Effects of Brassinosteroid and Gibberellic Acid on In Vitro on Pollen Germination and Viability in Sweet Cherries (Prunus avium L.)

This research was carried out on 0900 Ziraat, Merton Late and Starks Gold sweet cherry trees grafted on SL64 (Prunus mahaleb) and Bing, 0900 Ziraat and Vista cultivars grafted on P. avium grown at the sweet cherry collection orchard located at Dardanos campus of Çanakkale Onsekiz Mart University, Çanakkale, Turkey. Plant growth regulators, epibrassinolide (Epi–B1) at 0.25 and 0,.50 ppm and gibberellic acid (GA3) at 25, 50 and 100 ppm concentrations were applied to the pollen germination medium. Pollen germination experiments were done with agar in the petri method and the degree of germination was calculated as the percentage from the ratio of germinated and the total number of pollen grains. Colorimetric test of Iodine potassium ıodide (IKI) were used to estimate pollen viability. Effects of the plant growth regulators on pollen germination ratios were assessed on six different rootstock–scion combinations. As a result of study, pollen germination was under the influence of both the rootstock–scion combinations and the plant growth regulators. The highest pollen germination percentages were obtained from the 0.5 ppm Epi–Bl application in five rootstock–scion combinations. The highest pollen germination (25.6%) was obtained from Bing cultivar grafted on P. avium rootstock treated with 0.5 ppm Epi–Bl. Germination ratio, on the other hand, was only affected by the hormone concentrations, and it increased significantly as the concentration was higher. Results showed that pollen viability was not under the influence of the rootstock–scion combinations. The highest pollen viability (93.4%) was obtained from Bing cultivar grafted on P. avium rootstock.