Developing apple and pear fruitlets

Now the fruitlets have passed though fruit set they enter the early growth or cell division phase which lasts for approximately 4 to 6 weeks after full bloom (AFB), and is critical for determining the potential of the apple. Successful fertilisation of the ovules leading to seed development which triggers the swelling of the fruit flesh from the hypanthium which will form the bulk of the edible apple flesh. This is because of the production of phytohormones from the developing seeds specifically auxins and gibberellins. These hormones are essential for driving rapid cell division -mitosis in the young fruit. Hence if some of the seeds in the apple fail to form the overlying flesh is grows poorly and the fruit is wonky shaped. High auxin levels also maintain the connection to the parent plant at the abscission layer preventing early fruitlet drop. The energy demand is extremely high with high respiration rates as the fruit is actively dividing cells.

Developing Kingston Black apple fruitlets 4 weeks post fruit set at Beau Vista orchard Wairarapa NZ.