 In the 1950s a new system known as "parral cuyano" was introduced where vines were trained high off the ground with the clusters allowed to hang down.This style was conducive to the high yielding varieties of Criolla and Cereza that were the backbone of the bulk wine production industry that arose in response to the large domestic market.In the late 20th century, as the market turned to focus more on premium wine production, more producers switched back to the traditional "espaldera" system and began to practice canopy management in order to control yields.