We examined the growth, yield, and dry matter production of rice varieties for whole-crop silage (RWCS) bred for the Tohoku region of Japan for five years from 2001 to 2005. Among the varieties newly released from the National Agricultural Research Center for Tohoku Region, earlymaturing "Ouu 395" with long culm length, as well as medium-maturing "Ouu 380", "Ouu 384", and "Ouu 387" with large grain size and high lodging registance, was selected as a RWCS showing high dry weight at the yellow-ripe stage. Among them, "Ouu 387" was selected in 2005 as a new cultivar for whole-crop silage in this region and named "Bekoaoba". Characteristics of a longer growing period and higher crop growth rate with larger leaf area before the heading stage, as well as higher crop growth rate with higher net assimilation rate during the grain filling stage, were advantageous for achieving higher dry weight at the yellow-ripe stage in the Tohoku region.