Survival of rhizobia on commercially lime-pelleted white clover and lucerne seed

Abstract

Survival of rhizobia on lime-pelleted white clover and lucerne seed was examined on 100 g samples stored at 20 °C in sealed plastic bags, and on 56 kg bulk samples stored under ambient conditions in a seed store. Clover rhizobia survived better on pelleted white clover than did lucerne rhizobia on lucerne. On seeds stored at 20 °C, rhizobial numbers fell to 10% of their initial values in 17-22 weeks (white clover) and 6-9 weeks (lucerne). The survival of rhizobia on pelleted seed stored at low temperature (5 and -15 °C) was also examined. Only 13.6% of the rhizobia initially detected remained viable on lucerne seed after 24 weeks at 5 °C. However, the number of rhizobia on white clover stored at 5 °C or -15 °C for 41 weeks, and on lucerne stored at -15 °C for 24 weeks did not decline detectably. The death rates of rhizobia on white clover seed returned to storage at 20 °C after storage at low temperature were significantly higher than the death rates for rhizobia on seed stored continually at 20 °C.

Keywords:

• Trifolium repens L.
• white clover
• Medicago sativa L.
• lucerne
• Rhizobium trifolii: R. meliloti
• inoculation
• lime-pelleting
• seed storage
• survival
• cold storage