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Citrus Rootstocks
Citrus is considered native to Southeast Asia. It is grown in tropical and subtropical regions between 35°N and S latitude. There is great diversity in citrus in terms of size, shape, color, and juice content. The most well known varieties are orange, lemon, grapefruit, lime, and tangerines. Asexual reproduction through grafting and budding is used to propagate superior varieties and reduce the time to fruit maturity. Different rootstocks are chosen based on traits like vigor, drought tolerance, disease resistance, and compatibility with other varieties.
Citrus Rootstocks
- 4. Citrus is consideredto be native of Southeast Asia, especially eastern India. Phylogenic relationships extends through East Indies, Australia, central China, Japan and even Africa. Many present day citrus cultivars have been cultivated since ancient times and their wild progenitors are not definitely known.
- 5. Citrus is grownin tropical and subtropical southeast regions of the world, in a belt of approximately; 35° N and S of the equator.
- 6. There is agreat diversity in citrus; size shape fruit colour juice contents The most well known examples are the orange, the lemon, the grapefruit, the lime and tangerines.
- 8. First organized programmewas started by USDA in Florida in 1893 by W.T. Swingle and H.J. Webber. Disease management (This programme was destroyed due to severe freeze in winter in 1894-95)
- 9. In 1908, USDAgroup produced large number of hybrids from many combinations of cultivars and species. ‘Troyer’, among these, is an important rootstock In University of California citrus breeding started in 1914, by H. B. Frost. University of Florida started two citrus breeding programmes in 1924 and 1956.
- 11. Kingdom Plantae Division Magnoliophyta Class Magnoliopsida Sub-class Rosidae Order Sapindales Family Rutaceae Sub-family Aurantioideae Tribe Citreae
- 12. W. T. Swingleclassified sub family Aurantioideae into a very comprehensive treatment. Citrus (16 species) Fortunella (4 specie) Poncirus (1 specie) Eremocitrus Microcitrus Citrus, Fortunella and Poncirus can be crossed with one another, and various proven hybrids exist.
- 13. Citrus aurantifolia Key Lime Citrus maxima Pomelo Citrus medica Citron Citrus reticulata Mandrin Microcitrus
- 14. Some hybrids are; Tangelo Tangerine X Grapefruit Tangor Tangerine X Orange Orangelo Orange X Grapefruit Citrange Poncirus X Sweet orange Citradia Poncirus X Sour orange Citrangequat Citrange X Kumquat
- 16. Type Shrub or small tree Height 5-15 m Growth habit Ever green Spines On twigs attachment Leaves arrangement Alternate Leaf characters Shiny, leathery, dotted Citrus tree facts and info. www.citrustreesnola.com with oil glands
- 17. Type Solitary Diameter 2-4 cm Ovary 6-14 carpel Stamens 4 X of petals Petals 4-8 (Thick, Linear) citrus sinensis. www theflowerexpert.com Flowers are very strongly scented. The vegetative apical meristem transforms into a terminal flower bud. Axillary flower bud develops later than the terminal bud.
- 18. Technical terms Usual terms Type Hesperidium berry Rind Pulp Shape Globose to elongated Zest Juice Sac Size Length= 4-30 cm Segment Diameter= 4-20 cm Mesocarp Exocarp Citrus. www.botany.com A leathery rind surrounding segments or "liths" filled with pulp vesicles.
- 20. The plant orplant part (One of the components of budding or grating) which provides root system after successful union of bud or graft with it. Citrus plants grown in the "normal" way from seedlings have several problems. Due to the complicated and in part fascinating reproductive life of citrus plants; A tree grown from a zygotic seed seldom grows true to type. Seedlings grown tree take up to 7-12 years before they grow a trunk and a root system strong enough to bear fruit.
- 21. For getting superiortrue to type plants and reducing the bearing period, asexual means of reproduction are implemented.
- 22. Different qualities candetermine the choice of rootstock; Tree vigor Rooting depth Time to reach fruit maturity Tolerance to cold and water logging Resistance to nematodes, foot rot (phytophthora), citrus blight Susceptibility to citrus tristezza, exocortis and xyloporosis viruses
- 24. Rough Lemon Kinnow mandarins Punjab Sour Orange Orange NWFP However, there are a range of different rootstocks growing at research stations and germplasm units but they have not been commercialized.
