(Updates prices, adds comment) Sept 28 (Reuters) - Canada’s main stock index retreated on Tuesday, as technology stocks tracked a slide in the U.S. tech-heavy Nasdaq, while a 1% drop in gold prices weighed on miners. At 9:46 a.m. ET (13:46 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 202.49 points, or 0.99%, at 20,260.93, and was on course for its worst session in over a week. Mining and technology sectors led the declines. Technology stocks fell 2.3% and were on course for their third consecutive session in losses, tracking the Nasdaq index, with the sector heavyweights coming under pressure from a surge in bond yields. Meanwhile, the materials sector, which includes precious and base metals miners and fertilizer companies, fell 1.7% as gold prices extended losses, falling 1% on a stronger dollar and U.S. Treasury yields. The two-year U.S. Treasury yield surged to 18-month highs. Canada’s benchmark stock index is still down about 1.3% so far in September after seven consecutive months of gains on concerns of a stunted global economic recovery. “What we’re seeing today is again the continuation of the big rotation from growth to value, and that’s good for Canada because it has got more energy, materials, banks and less tech,” said Gregory Taylor, portfolio manager at Purpose Investments. Further losses were limited by the energy sector, which gained 1.7% and was the only major sub-sector index in gains, as oil prices climbed for a sixth day on Tuesday boosted by a tighter supply and firm demand outlook. The financials sector, which account for about 30% of the Toronto market’s value, slipped 0.5%. HIGHLIGHTS Aurora Cannabis Inc, fell 3.7% after it missed Wall Street expectations for fourth-quarter revenue. Kirkland Lake Gold Ltd fell 8.7%, the most on the TSX, as Agnico Eagle Mines Ltd is set to buy the miner in a stock deal valued at C$13.51 billion ($10.68 billion). The TSX posted seven new 52-week highs and 14 new lows. 3253 new lows (Reporting by Amal S in Bengaluru; Editing by Krishna Chandra Eluri) Our Standards: The Thomson Reuters Trust Principles.