A study was carried out to test whether a single count of radicle emergence (RE test) would correlate with the storage potential of seed lots of cucurbit (C. maxima x C. moschata) rootstock cultivars. The RE test was performed by counting radicle emergence percentage between 26 and 100 hours of germination. Seed longevity was determined by storage at 75% relative humidity at 35 degrees C over 100 days, with seed survival curves constructed based on normal germination percentages. K-i (estimated initial viability in probits), sigma (standard deviation of the normal distribution of seed death in time) and p(50) (time for viability to fall to 50%) were determined through probit analysis. Correlation analysis showed that RE counts particularly between 30 and 34 hours were highly (P < 0.01) correlated with normal germination percentage, K-i and p(50). It can be concluded that RE tests can be used as an indicator of subsequent seed lot longevity in cucurbit rootstock seed cultivars.