Apple

Apple production

"Apple Blossom" redirects here. For other uses, see Apple Blossom (disambiguation).

Apple breeding

Like most perennial fruits, apples ordinarily propagate asexually by grafting. Seedling apples are an example of "Extreme heterozygotes", in that rather than inheriting DNA from their parents to create a new apple with those characteristics, they are instead different from their parents, sometimes radically.^[20] Most new apple cultivars originate as seedlings, which either arise by chance or are bred by deliberately crossing cultivars with promising characteristics.^[21] The words 'seedling', 'pippin', and 'kernel' in the name of an apple cultivar suggest that it originated as a seedling. Apples can also form bud sports (mutations on a single branch). Some bud sports turn out to be improved strains of the parent cultivar. Some differ sufficiently from the parent tree to be considered new cultivars.^[22]

Pollination

See also: Fruit tree pollination

Apple tree in flower

Apples are self-incompatible; they must cross-pollinate to develop fruit. During the flowering each season, apple growers usually provide pollinators to carry the pollen. Honeybee hives are most commonly used. Orchard mason bees are also used as supplemental pollinators in commercial orchards. Bumble bee queens are sometimes present in orchards, but not usually in enough quantity to be significant pollinators.^[22]

There are four to seven pollination groups in apples depending on climate:

• Group A – Early flowering, May 1 to 3 in England (Gravenstein, Red Astrachan)
• Group B – May 4 to 7 (Idared, McIntosh)
• Group C – Mid-season flowering, May 8 to 11 (Granny Smith, Cox's Orange Pippin)
• Group D – Mid/Late season flowering, May 12 to 15 (Golden Delicious, Calville blanc d'hiver)
• Group E – Late flowering, May 16 to 18 (Braeburn, Reinette d'Orléans)
• Group F – May 19 to 23 (Suntan)
• Group H – May 24 to 28 (Court-Pendu Gris) (also called Court-Pendu plat)

One cultivar can be pollinated by a compatible cultivar from the same group or close (A with A, or A with B, but not A with C or D).^[25]