Department of Fruit Culture and Orchard Management, Dr. Y S Parmar University of Horticulture and Forestry, Nauni, Solan 173 230.
Anatomical studies of the floral buds of Delicious apple revealed that no visible signs of ovule degeneration appeared until these buds attained pink bud stage. At this stage, the process of ovule degeneration became conspicuous. Ovule degeneration further progressed with the development of floral buds until full bloom. Partial or complete degeneration of ovular components viz. integument, nucellus and funicle rendered such ovules non-functional and incapable of fertilization. The extent of ovule degeneration was influenced by weather conditions prevailing during the period of flower bud development. Sudden dropping temperature to zero or sub-zero levels by the occurrence of snow fall or hail storm or spring frost further accelerated this process and thus appears to be main contributing factors for poor fruit set.
