Abstract
As climate change progresses, the breeding of drought-tolerant forest trees is necessary. Breeding drought-tolerant trees requires screening for drought stress using a large number of individuals and a high-throughput phenotyping method. The aim of this study was therefore to establish high-throughput methods for evaluating the clonal stress responses to drought stress using infrared thermography and chlorophyll fluorescence methods in Cryptomeria japonica. The stomatal conductance index (Ig), maximum photochemical quantum yield of photosystem II (Fv/Fm), and axial growth of four plus-tree clones of C. japonica planted in pots were measured weekly for 85 days after irrigation was stopped. The phenotypic trait responsivity to drought stress was estimated by a nonlinear mixed model and by introducing the cumulative water index, which considers the past history of the soil water environment. These methods and procedures enabled us to evaluate the clonal stress responses in C. japonica and could be applied to large-scale clone materials to promote the breeding program for drought tolerance.
Highlights
The frequency of extreme climatic events, such as droughts and heatwaves, is expected to increase as the global climate change progresses [1]
We investigated the clonal variation in growth, stomatal response, and photosynthesis activity in response to drought stress among plus-tree clones of C. japonica using a high-throughput phenotyping method based on infrared thermography and chlorophyll fluorescence
Provided that dry reference leaves are prepared with care, high-throughput measurements using infrared thermography are well-suited for estimating stomatal conductance in C. japonica with its complex steric needles
Summary
The frequency of extreme climatic events, such as droughts and heatwaves, is expected to increase as the global climate change progresses [1]. When breeding for drought resistance, morphological traits, such as growth, yield, and mortality, and physiological traits, such as water use efficiency (WUE), stomatal conductance, cavitation of conductive tissue, photosynthetic ability, leaf wilting, leaf water potential, and osmotic regulation, are used as target traits. Most of these traits require considerable effort and time to measure and are not suitable for large-scale screening in breeding programs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
