2025 Volume 63 Issue 3 Pages 65-71
This study aimed to enhance the practicality and broaden the applicability of root phenotyping by reducing the cost of the hyperspectral imaging method proposed by Jin et al. (2025). To do so, we evaluated the feasibility of using a low-cost multispectral camera for the in situ monitoring of root growth and age in spinach (Spinacia oleracea L. cv. “Wase Kurone Horenso”) in a transparent hydroponics system. For this setup, plants were grown for 40 days, and root images were captured using the multispectral camera with 41 bands (i.e., 450–850 nm at 10 nm intervals). Root-background separation was subsequently performed based on reflectance intensity ratios, and a root age classification index for the multispectral camera was developed by analyzing the correlation between the reflectance intensity ratio and root age. Additionally, the index previously derived for hyperspectral camera (Jin et al., 2025) was applied for comparison. Relative to hyperspectral imaging, multispectral imaging demonstrated a comparable ability with respect to monitoring root growth and age distribution dynamics while significantly improving accessibility and robustness by reducing cost of the instrument, measurement time, and data processing. These findings highlight the potential of multispectral imaging as a practical alternative for nondestructive root monitoring in actual agricultural production.
