* Canadian dollar at C$1.2237 or 81.72 U.S. cents * Bond prices mostly lower across the maturity curve TORONTO, April 22 (Reuters) - The Canadian dollar strengthened against its U.S. counterpart on Wednesday, as the prices of crude oil, a key Canadian export, edged higher, underpinned by a softer dolar. With little domestic economic news on tap this week, the loonie will remain sidelined, with moves driven largely by the U.S. dollar and U.S. crude prices. * At 9:22 a.m. EDT (1322 GMT), the Canadian dollar was trading at C$1.2237 to the greenback, or 81.72 U.S. cents, stronger than the Bank of Canada's official close of C$1.2281, or 81.43 U.S. cents on Monday. * The currency's strongest level of the session was C$1.2208 Its weakest level was C$1.2287. * U.S. existing home sales data for March is due at 10:00 a.m. EDT. * U.S. crude prices were up 0.1 percent to $56.66, while Brent crude added 0.8 percent to $62.59. * The Canadian dollar, which was outperforming most of its key currency counterparts except the Australian dollar and the British pound, will likely trade between C$1.2215 and C$1.2305 against the U.S. dollar on Wednesday, according to National Bank Financial Group. * Canadian government bond prices were mostly lower across the maturity curve, with the two-year price down 1.5 Canadian cents to yield 0.653 percent and the benchmark 10-year falling 25 Canadian cents to yield 1.469 percent. * The Canada-U.S. two-year bond spread was 12.1 basis points, while the 10-year spread was -45.4. (Reporting by Solarina Ho)