I saw the letter explaining the term "redneck" in the March 28 paper and offer another explanation that I got from one of my college professors at Mississippi State.
His explanation was that most farmers in the South plowed with a horse or mule. The normal attire of these farmers was bib overalls and no shirt (I have seen many so attired in my lifetime). The normal reins on the animal were a soft cotton plowline that ran from one end of the bit to the other in one piece and was normally looped around the neck.
Since the pulling animal was trained to respond to voice commands for left and right (gee and haw), the rein or plowline was used to stop the animal by pulling on it. The constant irritation of the soft plowline gave the user a "redneck."