Embryo Sac Development in Sour Cherry During the Pollination Period as Related to Fruit Set

The development of the embryo sac was followed during the pollination period in ‘Montmorency’ sour cherry ( Prunus cerasus L.) and related to fruit set. Twenty five percent to 40% of the embryo sacs were incomplete, degenerating, or contained four nuclei or fewer at anthesis and were considered nonfunctional. The effective pollination period extended for 3 to 5 days in each of two growing seasons, and fruit set ranged from 14% to 26%. The incidence of nonfunctional ovules at anthesis did not appear to be sufficient to fully account for the limited fruit set observed. Other factors, most likely physiological, play a contributing role.