The cultivation variations and interrelations among quality characteristics in two-rowed, hull-less pearling barley were studied to obtain basal information for high quality production of this new class of barley in Japan. Samples of the two-rowed, hull-less cultivar “Yumesakiboshi” grown under various cultivation conditions were pearled and analyzed for the relationships between different quality characteristics. The key quality problem for two-rowed hull-less barley appeared to be the high rate of grain breakage by pearling, the rate of which positively correlated with the thousand-grain weight and negatively correlated with grain hardness. Samples with a thousand-grain weight of >40 g showed an extremely high broken-grain rate. The pearl whiteness had a negative correlation with the steely grain rate. Both the steely grain rate and the pearl whiteness showed significant correlations with grain hardness. However, the effect of grain protein content on the steely grain rate showed yearly fluctuation. The hard grain characteristics reduced the broken-grain rate, but adversely affected the steely grain rate and the pearl whiteness. The results of this study indicate that for the high quality production of two-rowed, hull-less barley, the cultivation techniques of limiting the thousand-grain weight to less than 40 g and reducing the steely grain rate are the most promising approaches.