The news comes from Taiwan, where the delay was reportedly announced during a corporate conference at TPK. TPK has been one of the major suppliers of touch components for Apple's iPhones and iPads, and has been rumored to be a supplier for the iWatch as well. One of its subsidiaries TPK Films is one of the few companies that can build touch modules using silver nanowires, which allow components to be flexible and very small (i.e. very good for smartwatches.)
This is the second time that it has been rumored that iWatch production wouldn't start until late this year. Ming-Chi Kuo, an analyst who often gets scoops on Apple, recently said that iWatch mass production wouldn't be starting until November, which would put the release sometime in early 2015.