Citrus rootstock are plants used as

rootstock A rootstock is part of a plant, often an underground part, from which new above-ground growth can be produced. It could also be described as a stem with a well developed root system, to which a bud from another plant is grafted. It can refer to ...

for

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

plants. A rootstock plant must be compatible for scion grafting, and resistant to common threats, such as drought,

frost Frost is a thin layer of ice on a solid surface, which forms from water vapor that deposits onto a freezing surface. Frost forms when the air contains more water vapor than it can normally hold at a specific temperature. The process is simila ...

, and common citrus diseases.

Principal rootstocks

Five types of rootstock predominate in temperate climates where cold or freezing weather is not probable, especially

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

and southern

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

: * Sour orange: the only rootstock that truly is an orange (the '' Citrus'' × ''aurantium'' or bitter orange). It is vigorous and highly drought-resistant. * '' Poncirus trifoliata'': a close relative of the genus ''Citrus'', sometimes classified as ''Citrus trifoliata''. It is especially resistant to cold, the tristeza virus, and the oomycete '' Phytophthora parasitica'' (root rot), and grows well in

loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–si ...

soil. Among its disadvantages are its slow growth—it is the slowest growing rootstock—and its poor resistance to heat and drought. It is primarily used in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, and areas of

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

with heavy soils. * Swingle citrumelo: tolerant of tristeza virus and ''Phytophthora parasitica'' and moderately resistant to salt and freezing. This rootstock selection was hybridized from the Duncan

grapefruit The grapefruit (''Citrus'' × ''paradisi'') is a subtropical citrus tree known for its relatively large, sour to semi-sweet, somewhat bitter fruit. The flesh of the fruit is segmented and varies in color from pale yellow to dark red. Grapefru ...

(''Citrus paradisi Macfadyen'') and the '' Poncirus trifoliata'' (L.) Raf. by

Walter Tennyson Swingle Walter Tennyson Swingle (January 8, 1871 – January 19, 1952) was an American agricultural Botany, botanist who contributed greatly to the classification and citrus taxonomy, taxonomy of citrus. Biography Swingle was born in South Canaan, Cana ...

in Eustis, Florida, in 1907. It was released by the

US Department of Agriculture The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and producti ...

to nurserymen in 1974. * ''Troyer'' citrange and ''Carrizo'' citrange: reasonably vigorous rootstocks, resistant to ''Phytophthora parasitica'',

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

s, and tristeza virus and with good cold tolerance. They also are highly polyembryonic, so growers can obtain multiple plants from a single seed. Citrange, however, does not do well in clay,

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

or high-pH soils, and is sensitive to salinity. It is not feasible as rootstock for

mandarin Mandarin or The Mandarin may refer to: Language * Mandarin Chinese, branch of Chinese originally spoken in northern parts of the country ** Standard Chinese or Modern Standard Mandarin, the official language of China ** Taiwanese Mandarin, Stand ...

scions, as it overgrows them by producing branches of its own in competition with the grafted budwood. Citranges are hybrids of the Washington navel orange and the '' Poncirus trifoliata''. The original crosses, made in the early 1900s by the U.S. Department of Agriculture with the intention of producing cold tolerant scion varieties, were later identified as suitable for use as rootstocks. The commercial use of these rootstocks began in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

in the 1960s. The ''Troyer'' variety generally is found in California, while the ''Carrizo'' variety is used in Florida. * Cleopatra mandarin: tolerant of salinity and soil

alkalinity Alkalinity (from ) is the capacity of water to resist Freshwater acidification, acidification. It should not be confused with base (chemistry), basicity, which is an absolute measurement on the pH scale. Alkalinity is the strength of a buffer s ...

and also suitable for shallow soils. It is used primarily in

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

, and

. Dade County, for example, has 85%

soil, a typical trait of land that has been under water. The Cleopatra mandarin, originated in

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

and introduced into Florida from

Jamaica Jamaica is an island country in the Caribbean Sea and the West Indies. At , it is the third-largest island—after Cuba and Hispaniola—of the Greater Antilles and the Caribbean. Jamaica lies about south of Cuba, west of Hispaniola (the is ...

in the mid-nineteenth century, has been distributed and tested as a rootstock throughout the world. Nowadays, however, it is considered an inferior rootstock because it is sensitive to many diseases, grows slowly, and is difficult to propagate.

