Fig. 1.

Dendrogram of an unsupervised hierarchical cluster analysis of rhizobial strains isolated from cowpea nodules based on Dice distances of mass spectral protein profiles of Matrix Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) Mass Spectrometry (MS). Presence/absence of protein masses in the size range of mass-to charge ratio (m/z) 3000–12,000 was used. Strain origin is indicated in the strain identifiers (K: Kilifi, M: Mbeere). The strains 1–15 are from cultivated sites and the strains 16–20 from uncultivated sites. Reference strains were the isolates CBA from commercial Biofix inoculum (MEA Ltd. Nakuru, Kenya) and BK1 from a trap culture with soils from Burkina Faso. The scale bar shows the Dice distance in per cent.