Role of epicuticular wax in the regulation of plant growth and health as measured by spectral indices

Using remote sensing technology for exploring the trait of interest can provide better results without damaging the plants and are comparatively economic. Traditional methods are available for quantification of different pigments and chemicals present in plants, yet these methods do not allow repeated measurements on the same plant throughout development. The reflected values from plant surfaces are a direct representation of plant physiology including plant morphological factors. The hyperspectral imaging indices for vegetation and water-stressed canopies provided a better indication of each genotype proficiency, thus improving their selection efficiency. The presence of epicuticular wax (EW) influences the reflectance from leaf surface which depends on the presence of leaf pigments including carotenoids, photosynthetic light use efficiency biochemical structures, and water content as they absorb the incident light necessary for photosynthesis. The results obtained suggested decrease carotenoid reflectance index (CRI) and photochemical reflectance index (PRI) values for high wax lines indicating the low concentration of stress-related pigments thus improving plant health and extended maturation. The high waxy lines decreased for plant senescence reflectance index (PSRI) and reduce canopy stress at grain filling and maturation growth stages. A positive correlation between high epicuticular wax (EW) and yield was found confirming previous study. A positive correlation between high epicuticular wax (EW) lines and yield indicated its important role in preventing yield losses under drought conditions.