Triploid apple varieties
Most animals have two sets of chromosomes, inherited from the mother and father respectively, and are known as "diploid". This is true of many plants too, including the majority of apple varieties. However several important apple varieties have three sets of chromosomes rather than two, and are known as triploids. In effect they have three parents instead of two.
Triploid apple varieties have a couple of important characteristics which need to be considered when growing them:
- They cannot pollinate themselves (they are not self-fertile).
- Their own pollen is effectively sterile and cannot be used to pollinate other apple trees.
In short, if you are planting triploid varieties, you need to make sure you have the necessary pollinator trees nearby. You will need either one self-fertile apple variety (or crab-apple) or two other varieties which can cross-pollinate each other as well as the triploid variety.
Although the pollination requirements might be inconvenient, triploid varieties have several advantages:
- They usually produce vigorous trees, which can support large crops. The apples are often quite large.
- Triploid varieties often display a good degree of natural disease resistance.
- They can often survive in difficult conditions.
It is perhaps no co-incidence that many triploid varieties are also well known cooking apples, where large size and productivity is a useful characteristic.
Some of the best-known triploid varieties are:
- Ashmead's Kernel
- Belle de Boskoop
- Blenheim Orange
- Bramley's Seedling
- Gravenstein
- Jonagold
- Crispin / Mutsu
- Ribston Pippin
- Zabergau Reinette