Volume 25, 47

Tropical Grasslands (1991) Volume 25, 47–55

Nitrogen fixation in Desmanthus: strain specificity of Rhizobium and responses to inoculation in acidic and alkaline soil

R.A. DATE

Division of Tropical Crops and Pastures, CSIRO, Brisbane, Queensland, Australia

Abstract

Forty-eight accessions of Desmanthus (1 each of D. brevipes, D. fruticosus, D. illinoensis, D. subulatus, 2 of D. covillei and 42 of D. virgatus) were screened against 17 strains of Rhizobium for effectiveness of N-fixation. Six effectiveness groups were defined by pattern analysis with 23 accessions forming effective associations With 10 or more strains.
Five accessions selected previously for their agronomic potential responded to inoculation, especially in acidic soil. Over all strain treatments, D. virgatus CPI 38351 and TQ 90 out-yielded (dry weight and N content) the other accessions. Proportional differences among host accessions were greater in the acid podzolic soil from Gympie than in the alkaline heavy clay soil from Gayndah. In the Gympie soil strains CBI 397 and CB 3126 were significantly better on accession CPI 38351 but only CB 3126 was better on TQ 90. These results show that there are suitable strains of Rhizobium for adapted lines of D. virgatus for use in S.E. Queensland