Citrus Sunki Mandarin Budwood

Citrus reticulata.

The sunki, suenkat or sün kat of South China, which is the sour mandarin C. reticulata var. austera.

A widely employed rootstock in China and Taiwan.

A medium-small, upright tree with distinctive pale-green leaves. The fruit is medium-small, oblate and markedly depressed at both ends, and with basal furrows. The rind is very thin, loose, and light yellowish-orange, with a smooth, shiny surface and prominent oil glands. The rind is strong and spicy with a distinctive aroma. The flavor is acid, the fruit never becoming edible. Seeds are medium-large, plump, polyembryonic, and have pale-green cotyledons.

Fruits slightly depressed-globose, 2.9-3.3 cm long, 3.3-3.6 cm diam., with smooth, loose peel about 4 mm thick, capucine yellow (Ridgway, pl. 3) when ripe; oil glands small, round, far apart, fragrant; segments 9, easily separated; segment walls thin, tender, white; core 6-8 mm diam., soft; pulp deep chrom yellow (Ridgway, pl. 3), composed of small, short, pulp-vesicles, clinging together but irregularly arranged and easily broken; juice reddish yellow, very sour; seeds about 9, rounded at one end, pointed at the other, showing white parallel lines from base to tip; leaves lanceolate-elliptical, blades 6.8 X 2.5 cm, rather acutely cuneate at the base and narrowed to a blunt apex, with about 10 pairs of lateral veins; petioles nearly wingless.

This variety is widely grown about Swatow, China, where it is used as a rootstock upon which to graft the Ponkan or mi-tong-kan ("honey pot orange") and other famous varieties widely exported from Swatow.

Sunkat is tolerant of tristeza and xyloporosis but susceptible to exocortis. Sunki is reported to be susceptible to Phytophthora but has survived well in some trials. It is also said to be tolerant of blight-like diseases in Brazil. Trees propagated on Sunki are reported to be highly salt tolerant, moderately cold hardy, and only slightly susceptible to chlorosis on calcareous soils. Trees on Sunki have been reported to be smaller than standard in China and Texas but large in Florida and California. Fruit yield and quality are at least equivalent to trees on sour orange or Cleopatra mandarin. Sunki is polyembryonic but has a higher proportion of zygotic seedlings than many other rootstocks.

Rootstocks of accession: Carrizo citrange, C-35 citrange.

Prepared by the Givaudan Citrus Variety Collection at The University of California Riverside.