Pollen carriers in the sweet cherry, Prunus avium, in Portugal

In 1997, experiments where accomplished on the sweet cherry pollination in a DRABI orchard situated in Alcongosta, Beira Interior. Over four varieties, three experimental groups where realised on each of the six selected sweet cherry trees : first, a control group, free visited and exposed to wind and gravity. A second group, under a parallelipedic cage wich is covered with large meshes muslin. This method allows 80% of the wind to penetrate but also protect the flowers to be visited by pollinators. The third group, under a cylindrical cage, covered with closed muslin in order to inhibit almost entirely the action of the wind (only 20% penetration), permitting gravity measurements. The fruit set in the control group is superior to the caged group in the three varieties (Burlat, Geant d'Hedelfingen and Maringa) but no difference is noted in Sunburst variety. The pollinators contribution towards the 3 varieties is at least 96 to 100% and 17% in the Sunburst. The action of wind and gravity is near 0% for the 3 first varieties. Therefore, for the Sunburst this action reach 83%. Although the Sunburst is renown for its self-fertilisation, the insect pollinators bring truly benefits carrying pollen between anther and stigma in a flower. However, they are essentials for the 3 others varieties, who are self-sterile.