Drought tolerance phenotyping using thermal imaging : high throughput phenotyping of Pinus sylvestris

Abstract: Climate change is an emerging problem in the world. One of the many challenges that comes with it is an increase of droughts. Droughts cause stress for plants, which impact the growth. An important stage for trees is the seedling stage, and an important tree in the forest is the Scots pine (Pinus Sylvestris), therefore this study will focus on these. High throughput phenotyping is a tool that can help identifying drought tolerance. In this paper the use of thermal imaging as a way to achieve high throughput phenotyping in Pinus sylvestris for transpiration and its links to drought tolerance was evaluated. Another possible phenotyping method, used in this study, is if drought tolerance can be evaluated by their divergence from an average growth. Experiment took place during the summer of 2022 and plants evaluated started growing that same year. It took place inside a greenhouse and with a drought/control treatment. The results revealed differences between natural and bred plant material, and also between northern and southern plant material. With bred and southern plants expressing lower stress compared to the others. A strong negative association between total volume and canopy temperature for drought treated plants suggest there is potential for using infrared light to evaluate drought tolerance. Also consistent patterns between the transpiration and divergence from average growth supports the idea that thermal imaging could be used for high throughput phenotyping.