Actually when farmers do it, it's called artificial selection. I know if you want to get technical, natural & artificial selection are't proven to create new species (since the process would take a lot longer than human science has existed) but the example of the difference between the wheat of today and spelt still stands. The gene pool DOES change, you simply can't get spelt to produce wheat in a single generation when it took 10,000 years of intentional selection to make it happen.
Are you sure that spelt has less protein than modern wheat. I had the impression it was as good or higher. I know that short grained rice has a higher protein comtent than long grain rice.
A cacique is a native chief. I have used on line dictionaries to try to translate Spanish language newspaper articles. I find they only define about 1/2 the words I am looking for. May Spanish is already reasonably good, so these are the less common words. There is a dictionary by Cuyas that is like the Webster for Spanish.