Improving pollination of almond (Amygdalus communis L., Rosaceae) using electrostatic techniques

Supplementary pollination of almond using electrostatic techniques was test ed in a three year study (1996-1998) in Northern Israel. We used an electro static pollination device and tested its effects on fruitlet set, fruit set , yield weight and nut weight. We also tested its ability to pollinate flow ers on the tree from the distal to the proximal part of the branches. We fo und that when individual branches were pollinated, fruitlet set was in acco rdance with the expected deposition rate of pollen grains on the stigma: el ectrostatic + open pollination > non-electrostatic + open pollination > ope n pollination > electrostatic pollination > non-electrostatic pollination > spontaneous self pollination. Fruit set results showed the same pattern bu t were not as precise. Electrostatic pollination of individual trees result ed in an insignificant increase in pollen germinability on the stigma. The highest germinability was on the distal part of the branch and the lowest w as on the proximal part of the branch, in all pollination treatments. Elect rostatic pollination increased yield as compared with non-electrostatic and open pollination. Nut weight, however, decreased slightly with increased y ield. We suggest that electrostatic pollination can be an important method for pollen supplementation in almond orchards when honeybee pollination is insufficient and when the trees can withstand the added portion of nuts, re sulting from improved pollination.