The uptake of sucrose in vitro by the storage tissue of a number of sugar-cane clones in two field trials and one pot experiment was measured at different times and used to calculate the apparent free space (AFS) of the storage tissue. In general, the AFS of the storage tissue increased with age and was greater in storage tissue from higher quality clones. In one field trial positive and significant correlations were found between AFS versus 'sucrose percent cane'** (S) at each stage of development studied, as well as between the AFS at five months versus S and yield of sugar (TS ha-1) at 12 months. In the second field trial, significant correlations were found between AFS at nine months versus S at 12 months and between AFS at 12 months versus TS ha-1. The results, though inconclusive, suggest that the AFS as early as five months may be used to identify high quality clones.