Discriminating Spectral Signatures Among and Within Two Closely Related Grapevine Species

Several North American Vitis species are used to breed scions and rootstocks, including V. riparia and V. rupestris. However, the degree to which Vitis species can be distinguished using remote sensing is not well known. Here we explore whether two North American Vitis species and genotypes growing in a common garden can be discriminated with leaf and canopy hyperspectral reflectance factor data (350-2500 nm) using independent t-test and derivative analysis. Foliar properties and spectral indices of the grapevines were evaluated with analysis of the variance (ANOVA) and pair-wise Bonferroni adjusted t-tests. The results showed that V. riparia and V. rupestris can be distinguished at the leaf level spectra of visible, near- and infrared spectral regions. At the canopy level, genotypes were spectrally discriminated with limited success. The Photochemical Reflectance Index (PRI) demonstrated the highest potential not only to differentiate two species, but also two genotype pair groups within V. rupestris. This finding was also true for the PRI calculated with simulated EO-1 Hyperion data. These capacities to distinguish Vitis species, and to a lesser extent genotypes, using spectral signatures have important applications in remote monitoring of vineyards for plants health and also for locating wild Vitis populations for future crop improvement efforts.