Discrimination between Betula pendula, Betula pubescens, and their hybrids using near-infrared reflectance spectroscopy

Identification of Betula pendula Roth, Betula pubescens Ehrh.; and their interspecific hybrid is a long-standing problem. We present a methodology in which dried, milled leaves of a sample of the three taxa have been subjected to near-infrared reflectance spectroscopy at a broad range of wavelengths (400-2500 nm). Discriminant analysis of selected spectral wavelengths has yielded discriminant functions that allow correct classification of all cases. in addition, it shows that the interspecific hybrid is biochemically more similar to B. pubescens than to B. pendula, which is in accord with the generally reported morphological similarity. The value of this method in enabling interspecific hybrids to be identified in natural populations is discussed. The demonstration that arch discrimination is possible with near-infrared spectral data may lead to the possibility of identifying the species and hybrids by remote sensing or with a field instrument.