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.