GRAINS-Wheat hovers around 3-week low on plentiful supply CANBERRA, Nov 1 (Reuters) - Chicago wheat prices fell on Wednesday to match Tuesday's three-week low on strong supplies from Russia, lacklustre demand and less concern about small crops in southern hemisphere exporters. Soybeans also slipped while corn edged higher. Most-active wheat futures on the Chicago Board of Trade (CBOT) Wv1 were down 0.2% at $5.55 a bushel by 0418 GMT, their fourth straight daily fall. Prices rose in October due to fears that dry weather would further reduce yields in Argentina and Australia, but rain has fallen in both countries. Wheat is now nearing September's three-year low of $5.40. "Current prices are low enough to encourage demand for U.S. wheat," said Ole Houe at Australian agricultural brokerage IKON Commodities, adding that this should support prices. But upside is also limited for the time being because cheap supply from the Black Sea remains plentiful, he said. "Longer term, wheat is well sup