well, Becase of climate,rice grow in south China while wheat grow in north China,in south China,rice is the stable food ,and in north China,people prefer food made of flour.Oringinally,Chinese had no idea about bread,even now we just eat it as snack.But we have some kinds of food similar to bread(only in my opinion),we call that "man tou"(it has nothing to do with "man").Man tou is also made of flour ,but people steam it instead of toast it.