A new Italian ryegrass (Lolium multiflorum Lam.) early cultivar ‘Quattro-TK5’ was recently bred at the Tohoku Agricultural Research Center, NARO. ‘Quattro-TK5’ showed higher yields than ‘Waseaoba’ in snow-covered areas along the Pacific Ocean. However, it is not clear whether ‘Quattro-TK5’ returns higher yields than ‘Waseaoba’ in snow-covered areas along the Sea of Japan, because the quality and quantity of snow vary between the Sea of Japan side and Pacific sides. In this research, we investigated the yield performance of ‘Quattro-TK5’ in areas along the Sea of Japan. ‘Quattro-TK5’ showed higher yields than ‘Waseaoba’ in areas with long durations of snow cover-the prefectures Yamagata, Niigata, and Iwate. In Akita, Toyama, and Ishikawa prefectures, where snow cover duration is not as long, ‘Quattro-TK5’ showed as much yield as ‘Waseaoba’. ‘Quattro-TK5’ is expected to grow in areas with up to 80 days of continuous snow cover.
