A study on pollination of Packham's Triumph pears

The availability of pollen for fertilizing Packham's Triumph pear flowers and its dispersal aerially and by honeybees was studied in the laboratory and in a pear orchard. Ripening and dehiscence of anthers were promoted by higher temperatures and lower relative humidities. More airborne pollen was in the orchard between 10 a.m. and 4 p.m. than during the remainder of the day. Flight activity of bees was related to ambient temperature but not to visits to pear trees. Enclosing trees in beeproof cages did not cause significant effects on yield of fruit or seed counts. The apparent failure of bees to effect pollination of Packham's Triumph pear flowers is discussed.