, nitrogen, fatty acid, sugar, and protein content regions, which differentiated normal and stressed plants. This result shows that the HSI with the PLS-DA tech-nique significantly differentiated between the heat-stressed susceptibility and resistibility of gin-seng plants with high accuracy.