Survival of several Rhizobium/Bradyrhizobium strains on different inoculant formulations and inoculated seeds.
The effect of a variety factors on the survival of several rhizobia strains on inoculants and inoculated seeds has been evaluated. Since the rhizobia strains showed different cell-density-evolution patterns on peat-based inoculants and on inoculated seeds, several inoculant formulations with highly effective Rhizobium/Bradyrhizobium strains (for Lupinus, Hedysarum, Phaseolus and Glycine max.) were monitored under the following storage conditions: (a) the inoculants were kept refrigerated (at 4 degrees C), or (b) at room temperature (25 degrees C). The effect of water content (30-50%, w/w) in the inoculants as well as that of several seed-coating adhesives were also investigated. Alternative carriers including perlite and vermiculite were tested. For all of the strains, survival on sterile peat-based inoculants was higher than on the corresponding unsterile peat formulation; for the latter, refrigerated storage conditions are recommended to ensure high bacterial densities. The water content of the inoculants had a differential effect on strain survival depending on the sterility of the peat, such that a high water content was more detrimental when unsterilized peat was employed. The best adherent for rhizobia survival was a gum arabic/water solution. Perlite was as effective as peat in maintaining a high population of rhizobia, at least for 6 months of storage.
CIFA Las Torres y Tomejil, Apartado Oficial, Sevilla, Spain.
F J
FJ
Temprano
M
M
Albareda
M
M
Camacho
A
A
Daza
C
C
Santamaría
D Nombre
DN
Rodríguez-Navarro
D001709:Biotechnology / Q000379:methods; D020369:Bradyrhizobium / Q000254:growth & development / Q000502:physiology*; D007306:Insecticides; D012231:Rhizobium / Q000254:growth & development / Q000502:physiology*; D012639:Seeds / Q000382:microbiology*; D012988:Soil Microbiology; D013696:Temperature
D007306:Insecticides