High-resolution spectral information enables phenotyping of leaf epicuticular wax in wheat

Abstract Background Epicuticular wax (EW) is the first line of defense in plants for protection against biotic and abiotic factors environment. In wheat, EW associated with resilience to heat drought stress, however, current limitations on phenotyping restrict integration this secondary trait into wheat breeding pipelines. study we evaluated use light reflectance as a proxy load developed an efficient indirect method selection genotypes high density. Results Cuticular waxes affect that reflected, absorbed transmitted by plants. The narrow spectral regions statistically overlap bands linked photosynthetic radiation (500 nm), carotenoid absorbance (400 nm) water content (~ 900 indices predicted 65% (EWI-13) 44% (EWI-1) variation utilizing single-leaf reflectance. However, normalized difference EWI-4 EWI-9 improved efficiency canopy across all field experimental trials. Indirect led 70% compared chemical method. regression model EWM-7 integrated eight wavelengths accurately 71% (mg·dm −2 ) leaf reflectance, but under conditions, single-wavelength consistently estimated average RMSE 1.24 mg·dm ground aerial Conclusions Overall, EWI-1, EWI-13 are reliable tools based EWI-4, EWM-1 further research needed define how background effects geometry impact accuracy these methods.