scholarly journals Trunk Xylem Anatomy of Mature Healthy and Blighted Grapefruit Trees on Several Rootstocks

1994 ◽  
Vol 119 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Luiz A.B.C. Vasconcellos ◽  
William S. Castle
Keyword(s):  
Cross Sections ◽  
Citrus Tristeza Virus ◽  
Poncirus Trifoliata ◽  
Vessel Element ◽  
Sour Orange ◽  
Citrus Paradisi ◽  
Xylem Anatomy ◽  
Rough Lemon ◽  
Tristeza Virus ◽  
Cleopatra Mandarin

Wood samples were taken from healthy and blighted citrus trees on several rootstocks to describe and compare the xylem anatomy of the healthy trees and to determine if blight altered xylogenesis. Horizontal trunk xylem cores, 6 cm long, were extracted from blighted 18-year-old commercial grapefruit (Citrus paradisi Macf.) trees on rough lemon (RL) (C. jambhiri Lush.), Cleopatra mandarin (CM) (C. reshni Hort. ex Tan.), and Carrizo citrange (CC) [C. sinensis (L). Osb. × Poncirus trifoliata (L.) Raf] and from healthy trees on those rootstocks and sour orange (SO) (C. aurantium L.). Cores were taken from the eastern and western sides of the scion and rootstock of each tree. The cores were divided into 2-cm pieces and cross-sections were prepared for analysis of vessel element (VE) number and diameter in 0.5-cm increments. A sample-size study showed that tree side was not a significant source of variation and that 10 replications were sufficient to detect differences of ≈12% from the overall mean. Among the healthy trees, VE densities and diameters were similar for the trees on CC or RL and larger than those for trees on SO or CM. VEs were generally smaller and at lower densities in the scion than the rootstock. Few VE occlusions were observed in the healthy trees. In the blighted trees, to a depth of 1 cm, VE density increased and diameter decreased compared to the healthy trees. The largest change occurred in the trees on RL and in the rootstock vs. scion trunk part. The frequency of VE amorphous plugs in blighted trees ranged from 1% to 30%. Similar changes in xylem anatomy were not found in trees with citrus tristeza virus or soilborne pests. Trunk water uptake and dye movement patterns in blighted trees were typical for trees with xylem dysfunction.

Selecting disease-resistant citrus rootstocks

1993 ◽  
Vol 33 (6) ◽  
pp. 775 ◽  
Author(s):  
P Broadbent ◽  
BI Gollnow
Keyword(s):  
Citrus Tristeza Virus ◽  
United States Department ◽  
Department Of Agriculture ◽  
Collar Rot ◽  
Rangpur Lime ◽  
Citrus Breeding ◽  
Rough Lemon ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Cleopatra Mandarin

Hybrid rootstocks from a United States Department of Agriculture citrus breeding program were compared for their resistance to phytophthora collar rot (caused by Phytophthora citrophthora) and citrus tristeza virus (CTV), with 6 rootstocks used commercially in Australia. Rootstocks most resistant to collar rot were clone 22 of Poncirus trifoliara, F1 Cleopatra mandarin x English P. trifoliara, and Benton citrange. Mean lesion lengths for F1 Sunki mandarin X Mars P. trifoliata, Troyer citrange, (Rangpur lime x Swingle P. trifoliata) open pollinated, and F, Cleopatra mandarin X Christiansen P. trifoliata were not significantly different from clone 22 of P. trifoliata. Some P. trijoliata hybrids were more susceptible to collar rot than sweet orange, Cleopatra mandarin, or rough lemon. High titres of CTV in ELISA tests were evident in some hybrids, but only 1 F1 Rangpur lime X Carrizo citrange developed stem pitting symptoms. CTV titres in late spring (November) were higher in bark than in leaves.

scholarly journals Bazı Turunçgil Anaçlarında Tuza Tolerans için In vitro Testleme

2020 ◽  
Vol 8 (5) ◽  
pp. 1117-1121
Author(s):  
Mehmet Yaman ◽  
Hasan Pınar ◽  
Ubeyit Seday ◽  
Duygu Altınöz ◽  
Aydın Uzun ◽  
...  
Keyword(s):  
Poncirus Trifoliata ◽  
Sour Orange ◽  
Development Programs ◽  
Trifoliate Orange ◽  
Rough Lemon ◽  
Cultivar Development ◽  
Volkamer Lemon ◽  
Citrus Volkameriana ◽  
Cleopatra Mandarin

Just because of geographical spread, citrus species generally grow in places sensitive to salinity. Testing methods have a significant role in breeding and cultivar development programs. This study was conducted to investigate in vitro salt response of Cleopatra mandarin (Citrus reshni Tan.), sour orange (Citrus aurantium L.), rough lemon (Citrus jambhiri Lush.), Volkamer lemon (Citrus volkameriana Tan & Pasq.), Carrizo citrange (Poncirus trifoliata L. Raf. X Citrus sinensis L. Osbeck) and trifoliate orange (Poncirus trifoliata Raf.) rootstocks at different NaCl concentrations. Seeds were germinated in MS medium with 0, 45, 90 and 135 mM NaCl concentrations. In general, the greatest germination rates in all salt concentrations in Volkamer lemon and sour orange rootstocks and the lowest values were observed in rough lemon and trifoliate orange rootstocks. Present findings revealed that in vitro conditions could reliably be used in salt tolerance tests of citrus rootstocks.

