Survival of Rhizobia on Pelleted Seeds of Trifolium Subterraneum L.¹

Abstract

When Rhizobium trifolii was inoculated into 13 seed pellet coating materials, a wide variation in survival of the organisms was found. Five of six adhesives examined supported rhizobia growth. A tenfold improvement in rhizobia survival was obtained on pelleted subterranean clover seeds when the rhizobia were suspended in peat rather than broth. Only one of seven pelleting treatments using a peat suspension of rhizobia in 40% gum arabic had adequate numbers after 8 days.

THE SURVIVAL ON SEED OF RHlZOBIUM MELILOTI FROM COMMERCIAL INOCULANTS

“…While the counting methods used here may not recover every rhizoibial cell from th& surface of a seed, techniques used in this study have been ,applied successfully elsewhere (Radcliffe et al, 1967)) and the fact that in a number of cases almost all the lo-20 000 rhizobia/seed calculated to be present were found suggests that the counting method is reliable and the rapid reduction in viab!e cells shown is a real effect. There are numerous reports in the literature of rapid death of rhizobia on various surfaces (Vincent, 1958;Vincent et aI., 1962;Date et af., 1965) but it is usually considered that peat-based inoculants give a considerable measure of protection to the rhizobia on the seed surface.…”

“…All counts were made on duplicate samples of seed or inoculant. Counting: Each sample, 1 ml oJ suspended inoculant or 100 seeds, was suspended in 100 ml of sterile distilled water and shaken vigorously on a wrist action shaker for 20 minutes (Radcliffe et al, 1967) . From this suspension a tenfold dilution series was prepared and four plant tubes at each level inoculated with 1 ml of suspension (Date and Vincent, 1962).…”

Effects of Lime and Lime-Pelleted Seed on Legume Establishment and Growth in South Brazil

“…Various detriments to Rhizobium survival after sowing inoculated legume seed have been cited, including toxic effects of acid soils (Radcliffe et al, 1967;Brockwell, 1963). Pelleting the seed with lime before sowing has been suggested by a number of workers (Anderson et al, 1956;Brockwell, 1962;Loneragan et al, 1955), to overcome unfavourable soil conditions and to prolong Rhizobium survival for subsequent nodulation.…”