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‘Aurastar’ is a new citrus cultivar that was released in 2012 by the Okitsu Citrus Research Station, National Institute of Fruit Tree Science (presently the Division of Citrus Research, Institute of Fruit Tree and Tea Science), National Agriculture and Research Organization. ‘Aurastar’ originated from a cross between ‘H・FD−1’(an intergeneric hybrid between Citrus and Poncirus species) and cv.‘Banpeiyu’. This cross was made in 1994 in an effort to breed a variety with high resistance against citrus tristeza virus (CTV) and high auraptene content. ‘Aurastar’was registered as No.20789 under the Seed and Seedlings Law of Japan on May 24, 2012. The tree grows vigorously and is upright in growth habit. The average fruit weight is 400-450g on average and the fruit shape is oblate. The rind is yellow-orange in color, 14mm in thickness, and its peelability is difficult. The fruit surface texture is rough. The flesh is yellow in color, and at maturity (in March) the brix and acid values of the juice are approximately 11°and 2.5 g/100ml, respectively. The seeds are many and monoembryonic. The smell derived from Poncirus is almost none. The tree is resistant to citrus scab, slightly susceptible to citrus canker, and highly resistant to CTV. The flesh and peel contain high auraptene contents of 0.75 and 0.81mg/g dry weight, respectively. Since the fruit matures in middle to late March, it is desirable to cultivate it in area with relatively warm winters., ‘オーラスター’は1994年に農林水産省果樹試験場興津支場（現（国）農研機構果樹茶業研究部門カンキツ研究領域）において,カンキツ属とカラタチ属の属間雑種H・FD−1に‘晩白柚’を交配して育成された品種である.CTVに対して強い抵抗性を有し、機能性成分であるオーラプテンを果肉・果皮共に高含有するため加工用品種・育種素材として有用であると評価,選抜され,2012年5月24日付けで,種苗法に基づき,第20789号として品種登録された.‘オーラスター’の樹勢は強く,樹姿は直立性である.葉は大きく,ほとんどが三出複葉となる.果実は扁球形で育成地では概ね400～450gで平均420ｇ程度である.果皮は黄橙色,厚さは14mm程度で,剥皮性は難である.果肉は黄色で比較的柔らかく,果汁量は中程度である.クエン酸含量が高く,酸味が強い.カラタチ特有の臭気はほとんどない.そうか病には強く,かいよう病にはやや弱いと考えられている.また,CTVに対して強い抵抗性を有しており,単胚性のため,CTVに対する抵抗性品種育成のための育種親としての利用が可能である.果肉・果皮共に食用可能なカンキツ品種としては高濃度のオーラプテンを含有する. ‘オーラスター’は果実の成熟が3月中下旬となることから,冬季に温暖な地域での栽培が望ましい.

Research works on citrus tristeza virus carried out in Japan are summarized, and remained subject matters are discussed.