Abstract

The fertilization biology of eight sweet cherry cultivars (0900 Ziraat, Lambert, Sunburst, Lapins, Starks Gold, Bing, Chelan and Summit) was studied. Pollen viability was determined with triphenyl tetrazolium chloride (TTC) and fluorescein diacetate (FDA) tests. Pollen germination tests were carried out by hanging drop method on 0, 5, 10, 15 and 20% sucrose solutions. Pollen quantity and pollen morpholo-gical homogeny were determined by hemocytometry method. Pollen tube growth and fruit set ratios of open-pollinated and self-pollinated flowers were also explored. Using TTC and FDA tests, the highest pollen viability rate was obtained with cultivar Sunburst; however, higher pollen germination ratios were obtained with cultivar Lapins and Bing. Starks Gold and Summit cultivars produced more amount of pollen than the other cultivars. A high pollen morphological homogeny was found for all the cultivars. In self, cross and open pollinations, pollen tubes reached the ovules in 2 to 5 days. The pollen tubes of the self pollinated self-fertile cultivars reached the ovule in a less time. Fruit set ratios of the cross-pollinated combinations varied between 0 and 40%. In comparison with self-incompatible cultivars, fruit set ratios of self-fertile cultivars were higher.

Key words: Sweet cherry, pollination, pollen tube growth, fruit set.