How have the plants themselves changed since domestication?

Question

How have the plants themselves changed since domestication?

Answer 1

For the most part either they or their seeds or fruits have gotten bigger - corn is a prime example of this.  Another example are berries - look at a wild blueberries size versus the size of the ones you find in the supermarket.

Answer 2

In general the edible part of the plant becomes larger and easier to get to and the seeds become easier to access or release.  You can still find wild varieties of many fruits that we eat that are much smaller and perhaps slightly "dis"-colored than the ones you buy in the store.  Strawberries are a great example.

Answer 3

Sometimes fruit size and sweetness increases, sometimes it becomes more tender (carrots), sometime it loses it's bitterness and toxicity (almonds), usually it gives higher yields, sometimes it becomes easier to harvest (domesticated barley loses the "shattering" mechanism whereby wild barley drops all the seeds to the ground).

Frequently this is done by increasing the ploidy level.  Ploidy refers to how many copies of the genes the plant keeps.  Human are diploid, meaning we have two copies.  Sperm and eggs are both haploid meaning they only have one, so when two come together, they become diploid, producing a human.

Corn is tetraploid, having four.  Some crops have as many as 12.