Reuters: Senior Bush Administration officials reiterated their defence of corn-based ethanol fuel on Tuesday, saying it was one factor in rising food prices but that high energy costs were the main culprit. Ethanol makers will consume about one-quarter of the 13.1-billion-bushel US corn crop this year, according to the Agriculture Department, a forecast that is increasingly alarming world governments and food aid workers. "Certainly, that is a factor as we are seeing the rising …