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近年開発された業務・加工用向け水稲品種「あきだわら」，「やまだわら」の温暖地西部地域での品質特性を検討した．玄米外観品質に関しては，両品種 とも未熟粒の発生が多く，「日本晴」より整粒歩合が低かった．整粒歩合には総籾数や登熟気温の影響がみられ，特に「あきだわら」では，登熟期が高温となる条件での品質低下が大きい特性を持つ可能性が示された．玄米タンパク質含有率は「あきだわら」では「日本晴」並みに高い一方，「やまだわら」では「ヒノヒカリ」並みに低かった．また，「やまだ わら」では粒長が長いものの粒厚が薄いため，粒選の篩い目を大きくした場合の収量減少が多い特徴がみられた．We examined the grain appearance quality of‘Akidawara’and‘Yamadawara’, rice cultivars bred for high yield and good eating and processing quality, in the western region of Japan from 2014 to 2016. A decreased percentage of perfect grains with a larger appearance of immature grains such as white berry grains was observed in the both cultivars, compared to the standard cultivar‘Nipponbare’. From analysis of the effects on the grain quality of spikelet number and air temperature condition after heading, a possibility was suggested that‘Akidawara’is more sensitive to the high air temperature during early grain-filling periods, which promotes the decreases in the percentages of perfect grains, than cultivars‘Nipponbare’and‘Yamadawara’. ‘Yamadawara’showed the highly negative relation between the grain quality and the spikelet number. Because‘Yamadawara’had a low grain thickness, a larger loss of yield was occurred when rice grading, compared with those in‘Nipponbare’and‘Akidawara’. Protein content of grains was high in ‘Akidawara’, but it was low in‘Yamadawara’.