Resist cultivation or have some other undesirable properties. Often low yield, short harvest, low yield, difficult picking or transporting.
A favorite example of mine: oak’s acorns are sometimes edible. Roughly one in ten oaks produce edible acorns. They are indistinguishable from inedible ones unless you try them out - but inedible ones are fairly poisonous. The gene for edible acorns is recessive and it takes at least a decade before you know if a newly planted oak produces edible acorns or not, with a 10% probability of the former. It is just practically impossible to select for this criterion. Thus, we don’t eat acorns.
Resist cultivation or have some other undesirable properties. Often low yield, short harvest, low yield, difficult picking or transporting.
A favorite example of mine: oak’s acorns are sometimes edible. Roughly one in ten oaks produce edible acorns. They are indistinguishable from inedible ones unless you try them out - but inedible ones are fairly poisonous. The gene for edible acorns is recessive and it takes at least a decade before you know if a newly planted oak produces edible acorns or not, with a 10% probability of the former. It is just practically impossible to select for this criterion. Thus, we don’t eat acorns.
And let’s not forget, low yield.