- 26. Citrus jambhiri Origin: Rough lemonoriginated in the Himalayan foothills in India.
- 27. Vigor Very vigorous Growth habit Spreading Density of branches Dense Rough lemon. Sweating Canning Growing. 2009 www. chilechews.blogspot.com
- 28. Leaf division Simple Leaf colour intensity Light Green Petiole Not winged Rough lemon. www.bugsforbugs.com.au
- 29. Advantages: Tolerant to tristeza Drought tolerant Moderate tolerance to salinity Disadvantage: Less cold hardy Intolerant to blight Susceptible to phytophthora foot rot and burrowing nematodes
- 30. Uses: Fully compatible with compatibility with oranges, grapefruit, tangelos and most mandarin varieties.
- 32. Citrus aurantium Origin: The sourorange is native to southeastern Asia. Arabs are thought to have carried it to Arabia in the 9th Century.
- 33. Vigor Vigorous Growth habit Spreading Density of branches Dense Alexandris, G. Sour orange tree. www.fotolia.com Versatile sour orange. www.fincalasbrisas.org
- 34. Leaf division Simple Leaf colour intensity Dark Petiole Winged Sour orange tree. www.bayflora.com
- 35. Advantages: Tolerant to cold Drought tolerant Resistance against gummosis Tolerate salinity and alkalinity Disadvantage: Intolerant to tristeza Susceptible to nematodes
- 36. Uses: Grapefruit and orange yields on sour orange are moderate, with average fruit size and good quality.
- 39. Citrus sinensis Origin: Sweet orangeare native to southeastern Asia, northeastern India or, more likely, southern China and Indo-China.
- 40. Vigor Medium Tree shape Spheroid Growth habit Spreading Citrus sinensis. Plante E Animali Italiani. www.digilander.libero.it
- 41. Leaf division Simple Leaf shape Elliptical Petiole Narrowly winged Citrus sinensis-Sweet orange. www.plantoftheweek.org
- 42. Advantages: Quite hardy Resistance against cold Tolerant to quick decline Disadvantage: Sensitive to soil salinity Susceptible to gummosis
- 43. Uses: Sweet orange is a good rootstock for all the citrus cultivars, producing large, vigorous trees. Yields and fruit quality produced on sweet orange stock are good and unions are compatible.
- 45. Citrus aurantium var.khatta Origin: Karna is an old Indian fruit of unknown origin, most probably native to Tropical Asia, Indo-China. Almost certainly a natural hybrid. While the tree and fruit are distinctive, they exhibit characters of both rough lemon and sour or bitter orange.
- 46. Vigor Medium Growth habit Spreading Tree habit Upright Tree shape Spheroid Kharna sour orange hybrid. www.citrusvariety.ucr.edu
- 47. Leaf division Simple Leaf colour intensity Dark Petiole Winged Jaskani, M. J. et al. 2006. Pak. J. Bot., 38(2): 311-317
- 48. Advantages: Tolerant to cold Drought tolerant Tolerate salinity and alkalinity Disadvantage: Susceptible to tristeza Susceptible to gummosis
- 49. Uses: Grapefruit and mandarins can be grown successfully on Kharna khatta.
- 51. Citrus limonia Origin: Rangpur limehas Indian origin. It is hybrid involving either the rough lemon or sour orange in the parentage.
- 52. Vigor High Tree shape Spheroid Growth habit Spreading Baishaishu Rangpur lime. www.citrusvariety.ucr.edu
- 53. Leaf division Simple Leaf shape Elliptic Petiole Obovate Rangpur. Citrus limonia www.steffenreichel.homepage.t-online.de
- 54. Advantages: Drought tolerant Tolerate salinity Highly resistant to tristeza Disadvantage: Sensitive to cold Susceptible to phytophthora Susceptible to burrowing nematodes
- 55. Uses: It makes a good union with number of citrus spp. Like sweet orange, mandarins and pummelo.
- 57. Poncirus trifoliata orCitrus trifoliata Origin: Trifoliate oranges are native to central or northern China. It is widely cultivated in temperate regions.
