Citrus kharna Raf.
Citrus aurantium var. khatta
Received as seed from H.S. Gentry, USDA, Beltsville, Maryland, 1954.
Parents unknown, may be a lemon or citron hybrid. From Wandriker Farms, Poona, Maharashtra State, India.
Rootstocks of accession
Carrizo citrange, C-35 citrange
Season of ripeness at Riverside
January to March
Notes and observations
2/11/2008, RRK: From Ranjit Singh, Indigenous Citrus Germplasm in India: Citrus karna (karna-khatta, id-nimbu, jamuri, khatta nimbu, karna)...the leaves and flowers...similar to rough lemon but larger in size....
From Singh and Chadha, Genetic Resources of Citrus: Karna khatta....recognized to be a type belonging to the sour orange group... Julia F. Morton, Fruits of Warm Climates, p. 131 [http://www.hort.purdue.edu/newcrop/morton/sour_orange.html] : Among other forms of sour orange, there is in India a type called 'Karna', 'Khatta' or 'Id Nimbu', identified as C. aurantium var. khatta (or C. karna Raf.) but suspected of being a hybrid of sour orange and lemon. The fruits are typical sour oranges but the flowers are red-tinted like those of the lemon.
2/11/2008, TW & DK: Round to oblong, looks like a sour orange with a rough rind, and a nipple, said to be a lemon hybrid; thick rind. Thick rind, may be citron hybrid, but relatively tender flesh; low seed count; hyper sour, orange flesh.
Description from The Citrus Industry Vol. 1 (1967)
"Karna (Kharna Khatta, Karna Nimbu, Khatta Nimbu) [C. karna Raf.] Fruit medium to medium large, of variable form but in general round to oval; usually with broad and prominent nipple, sometimes depressed or lacking. Rind moderately thick, firm; surface smooth, warty or ribbed; tightly adherent; color golden yellow to deep orange. Segments about 11; axis medium-large and semi-hollow to solid. Flesh color dull orange; coarse-textured, only moderately juicy; flavor acid with faint aroma suggestive of sour orange. Seeds numerous, somewhat slimy, and moderately polyembryonic.
Tree vigorous, medium to large in size, upright-spreading, spiny; foliage lemon-like but darker green. New growth purple-tinted. Flowers medium-large and strongly purple-tinged. One bloom and crop per year.
Karna is an old Indian fruit of unknown origin, and almost certainly a natural hybrid. While the tree and fruit are distinctive, they exhibit characters of both rough lemon and sour or bitter orange, and there are also characters suggestive of the acid citron. The commercial importance of karna arises solely from the fact that it is extensively employed in India as a rootstock, second only to rough lemon."
Not commercially available in California.
USDA Germplasm Resources Information Network page for Kharna sour orange hybrid