Apple Trees: Sexual Reproduction

So this is something that I don’t think a lot of people are aware of, I myself only just recently found out when reading The Botany of Desire. Pollan is a very interesting and well written author.

ANYWAY, what I’m trying to talk about are apples. Those delicious green or red or yellow, juicy, crunchy, fantastic apples. Did you know that apples are a product of sexual reproduction? An apple can not grow without cross-pollination, a plant’s form of sex. There are a few varieties of apples that are self-fruitful (can be pollinated via pollen from their own flowers), but those trees too are often far more fruitful when cross-pollinated with pollen from another tree.
Cross-pollination will NOT occur if you plant 4 of the same variety of apple trees just because these are different individual trees. Why? Well because, due to sexual reproduction and genetic variation, all apple trees of the same variety are clones from one, yes ONE, single tree. All of the gala, or red delicious, or honey crisp apple trees IN THE WORLD are derived as graphs from their one single original tree.

Think about it…you are genetically different from both of your parents. Certainly, you share some similar traits: eye color, hair color, health factors; but you are NOT a genetic match to your parents, OR your siblings. This is because humans are products of sexual reproduction, or the mixing of genes. Apples reproduce the same way. Cross-pollination allows fruit to grow, and although that fruit will be of the same variety as the parent tree it grows on, the seeds inside of that fruit will possess a very different genetic makeup than that of its parent tree. An apple is simply the ovary of the plant, a vessel for carrying the reproductive unit – the seeds. Cross-pollination does not affect the fruit of the parent tree because apples are a part of the reproductive system, not an outcome of reproduction – as ovaries are part of the human reproductive system and eggs become the outcome of reproduction when fertilized – forming a fetus.

So, while you might have the most BEAUTIFUL golden delicious tree in your back yard, producing juicy, sweet fruit, the seeds inside those golden delicious apples are FAR from similar to the parent plant. Your golden delicious could be cross-pollinated with any number of different species of apple trees. Your neighbor might have some sort of crab apple, or a red delicious, or a crop of cider apples. Any or ALL of these trees likely had some part to play in the cross-pollination of your golden delicious apples, producing seeds that are vastly genetically different than the parent plant from which the apple grew.

Simply put, planting apple trees from seed and expecting a fantastic honey crisp to just pop-up is naive, and frankly it won’t happen. Because all honey crisp trees are grafts of a parent tree, they are all genetically identical – one honey crisp can not successfully cross-pollinate another. What you will more than likely end up with is a crab or cider apple tree. Sure, you’ll get apples, however the likelihood of them being delicious and palatable is slim to none.

Apples are the result of YEARS of trial and error, and for most growers, luck. Apple orchards were originally planted to produce apples for cider and vinegar. These orchards were planted and grown from apple seeds, not grafts, so all of the trees in each orchard were genetically diverse. This genetic diversity meant that the trees were more immune to blight, insects, and disease. Although the apples may not have tasted great, the trees were hearty and strong. Every once in a while, a grower would notice one of the trees in her orchard would look quite different, or possess a different quality that allowed it to stand out from its companions. Most of these differences involved a fruit that was much more palatable and delicious than the others. Other differences included size, shape, color, and of course, taste. When a grower would come across this unique tree, the grafting would begin, and there was money to be made.

There are hundreds of varieties of apples in the world today, however, because all apples of the same variety are clones of the parent tree, apple trees have sacrificed heartiness and immunity for good tasting, desirable fruit. In my opinion, if you’re wanting to plant an orchard of apple trees, do try and grow some from seed. Your best bet is to take seeds from your absolute favorite varieties (mine being honey crisp and granny smith), sprout and plant them. Once your seed-trees have established themselves (after about a year) and are looking strong, then go ahead and plant your clone varieties. So let’s say I’m planning a small orchard of 6 trees, I’m going to plant one granny smith, one honey crisp, and four of my seed-trees. Why? The genetic diversity of seed trees will help prevent pests and blight in your clone trees. The cross pollination of your seed-trees to your clone trees will produce fruit AND new seeds that have (in theory) a 3/4 genetic makeup of your ideal clone plant. It’s all a cycle, you can continue to plant seed-trees from your clone trees in an effort to concentrate genetics and potentially come to a fruit that is similar to your favorite, though does not have the propensity for weakness and disease. It’ll take a good long while, but you could also end up creating the next new delicious variety of apple, all in your back yard!

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