COMPARATIVE EFFECTIVENESS AND COMPETITIVE ABILITY OF BRADYRHIZOBIUM STRAINS FOR STYLOSANTHES HAMATA

摘要

Stylo (Stylosanthes hamata) is an important pasture legume for arid and semiarid regions. It has the potential to withstand adverse conditions and could provide a substantial forage resource with limited crop management practices. The Na fixation is highly dependent on the microbial strain as often inoculation with a highly effective exotic strain of Rhizobium may not always produce desired gains on account of predominance of highly competitive, though less effective local strains of Rhizobium in soil. The provision of superior strains for use in inoculants remains the primary applied contribution from the field of biological Na fixation. In addition to selecting strains which are highly effective and efficient at Na fixation with a given legume genotype, Brockwell ef al. (1982) list 10 other important attributes, of which the first two are: competitive ability, and Na fixing ability over a range of environmental conditions. Thus, the strains to be applied beside efficient should be most competitive in nodule formation and persistent in a particular field environment. Against this goal, the present experiment was undertaken to find out the relative efficacy of the exotic and native strains and their extent of competitiveness on Stylosanthes hamata.