Other rootstock cultivars

* African shaddock X trifoliate hybridCitrus Variety Collection, University of California Riverside, College of Natural and Agricultural Sciences http://citrusvariety.ucr.edu/citrus/rootstocks.html. * Benton citrange trifoliate hybrid * Borneo Rangpur lime * Bitters C-22 citrange (''X Citroncirus sp.'' Rutaceae): it was hybridized at the

USDA The United States Department of Agriculture (USDA) is an United States federal executive departments, executive department of the Federal government of the United States, United States federal government that aims to meet the needs of commerc ...

Date and Citrus Station in

Indio, California Indio (Spanish language, Spanish for "Indian") is a city in Riverside County, California, United States, in the Coachella Valley of Southern California's Colorado Desert region. Indio is approximately east of Los Angeles, east of Palm Springs, ...

, and developed further by the

University of California, Riverside The University of California, Riverside (UCR or UC Riverside) is a public university, public Land-grant university, land-grant research university in Riverside, California, United States. It is one of the ten campuses of the University of Cali ...

. It is used primarily as rootstock for navel oranges in California. In 2009, a report suggested it also may be useful to replace sour orange rootstock for grapefruit in Texas because it is tolerant of calcareous soil.bittersC22
Citrusvariety.ucr.edu. Retrieved on 2011-10-02. Its name is not related to the bitter orange: it was named after Willard Paul Bitters, emeritus professor of Horticulture and a curator of the Citrus Variety Collection. * Carpenter C-54 citrange * C-32 citrange trifoliate hybrid * C-35 citrange trifoliate hybrid * Calamondin kumquat hybrid * Carrizo citrange trifoliate hybrid * Citradia trifoliate hybrid * Citremon trifoliate hybrid (CRC 1449) * Citrumelo trifoliate hybrid C190 * Citrumelo trifoliate hybrid (CRC 1452) * Citrumelo trifoliate hybrid (CRC 4475) * ''Citrus macrophylla'' ( Alemow) * ''Citrus volkameriana'' (Volkamer lemon) * Cleopatra mandarin X trifoliate hybrid X639 * Flying dragon trifoliate (CRC 3330A) * Fraser Seville sour orange * Furr C-57 citrange * Goutoucheng sour orange (CRC 3929) * Goutoucheng sour orange (CRC 4004) * Grapefruit seedling (CRC 343) * Pomeroy trifoliate * Rangpur lime X Troyer citrange hybrid * Rich 16-6 trifoliate * Rubidoux trifoliate * Rusk citrange trifoliate orange hybrid * Satsuma X trifoliate hybrid * Schaub rough lemon * Small-leaf trifoliate * Smooth Flat Seville sour orange * Sun Chu Sha Kat mandarin * US 119 (Grapefruit X trifoliate) X Sweet Orange hybrid * Vangassay rough lemon * Yuma Ponderosa lemon pummelo hybrid * Zhuluan sour orange hybrid (CRC 3930) * Zhuluan sour orange hybrid (CRC 3981)

Notes

References

High Quality Citrus Rootstock
by Leon Dexter Batchelor and Willard Paul Bitters
Article on new citrus rootstock
by

External links

EDIS
by

University of Florida The University of Florida (Florida or UF) is a public university, public land-grant university, land-grant research university in Gainesville, Florida, United States. It is a senior member of the State University System of Florida and a preem ...

Citrus Rootstocks
by FFSP
SunkistCompatible scion to rootstockThe Development of Improved Citrus Rootstocks
{{citrus Citrus Plant roots

Principal rootstocks

Other rootstock cultivars

See also

Notes

References

External links