This is a rewrite of a post from September 2015, during the first fall harvest of my “apple orchard” (four dwarf trees).
This is apple harvest time in Minnesota, home of the Honeycrisp variety of apples, so loved by everyone who has tried one.
My honeycrisp apple trees are so loaded with apples, the branches are bending down to the ground.
It seems to be a Fall for bumper crops of all types of apples, from crabapples to honeycrisp, judging from the loaded branches of the apple trees on my street.
An apple tree loaded with fruit awaits harvest. Squirrels take one bite and spoil a perfect apple, and the deer finish them off when they fall to the ground.
Originally native to Kazakhstan, this highly productive forest tree has spread around the globe, even though the original progenitor was a small, sour, shriveled fruit that probably was more often used for a fermented beverage than eating. After all, its genus name is Malus which is Latin for “bad”, as in bad-tasting.
Quote from Michael Pollan on the origin of apples in his book, The Botany of Desire
From Kazakhstan, the seeds of better-tasting and fleshier types of apples were dropped by traders along the Silk Road to Asia and to Europe, and eventually made their way to North America with the early colonists who planted apple orchards, spreading the apple genes throughout the northeast, and eventually throughout the U.S.
Apple harvest-Kazakhstan marketplace. At its center of origin, there are 56 species of the wild Malus species, only 30 of which have been semi- or wholly domesticated for apple production.
But apples, like humans, do not produce carbon copies of themselves in their seeds, so each seed in an apple is as different from another seed in that same apple or from another seed in an apple on the same tree, as children are different from each other and from their parents. And this is where the human-apple tree mutualism becomes important in the spread of apples to every corner of the globe.
We humans perform much the same service that bees do in pollinating the apple’s flowers, by selective breeding for appealing varieties and then growing new trees of that variety from grafts merged onto hearty root stock. In return, like the nectar and pollen the tree supplies to its pollinators, the apple tree repays its dispersers (animal and human alike) with crisp, sweet fruit that lasts several months when stored properly at cool temperatures.
What is it that makes apples so delicious and so appealing to us humans?
A cross section of a Honeycrisp apple (which I ate while writing this) shows the star-shaped endocarp housing the seeds. Each of the 5 chambers houses 1-2 seeds. The total number of seeds per apple (5-10) depends on the energy resources of the tree.
Around the star-shaped seed capsules are ten yellow-green dots that are the remnants of the flower stamens. The sepals (that surround the petals of the flower) are at one end of the apple, and the flower stem (now a fruit stem) is at the other. In between is the greatly expanded floral cup that grows up and around the ovary housing the soon-to-be seeds, and is filled with starch granules synthesized by the leaves over a summer’s worth of sunlight. At the end of the summer as the skin takes on its rosy blush, those starch granules begin to break down to individual sugar molecules — and voila, sweet, juicy, crisp Fall apples are ready to be harvested.
A sample of the harvest from just one of my dwarf honeycrisp trees.
The Honeycrisp apple is an invention (!) of the University of Minnesota’s Agricultural Experiment Station Horticulture Research Center (quite a mouthful — pun intended). As an experimental variety, it was almost cast aside because the tree was not cold tolerant and couldn’t survive Minnesota winters. But the fruit was exceptionally pleasant, with large cells with stiff cell walls that stored great quantities of starch and water and a relatively thin skin that made biting into its crisp sweetness a gustatory delight. Moving a few genes around to introduce cold heartiness made the next version of the Honeycrisp a winner — to markets and palates everywhere.
Back Yard Biology 