Saffron, the world's most expensive spice by weight, was first carried to Brazil on board Portuguese caravels, and has been a part of repertoire of spices used in traditional Brazilian cuisine ever since. Originally from central Asia, saffron (açafrão in Portuguese) was first cultivated commercially in the Eastern Mediterranean, and was part of the culinary heritage left in Portugal by the retreating Moors. It is valued around the world for the brilliant yellow color it imparts to any food to which it is added, and for its sweet, grassy or hay-like aroma and taste.
As much as this dried stigma of a crocus (that's what saffron is) is valued in Brazil, for a large portion of the country's population, its price simply puts it out of reach. By weight, saffron costs about USD $1000 per pound in most Western countries, including Brazil. So in a country in which the minimum wage is just over USD $300 per month, not many people can afford saffron.
turmeric. This spice originated in Southeast Asia and is a rhizome, like its relative, ginger. Once Brazilian kitchen slaves began to substitute this spice for true saffron, they began to refer to it as açafrão-da-terra, meaning saffron-of-the-earth, and this is the name which is most commonly used in Brazil today. As a matter of fact, it's often shortened just to açafrão under the assumption that most cooks will automatically assume that it's turmeric being spoken of, not true saffron. If a contemporary Brazilian recipe employs true saffron, the directions will make it clear not to add turmeric but rather the "high-price-spice."
Brazilian cuisine has adopted turmeric enthusiastically, and many dishes call for it to be added - I suspect not only for its color-enhancing properties, but also because of its earthy, warm taste. I've cooked Brazilian recipes which call for turmeric which, in my opinion, would not be suited to true saffron. Starting out as a cheaper substitute for a very expensive product, turmeric is now valued in Brazil for its own properties, and for its kindlier price point too.