The developmental stage at which the pollens were collected,the 24-h pollen incubation and different concentrations of sucrose in the germination media all had profound effects on pollen tube growth, particularly for ‘cv. C’ (Fig. 1(1.2a), (1.4a) and (1.6a)). The highest pollen tube length of ‘cv. C’ (578.13 m; Fig. 1(1.6a)) was obtained when fresh pollen was cultured in the medium containing 5% sucrose, and the second longest (446.04 m; Fig. 1(1.4a)) was from the pollen collected at day 0 and cultured in the medium containing 5% sucrose. Moreover, the best three-factor combination for‘cv. C’ which gave the highest pollen tube length (892.08 m; data not shown) was for the pollen collected on the day 0 without the 24-h incubation and cultured in the medium containing 5% sucrose.However, all three-factor combinations gave rise to relatively short pollen tube for ‘cv. B’ (