Q: Do different types of apples have the same number of seeds? Why? We cut a Golden Delicious, Red Delicious, and a California Granny Smith apple. All three had a different number but I don’t understand why. Could you please help me out?
A: If you were to cut an apple in half, cross-sectionally, ie. not through the stem end, you would find that an apple has 5 compartments or carpels. Each of these carpels should contain a seed in order for the apple to be full sized and well shaped as the seeds produce hormones which allow the fruit to develop.
Fruit which lack seed often abort from the tree in times of stress. Varieties can have more than one seed in each carpel depending on the health and vigor of the tree; the more healthy a tree the more potential seed the fruit can have per carpel. This is probably why the different varieties had different numbers of seeds. Trees with too many fruit and seeds can exhaust the stored food of the tree and thus fail to set a crop the next year.