Variation within species.. domesticated peanut and anchovy?

I suppose in the case of peanuts we have selected for the best possible agricultural product, a peanut of a certain size, not too big and not too small. This sort of selection tends to reduce the variation within the population of domesticated peanuts.

Anchovies have evolved a smaller body size due to selection pressure from nets, which allow then smaller fish through the holes. This sort of selection end to result in less variation also.