 RNA interference has been used for applications in biotechnology and is nearing commercialization in others . RNAi has developed many novel crops such as <unk> tobacco , <unk> coffee , nutrient fortified and hypoallergenic crops . The genetically engineered Arctic apples are near close to receive US approval . The apples were produced by RNAi suppression of <unk> ( polyphenol oxidase ) gene making apple varieties that will not undergo browning after being sliced . <unk> @-@ silenced apples are unable to convert <unk> acid into quinone product . 
