I have a question for any evolutionary biologists out there.

You could do it within a single generation, provided you are allowed to make the program as stringent as you wanted it to be: just prevent anyone under 88 or so inches from breeding.

0 generations. Find someone with the required height. Neuter everyone else.

>>8573199
*Kill everyone else

>>8573179
this guy gets it

>>8573075
>let's say
>let's say
Let's not say, let's use data.
> universal breeding program
fgt pls

>>8573075
depends on how many people you find, which genes you need to amplify are they recessive or dominant, is it even a gene you are looking for or something else, etc. to be able to calculate an expected number of generations where noone under 90 inches would be born, if you only use breeding that is - which will potentially be very slow, especially since control over womb effects will be very difficult
if you use genetic engineering and you know your genes then 1 generations, because you'd just take any ol' genome and put the genes you want in there, insert into a womb/woman you know and have studied how her genes affect the fetus precisely