When the biotech company Bayer CropScience AG requested federal permission in August to market a variety of gene-altered rice, it assured itself a small, unwanted place in history: the first to seek approval for a genetically engineered food that was already - illegally - on the market. Now, as federal regulators consider that belated application, they are finding themselves under scrutiny, too - from scientists and others who say the 20-year-old system of biotech crop oversight is failing.