US Wheat futures stumble again, ending lower on broad commodity pressure and ample world supplies. A stronger dollar and worries about Europe's economy weigh on commodities generally, and wheat in particular has had added pressure from Thursday's USDA report, which showed world stockpiles climbing to record highs. That mitigates any concerns about a potential decline in exports from the Black Sea. CBOT March Wheat ends down 16c to $6.30/bushel, KCBT March falls 19c to $6.73 and MGEX March slides 17 1/2c to $8.14 1/4.