THE EFFECT OF TEMPERATURE ON POLLEN GERMINATION AND POLLEN TUBE GROWTH OF PEAR CULTIVARS

The effect of three different temperatures (8, 16 and 24°C) on pollen germination and length of pollen tube in vitro was investigated in four pear cultivars (‘Butirra Precoce Morettini’, ‘Williams’, ‘Conference’ and ‘Abate Fetel’). The temperature showed a significant effect on in vitro pollen germination. The highest pollen germination was determined at a temperature of 24°C (53.25%), somewhat lower at 16°C (44.72%) and the lowest at 8°C (23.16%). The temperature effect was significantly more pronounced on the length of pollen tube. Pollen tube length was about three times higher at the temperatures of 16 and 24°C compared to 8°C. The temperature of 8°C was not sufficient for pollen germination and pollen tube growth in pear cultivars. However, temperatures of 16 and 24°C were optimal for pollen germination and pollen tube growth.