Using radiation thermography to evaluate high temperature stress in cauliflower

Physiological disorder of high temperature causes red and purple spots on the surface of cauliflower curds, and bracts often protrude from the surface of the curd, which leads to a decrease in commercial value.
To understand how high temperature affects the physiological performance and curd surface of cauliflower, we used a thermal image camera to investigate leaf temperature combined with photosynthesis.
The results provide novel information to select heat-tolerant cultivars and improve production problems in summer in Taiwan.
Six early maturing type cauliflower cultivars including ‘H-37’, ‘Summer Cloud’, ‘Dung Summer 40 Days’, ‘Rich Farmer 45 Days’, ‘Fengshan No. 2’, and ‘Summer Day’ were used as testing materials.
The results showed canopy leaf temperature of ‘Rich Farmer 45 Days’ was lower than other cultivars by infrared thermography.
As compared with the relationship between leaf temperature and evapotranspiration rate, the evapotranspiration rate showed raised tendency as the increase of leaf temperature.
Both ‘Rich Farmer 45 Days’ and ‘Fengshan No. 2’ increased the evapotranspiration rate more than others under the same leaf temperature.
The ‘Summer Day’ can maintain a higher net photosynthetic rate during the curd development period under high air temperature, followed by ‘Dung Summer 40 Days’, ‘Summer Cloud’, and ‘Fengshan No. 2’. This research found that leaf temperature with photosynthesis and evapotranspiration rate would achieve the interactive relationship of temperature stress and physiology responses.
This method may provide an application tool at preliminary selection and breeding of heat-tolerant cultivars.
It is worth noting that the differences between environmental parameters and growth stages still need to be evaluated and verified to provide a basis for the improvement and development of new cultivars.

IV Asian Horticultural Congress – AHC2023

Chiao-Ling Hsiao, Chen-Yu Lin

evapotranspiration, heat, infrared image, leaf temperature, photosynthesis

https://doi.org/10.17660/ActaHortic.2024.1404.149