The citrus industry in California is changing, and growers are planting more easy-peeling, seedless, and nice-tasting mandarins. Our industry tries to develop new early- and late-season mandarin cultivars to be competitive in the global mandarin market. Seventeen satsuma mandarin (Citrus unshiu Marco.) cultivars were top-worked onto 4–6 Valencia orange [C. sinensis (L.) Osbeck] as interstocks and Carrizo citrange [C. sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.] as rootstocks in 30 May 2001 near Santa Paula, Calif. All trees set the first crop in Fall 2003. Fruit maturity of all cultivars was measured based on °Brix level, percent acid, and S:A ratio on a weekly basis since the first week of Sept. 2004. Five cultivars, `Armstrong', `Kuno Wase', `Miyagawa', `S9' and `Xie-Shan' (`Wakiyama'), are very early- or early-season cultivars. A small-scale degreening experiment with 72 h treatment of 0.5 mg·L–1 ethylene with fruit harvested on 6 Oct. 2004 also showed the rind color of all five cultivars could be enhanced nicely. `Miyagawa' had very intense internal orange flesh color visible in the second week of Sept. 2004, comparing with other cultivars. All these five cultivars could potentially become early-season, completely seedless, and easy-peeling satsuma cultivars in California. `Miyagawa' and `Xis-Shan' could potentially be harvested as early as from late September to early October in the central coastal region and from late August to mid-September in the San Joaquin Valley. Both cultivars should command a high price when there is no seedless mandarin in the market.
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