MADRID, April 25 - Spanish producer prices rose 0.6 percent month-on-month in March to put the yearly rate at 3.0 percent, the National Statistics Institute (INE) said on Friday. In February prices at the factory gate rose 0.6 percent month-on-month, and 2.9 percent year-on-year. The index has been calculated with 2000 as the base year since January. Up to December, 1990 was the base year.//