Promotion of peanut growth by co ?inoculation with selected strains of Bradyrhizobium and Azospirillum.

VICARIO JULIO; PRIMO EMILIANO; DARDANELLI MARTA; GIORDANO WALTER

JOURNAL OF PLANT GROWTH REGULATION

SPRINGER

Lugar: Berlin; Año: 2016 vol. 35 p. 413 - 419

0721-7595

The ability of inoculated rhizobial strains toincrease root nodulation of host legumes often depends ontheir competitiveness with existing native soil strains.Results of studies to date on rhizobial inoculation forimprovement of peanut (Arachis hypogaea L.) productionin Argentina have been inconsistent and controversial. Inmany cases, nodulation and yield of peanut crops havebeen increased by inoculation of specific rhizobial strains.Native peanut-nodulating strains are generally present insoils of agricultural areas, but their growth-promotingeffect is often lower than that of inoculated strains. Manyspecies of the genus Bradyrhizobium interact in a hostspecificmanner with legume species and form nitrogenfixingroot nodules. Other free-living rhizobacteria such asspecies of the genus Azospirillum are facultatively capableof interacting with legume roots and promoting plantgrowth. We evaluated and compared the effects of varioussingle inoculation and co-inoculation treatments on peanutgrowth parameters in greenhouse and field experiments. Inthe greenhouse studies, co-inoculation with variousBradyrhizobium strains (native 15A and PC34, and recommendedpeanut inoculant C145), and Azospirillumbrasilense strain Az39 generally resulted in increases in themeasured parameters. The growth-promoting effect of 15Awas similar to or higher than that of C145. In the fieldstudies, 15A-Az39 co-inoculation had a greater promotingeffect on measured growth parameters than did C145-Az39co-inoculation. Our findings indicate that careful selectionof native rhizobacterial strains adapted to peanut soils isuseful in strategies for growth promotion, and that 15A inparticular is a promising candidate for future inoculantformulation.