Efficacy of rhizobia strains on growth and chemical composition of cancer bush (Sutherlandia frutescens)

ABSTRACT Cancer bush (Sutherlandia frutescens), which is facing extinction, can be conserved through cultivation using best agricultural practices that include nodulation with effective rhizobia bacteria. The objective of the study was to compare the efficacy of commercial and native nodulation bacteria on productivity of S. frutescens over two seasons. Seasonal interaction on productivity variables was not significant (P < 0.05), with pooled data (n = 75) subjected to analysis of variance. Treatments had a significant effects on plant variables, contributing from 58 to 91% in total treatment variation (TTV) of the variables. Relative to untreated control, commercial strains significantly increased plant variables from 31 to 44%, whereas wild strains increased the variables from 17 to 195%. Similarly, both commercial and native strains significantly increased nitrogen, protein and symbiotic efficiency, with magnitudes of native strains being significantly higher than those of commercial strains. Treatments had no significant effects on K and protein in leaf tissues of S. frutescens. In conclusion, the native strains as investigated in the current study have the potential for use in the husbandry of cancer bush.