Abstract Recurrent half-sib selection within a heterogeneous population of cucumber ( Cucumis sativus L.) was effective in improving germination at 15°C from 34.4% in cycle 0 to 92.4% in cycle 3. The linear regression coefficient indicated an average increase of 19.8% units per cycle of selection. Correlated responses to selection resulted in increased percentage of germination at 20° and 25° and decreased days to germination at 15°, 20°, and 25°.