Apples, sexual and asexual reproduction

	Many varieties of apples exist, and there are categories such as eating (dessert) apples, cooking apples, as well as cider apples. See if you can name some apple varieties: > crab apples, Cox's, Granny Smith, Bramley, golden delicious, discovery, gala etc	Apples are classified by botanists as pomes :"accessory fruits". The part which is eaten is produced from the end of the flower stalk - "the floral cup". The inner section - the core, containing pips (seeds) - is actually the true fruit.
	Although apples are fruits and they contain seeds, new apple trees are not normally produced by growing on from seeds. In fact apple varieties are usually propagated by transferring buds or shoots from established varieties onto other trees which are not allowed to produce their own fruit. This is called grafting, and the fruiting variety is called the scion. The other variety of apple is called the rootstock. Often the rootstock influences the growth of the tree above. There are some varieties (dwarfing rootstocks) which cause the tree to remain at a manageable height for easy picking rather than growing into a large tree where ladders are required.

Not all apples are edible; crab apples are extremely sour, but can be turned into crab apple jelly when cooked with lots of sugar. Crab apples grow wild in lots of places, but they have been cultivated for the beauty of the trees in flower. Crab apples are probably the original source from which cultivated apple varieties have been developed, and are sometimes used to provide rootstock.

Pollination and fertilisation

Apples will not develop on an apple tree unless the tree is pollinated. This is normally carried out by bees or bumble bees, not by wind as in some crops. Bees visit the flowers (apple blossom) in order to collect the sugary liquid nectar, and pollen from the male parts (stamens, consisting of anthers held up by filaments) attaches to their body by accident. When they visit other flowers, some of this pollen rubs off onto the stigma, the receptive surface of the female parts. If the pollen is of the correct variety, it will grow a tube down the style and into the ovary where it releases a pair of nuclei, one of which fuses with the nucleus of the ovule (female cell). This is fertilisation. In fact bees will clean off some of the pollen that sticks to their body, collect it into "pollen baskets" on their hind legs and take it back to the hive to be stored and eaten. It is said to contain protein. Some apple varieties need to receive pollen from another variety (cross-pollination), although some can be self-pollinated. If there is not an appropriate variety in the area, fewer apples will be produced. Why do fruit growers place bee hives on the edges of their orchards? > To ensure pollination of flowers by bees, to maximise fruit production > (secondary reason) to get honey which will have a distinctive flavour from the fruit tree blossom Why do fruit growers sometimes plant a few trees of different apple varieties on the edge of their orchards? > As a pollen source - to ensure cross-pollination of flowers to maximise fruit production Why are bees more important as pollinators than other insects? > They have bristles on their body which catch pollen > They systematically visit the same sort/species of flowers so they will pollinate more effectively

	In about 1825 Richard Cox planted two seeds from a Ribston Pippin which he is thought to have pollinated with a Blenheim Orange. Some years later, when the trees had fruited, he realised they had potential. These were later to be known as the Cox's Orange Pippin and Cox's Pomona. In 1836 he supplied some grafts to a local nurseryman who sold the first trees in 1840. The varieties remained nationally unknown until Charles Turner of the Royal Nurseries, Slough, started to promote them in 1850. The original Cox's Orange Pippin tree is thought to have blown down in a gale in 1911, but two sixty year old trees were seen still standing in the garden in 1933, presumably direct grafts from the original.	Are apple seedlings the result of sexual or asexual reproduction? > sexual - there are both male and female parts in the flower, and a male nucleus from pollen must fuse with a female nucleus in the ovule
	These apples come from two varieties which are thought to be the parents of the original Cox's Orange Pippin.

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