Well all we know is that Turles is a low class saiyan like Bardock and Goku.
And besides if Turles was Bardock's son then he would be Goku's brother and if he was Goku's brother he would then therefore be Bardock's son or stepson or adopted son or something. Because, Bardock is Goku's daddy.
But what I crafted is that there are two breeds of saiyans that had existed on planet Saiya. The blood saiyans (Turles's breed) and the gold saiyans (Goku, Vegeta, Nappa, Raditz, Brolly, Paragus, and Bardock's breed). The difference between the Gold and Blood saiyans is that the Gold Saiyans value honor and had small traces of yellow in their hair and eyes that only a saiyan can identify. The Blood Saiyans on the other hand value deception and dishonor and had small traces of red in their hair and eyes that only a saiyan can identify.
These two breeds were at constant war with one another until a meteor struck the planet causing them in need of evacuation. The two breed put aside their differences and in a broad move the Gold saiyans deceived the Blood Saiyans and left them stranded on planet Saiya as it approached nuclear winter. The Gold Saiyans however crashed on a remote planet home to the Truffles. The Gold Saiyans took over and renamed it after their leader, Vegeta.
It's likely that the Gold Saiyans might have gotten amnesia when they crashed on the planet and thus resorted back to their primitive saiyan ways.
Nevertheless the blood saiyans were utterly wiped out except for one Saiyan that was adopted by an evil Namekian lord and was named Turles (which is probably Namekian for something).
