Electrostatic dusting: An efficient technique of pollination in larch

Abstract

Electrostatic pollination has been developed for mass production of seeds of hybrid larch (Larix x eurolepis Henry). Pollination occurs within a tank carried at the front of a tractor (fig 1). A high voltage is maintained between the pollen dispenser and the tree to be pollinated. Pollen charged with static electricity is blown on the tree by an electrostatic gun, fastened at the top of the tank. This technique favors pollen deposition on the flowers (five and 15 pollen grains per bract on the average for 0 and 40 kV, respectively) (fig 2, table II). Compared to conventional pollen blowing, electrostatic dusting enhanced full seed percentage (32 vs 23%) without reduction in seed viability although the amount of pollen used was much smaller. Moreover, this technique involves less time than the conventional method. However, seed set decreased from the top to the bottom of the crown (39 and 26% full seeds, respectively) (table III). Manual utilization of an electrostatic gun should result in good pollination, judging by the excellent seed set obtained in the branches situated near the gun (table IV).