* TSX rises 48.37 points, or 0.35 percent, to 13,729.85 * Eight of 10 main index sectors advance * Potash is market's biggest positive influence * Shaw slips after quarterly report By John Tilak TORONTO, Jan 14 (Reuters) - Canada's main stock index climbed on Tuesday, firming after a decline in the previous session, as upbeat U.S. retail sales data drove up shares of materials and energy companies. However, a decline in shares of Shaw Communications Inc , following the cable company's quarterly report, capped the gains. A government report said a gauge of U.S. consumer spending rose more than expected in December, indicating greater momentum for the world's biggest economy. After recording a 9.6 percent gain last year, the Toronto market has been volatile this year. "You are getting just a little buyer's fatigue," said Matt Skipp, president of SW8 Asset Management. "If the commodity markets regain their footing and the U.S. economy truly strengthens, Canada will do very well, especially with the lower currency," he said of the TSX's prospects for 2014. The Toronto Stock Exchange's S&P/TSX composite index was up 48.37 points, or 0.35 percent, at 13,729.85. Eight of the 10 main sectors on the index were higher. The materials sector, which includes mining stocks, jumped 1.2 percent. Fertilizer company Potash Corp rose 2.5 percent to C$36.95 and had the biggest positive influence on the market. Miner Teck Resources Ltd added 2.1 percent to C$26.60. Shaw shares slipped 3.2 percent to C$24.50 after the company posted a 4 percent rise in first-quarter profit, but it continued to lose customers in its main cable television business. Shares of energy producers were up 0.2 percent, with Suncor Energy Inc gaining 0.6 percent to C$37.48.