- 58. Vigor Medium Tree shape Ellipsoid Growth habit Spreading Trifoliate orange. www. users.kymp.net
- 59. Leaf division Trifoliate Leaf shape Ovate Petiole Obovate Poncirus trifoliata. www.plantsystematics.org
- 60. Advantages: Resistant to tristeza Tolerant to cold and water logging Resistant to phytophthora and nematodes Disadvantage: Sensitive to drought Intolerant to salinity Slow growing rootstock
- 61. Uses: It is used in high density planting as it is a dwarf rootstock. It is a good rootstock for sweet oranges, tangerines and grape fruit.
- 63. Citrus reshni Origin: Cleopatra mandarinare native to tropical Asia, Indian subcontinent.
- 64. Vigor Medium Tree shape Spheroid Growth habit Spreading Cleopatra mandarin. www.users.kymp.net
- 65. Leaf division Simple Leaf shape Elliptic Petiole Obovate Citrus reshni. www.flora-toskana.de
- 66. Advantages: Cold hardy Tolerate salinity and alkalinity Resistant to tristeza, gummosis and quick decline. Disadvantage: Sensitive to nematodes Sensitive to water logging Susceptible to phytophthora
- 67. Uses: Blood red and Valencia oranges perform well when budded on Cleopatra mandarin.
- 69. Hybrid of; Washington navel orange X Poncirus trifoliata Purpose was to combine cold hardiness of trifoliate orange with good traits of sweet orange. Origin: The original crosses were made in the early 1900s by the United States Department of Agriculture with the intention of producing cold tolerant scion cultivars.
- 70. Vigor Moderate Tree shape Ellipsoid Growth habit Spreading Density of branches Dense Oklahoma Cold Hardy Citrus Hybrid Project. www.okcitrus.com
- 71. Leaf division Simple Leaf colour intensity Dark Petiole Winged About1418 citrus. www.citrus.forumup.org
- 72. Advantages: Cold tolerant Tolerant to tristeza Tolerant to Phytophthora and nematode Disadvantage: Adversely affected by high pH Sensitive to soil salinity and water logging
- 73. Uses: Fully compatible with navel and Valencia orange varieties.
- 75. Hybrid of; Washington navel orange X Poncirus trifoliata Origin: It was originated as a hybrid of the Washington navel orange crossed with trifoliate orange pollen that was made at Riverside, California in 1909. In 1934, Swingle named it for A. M. Troyer, on whose place at Fairhope, Alabama, it first fruited.
- 76. Vigor Moderate Growth habit Spreading Density of branches Moderate Citrange, 'Troyer‘. www.woodlanders.net
- 77. Leaf size Medium Leaf division Trifoliate Leaf colour intensity Dark Citranges. www.homecitrusgrowers.co.uk
- 78. Advantages: Cold tolerant Tolerant to tristeza Tolerant to Phytophthora and nematode Disadvantage: Adversely affected by high pH Sensitive to soil salinity and water logging
- 79. Uses: Troyer citrange is the major rootstock used for mandarins.
- 81. Hybrid of; Poncirus trifoliata X Citrus sinensis Origin: The cross was made by J.W. Cameron & R.C. Baines in the Citrus Research Center, Riverside, CA, in 1951.
- 82. Vigor Medium Growth habit Spreading Tree shape Spheroid Citranges‘. www.woodlanders.net
- 83. Leaf shape Elliptic Leaf division Trifoliate Petiole shape Obovate Citranges‘. www.woodlanders.net
- 84. Advantages: Cold tolerant Drought tolerant Tolerant to tristeza Tolerant to Phytophthora and nematode Disadvantage: Sensitive to soil salinity Adversely affected by high pH
- 85. Uses: Citrange 35 is used as rootstock for navel oranges, grapefruit and valencia oranges.
- 87. W. T. Swingleclassified sub family Aurantioideae into a very comprehensive treatment. Citrus (16 species) Fortunella (4 specie) Poncirus (1 specie) Eremocitrus Microcitrus Citrus, Fortunella and Poncirus can be crossed with one another, and various proven hybrids exist.