The interrelation of age, permeability and viability of subterranean clover seeds

Abstract

The proportions of impermeable seeds, and the viability of permeable and impermeable seeds were measured in samples of Trifolium subterraneum seed that had been stored in a laboratory for up to 34 years. Viability of permeable seed decreased from 99 per cent after storage for 1 year to 8 per cent after 30 years. On the other hand, all impermeable seeds were viable for 1 to 5 years, and 83 per cent were viable after 30 years. The impermeable seed content of the older seed lots was generally higher than that of the younger ones. This difference was related to the high retention of impermeability of the seeds during storage, and to changes in the severity of threshing methods. The impermeable seed content was also correlated positively but poorly with the viability of both permeable and impermeable seeds, independent of the age of the seed. These associations are probably due to the common effect of the environment on all these variables during seed ripening. A small varietal component in each variable was detected. The implications of these data for the long-term storage of small samples of seed are discussed.