Fruit trees bear fruit: apples, pears, apricots, cherries, and many others. You can find them all over the world today, as long as it’s not too cold. Fruit is very healthy because of the vitamins and should therefore be part of the daily diet.
Since ancient times, man has grown fruit trees from wild trees. These are often only distantly related in biology. Our fruit varieties were created from individual plant species through breeding. However, a distinction is not only made between the different types of fruit, but also between three main growth forms of the trees:
The standard trees mainly existed earlier. They were scattered on meadows so that the farmer could use the grass. Medium trees are more likely to be in gardens. That’s still enough to put a table underneath or to play. The most common today are low trees. They grow as a trellis on a house wall or as a spindle bush on a plantation. The lowest branches are already half a meter above the ground. So you can pick all the apples without a ladder.
How are new fruit varieties created?
Fruit comes from flowers. During reproduction, the pollen from a male flower must reach the stigma of a female flower. This is usually done by bees or other insects. If there are many trees of the same variety next to each other, the fruits will retain the characteristics of their “parents”.
If you want to breed a new type of fruit, for example, an apple variety, you have to bring the pollen from other plants onto the stigma yourself. This work is called crossing. However, the breeder must also prevent any bees from interfering with his work. So he protects the flowers with a fine net.
The new apple then brings the characteristics of both parents with it. The breeder can specifically select the parents based on the color and size of the fruit or how they tolerate certain diseases. However, he does not know what will come of it. It takes 1,000 to 10,000 attempts to create a good new apple variety.
How do you propagate fruit trees?
The new fruit bears its properties in the pips or in the stone. You could sow these seeds and grow a fruit tree from them. It is possible, but such fruit trees usually grow weakly or unevenly, or they are then again susceptible to diseases. So another trick is needed:
The grower takes a wild fruit tree and cuts the stem off a little above the ground. He cuts off a twig from the newly grown sapling, which is called “scion”. Then he places the scion on the trunk. He wraps a string or rubber band around the area and seals it with glue to keep pathogens out. This whole work is called “refining” or “grafting on”.
If everything goes right, the two parts will grow together like a broken bone. This is how a new fruit tree grows. The tree then has the properties of the grafted branch. The trunk of the wild tree is only used to provide water and nutrients. The grafting site can be seen on most trees. It is about two handsbreadths off the ground.
There are also breeders who enjoy grafting different scions onto different branches of the same tree. This creates a single tree that bears many different varieties of the same fruit. This is particularly interesting with cherries: you always have fresh cherries over a longer period of time because each branch ripens at a different time.
Only: Grafting apples onto pears or plums onto apricots is not possible. These scions do not grow, but simply die off. It’s like sewing a gorilla’s ear onto a human.