The relationships between different vegetation indices and chlorophyll content index values (CCI) in strawberry leaves

Leaf chlorophyll is a key indicator of physiological condition of plants. The aim of the present study was to investigate the relationships between different vegetation indices and chlorophyll content index values (CCI) in strawberry leaves from two varieties Asia and Alba. Twenty- four different vegetative indices were calculated using measured reflectance spectra of leaves in visible and short-wave near-infrared region. It was found that CARI, MCARI, mNDVI, Clred edge, Clgreen, REI1, REI2, and REI3 indices are more sensitive to leave's chlorophyll content. Linear, quadratic, logarithmic and compound predictive regression models, defining the relations between the CCI and the investigated vegetation indices for both varieties of strawberries, were calculated. The Compound model based on calculated vegetative indices for the Alba variety has the best fit for all tested indices. The highest coefficient of determination of 0.743 was found for CARI index. Quadratic model best describes the relationship between CCI and the investigated vegetation indices for the Asia strawberry variety. The best fit was found for REI2 index – the obtained coefficient of determination was 0.842. The results of the study show that it is possible to use different vegetative indices obtained by nondestructive remote sensing methods to estimate the chlorophyll content in strawberry leaves.