An Intermediate Category of Seed Storage Behaviour?

Seeds of four cultivars of arabica coffee (Coffea arabica L.) were tested for germination following hermetic storage for up to 12 months at several different combinations of temperatures between −20 °C and 15 °C and moisture contents between 5% and 10% (wet basis). Most of the seeds from one cultivar withstood desiccation to between 5% and 6% moisture content, a seed water potential of approximately −250 MPa, but those of the remaining three cultivars were much more sensitive to desiccation damage. Moreover, in all four cultivars, seed longevity at cool and sub-zero temperatures, and at low moisture contents did not conform with orthodox seed storage behaviour: viability was lost more rapidly under these conditions than at either warmer temperatures or higher moisture contents. The results confirm that coffee seeds fail to satisfy the definitions of either typical orthodox or recalcitrant seed storage behaviour. These results, therefore, point to the possibility of a third category of storage behaviour intermediate between those of orthodox and recalcitrant seeds. One of the main features of this category is that dry seeds are injured by low temperatures.