The sensitivity of Fragaria seedlings to colchicine is dependent on the plant organ that is treated. Complete immersion of seedlings in a 1.5% colchicine solution results in total lethality, whereas the survival rates were more than 75% even at concentrations of 3.0% when only shoot apices were treated. High proportions of polyploids were isolated by treating shoot apices of seedlings with a 2.0% colchicine solution for 24–28 h. The ‘dropper’ method is preferred to the ‘tube’ method as it involves a minimum of manipulation and requires simple equipment. A differential response to colchicine was observed within and between different diploid species, diploid and tetraploid hybrids.