Figure 7.

Cluster analysis of the Av-spectra of all cultivars of the species Pisum sativum (Ps, pea), Avena sativa (As, oat), Zea mays (Zm, maize) and all proveniences of the species Echinochloa crus-galli (Ec, barnyard grass) for the united experiment 1 (exp. 1-1 and 1-2) as well as the united experiment 2 (exp. 2-1 and 2-2). Cluster analysis was evaluated with the first derivation and vector normalization of the reduced frequency range (3,751–2,749 cm⁻¹ and 1,801–599 cm⁻¹), Ward's algorithm and Euclidian distance. The Av-spectra are averages (Av) of FTIR-ATR spectra of the different root segments (100% root tip, 0% root basis etc.; see Figure 1 for scheme, Table 2 for n, Table 1 for names of cultivars and proveniences).