In Guns, Germs and Steel, why did almonds prove to be more domesticable while acorns did not?

The chapter you need to look at to answer this question is
the one intriguingly entitled "How to make an Almond." This fascinating chapter
discusses the way that different foods were able to be domesticated and why, and then
also looks at the many other kinds of foods that were not able to be domesticated. Even
though Native Americans used acorns extensively in the eastern United States, acorns
have never been domesticated in the same way as almonds have, when both are naturally
bitter. This is for three main reasons:

1) Oak trees grow
very slowly, compared to an almond tree that grows in three or four years. An acorn
needs about a decade.

2) Squirrels eat most of the acorns
from oak trees. It is difficult for humans to gain access to a wide range of acorns to
selects the ones they want to use.

3) Finally, the
bitterness in almonds is controlled by one single gene. In oak trees, the bitterness is
controlled by many genes. Note the logical conclusion that this would
have:

If
ancient farmers planted almonds or acorns from the occasional nonbitter mutant tree, the
laws of genetics dictate that half of the nuts from the resulting tree growing up would
also be nonbitter in the case of almonds, but almost all would still be bitter in the
case of oaks. That alone would kill the enthusiasm of any would-be acorn father who had
defeated the squirrels and remained
patient.

So we can see that
oak trees and almond trees are very different in lots of ways, regarding the time it
takes for them to grow, the way that squirrels consume the majority of acorns, and then
finally the genetic story behind their bitterness. This meant that it was a lot easier
for almonds to be domesticated whereas oak trees have not been
domesticated.