Effects of Some Fungicides on Pollen Germination, Pollen Tube Growth and Fruit Set in Almond in- vitro and in- vivo Conditions

In order to optimize the fungicide application in almond orchards, the effects of eight different fungicides on the pollen germination, growth of pollen tubes of almond variety “Ferragness” were studied at in-vitro and in-vivo conditions. In addition, the effects of fungicides on fruit set in orchard condition were investigated. The effects of fungicide application on pollen germination and growth of pollen tubes were studied by using pollen grain culture at in-vitro condition. In order to determine fruit set percentage and treated flowers abortion after spray, two times counting of fruit set was carried out. Experiment was designed in complete randomized plan with 3 replications. Growth of pollen tubes in pistil after pollination was studied by using florescence microscope (UV). For this purpose, to check the status of pollen germination on the stigma and pollen tube penetration levels in different parts of the style, samples of flower were taken and fixed in FAA. Results showed that the fungicides affected pollen germination differently at in-vitro condition. The most pollen germination was observed in control and Sumi-eight (0/001), respectively. The least pollen germination was in Beam (0/002) and Dinocap (0/002). Results of the effects of fungicides on fruit set showed that the highest percentage of fruit set was in Sumi-eight treatment 0/001) with 44.18% and the least percentage of fruit set was in Dinocap treatment (0/002) with 27.97%. While percentage of fruit set in control was 51.72%. Results from pollen growth on the surface of stigma, 1/2 upper part of style and 1/2 lower part of style showed that, the number of germinated pollen grain on the surface of stigma with different fungicides was different, so that, in control, mean number of germinated pollen grain on the surface of stigma was 45%, at the 1/2 upper part of style was 37%, for the lower part of style was 7%, while in Sumi-eight treatment of 1 per thousand, mean number of germinated pollen grains on the surface of stigma was 37% and at the 1/2 upper part of style was 28% and lower part of style was 5%. This means that the fungicide has effect on the pollen germination in different parts of pistil.