OXIDATIVE ENZYME RESPONSES OF SIX CITRUS ROOTSTOCKS INFECTED WITH PHOMA TRACHEIPHILA (PETRI) KANTSCHAVELI AND GIKASHVILI

2012 ◽  
Vol 48 (4) ◽  
pp. 563-572 ◽  
Author(s):  
AYDIN UZUN ◽  
UBEYIT SEDAY ◽  
ERCAN CANIHOS ◽  
OSMAN GULSEN
Keyword(s):  
Enzyme Activity ◽  
Antioxidant Enzyme Activity ◽  
Poncirus Trifoliata ◽  
Citrus Limon ◽  
Sour Orange ◽  
Trifoliate Orange ◽  
Rough Lemon ◽  
Phoma Tracheiphila ◽  
Cleopatra Mandarin ◽  
Mal Secco

SUMMARYCitrus trees are often exposed to severe infectious diseases. Mal secco caused by Phoma tracheiphila (Petri) Kantschaveli and Gikashvili is one of the most destructive fungal diseases of lemons (Citrus limon Burm. F.). In the present study, antioxidant enzyme activity in different mal secco-resistant and susceptible citrus rootstocks including Cleopatra mandarin (C. reshni Tan.), sour orange (C. aurantium L.), rough lemon (C. jambhiri Lush.), Volkameriana (C. volkameriana Tan. and Pasq.), Carrizo citrange (Poncirus trifoliata L. Raf. X C. sinensis L. Osbeck) and trifoliate orange (P. trifoliata) was investigated. Possible differences in constitutive levels of these antioxidant enzymes and correlations between enzyme levels and mal secco caused by P. tracheiphila were examined. Among the rootstocks, Cleopatra mandarin was found to be resistant to mal secco, whereas rough lemon, sour orange and trifoliate orange were highly susceptible. Total peroxidase (TPX; EC: 1.11.1.7) activity increased in all infected rootstocks. Ascorbate peroxidase (APX; EC: 1.11.1.11) activity increased in most of the rootstocks and no correlation was found between catalase (CAT; EC: 1.11.1.6) activity and mal secco resistance. This study indicates that overall TPX activity is upregulated and APX activity is up- and down-regulated depending on the type of rootstock in response to P. tracheiphila infection.

scholarly journals Suppression of Decline-inducing Isolates of Citrus Tristeza Virus by Nondecline-inducing Isolates

HortScience ◽  
2003 ◽  
Vol 38 (1) ◽  
pp. 62-64 ◽  
Author(s):  
Charles A. Powell ◽  
Phyllis A. Rundell ◽  
Robert R. Pelosi
Keyword(s):  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
Minor Component ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sour Orange ◽  
Citrus Paradisi ◽  
Indicator Plants ◽  
Tristeza Virus ◽  
Swingle Citrumelo ◽  
Citrus Tristeza

Bark chips from six container-grown citrus trees, infected with nondecline-inducing citrus tristeza virus (CTV) isolates and maintained in a vector-free greenhouse for 10 years, 15 commercial grapefruit (Citrus paradisi Macf.) trees, and 16 commercial sweet orange [C. sinensis (L.) Osbeck] trees were used to inoculate three indicator plants each of `Madam Vinous' sweet orange [C. sinensis (L.) Osbeck], sour orange (C. aurantium L.), `Duncan' grapefruit (C. paradisi Macf.), `Mexican' lime [C. aurantifolia (Christm.)], Swingle citrumelo [C. paradisi Macf. × Poncirus trifoliota (L.) Raf.], and sour orange grafted with `Hamlin' sweet orange [C. sinensis (L.) Osbeck]. All plants providing bark chips had repeatedly tested positive by enzyme-linked immunosorbent assay (ELISA) for CTV [reacted with monoclonal antibody (MAb) 17G11], but tested negative for Florida decline-inducing isolates of CTV (did not react with MAb MCA13). After 6 months in vector-free greenhouses, all in oculated trees (except Swingle citrumelo, which is considered CTV resistant) were positive for CTV by 17G11 ELISA. In addition, some indicator plants inoculated from nine (two container, two commercial grapefruit, and five commercial orange trees) of the 37 bark chip source trees also were positive for decline-inducing CTV by MCA13 ELISA. Some of these positive indicators also showed vein-clearing symptoms characteristic of infection with a severe isolate of CTV. No control, noninoculated indicators in the same greenhouse, became infected with either decline-inducing or nondecline-inducing CTV. These results indicate that decline-inducing isolates of CTV can be present as a minor component of a mixture at levels undetectable by ELISA, and that these decline-inducing isolates can become detectable by ELISA and sometimes by symptoms when inoculated into indicator plants.

scholarly journals Eight New Somatic Hybrid Citrus Rootstocks with Potential for Improved Disease Resistance

HortScience ◽  
1992 ◽  
Vol 27 (9) ◽  
pp. 1033-1036 ◽  
Author(s):  
Eliezer S. Louzada ◽  
Jude W. Grosseti ◽  
Frederick G. Gmitter ◽  
Beatriz Nielsen ◽  
J.L. Chandler ◽  
...  
Keyword(s):  
Somatic Hybrid ◽  
Somatic Hybrids ◽  
Sweet Orange ◽  
Field Trials ◽  
Poncirus Trifoliata ◽  
Sour Orange ◽  
Rough Lemon ◽  
Hybrid Plants ◽  
Volkamer Lemon ◽  
Cleopatra Mandarin

Protoplast culture following polyethylene glycol-induced fusion resulted in the regeneration of vigorous tetraploid somatic hybrid plants from eight complementary parental rootstock combinations: Citrus reticulata Blanco (Cleopatra mandarin) + C. aurantium L. (sour orange), C. reticulata (Cleopatra mandarin) + C. jambhiri Lush (rough lemon), C. reticulata (Cleopatra mandarin) + C. volkameriana Ten. & Pasq. (Volkamer lemon), C. reticulata (Cleopatra mandarin) + C. limonia Osb. (Rang-pur), C. sinensis (L.) Osb. (Hamlin sweet orange) + C. limonia (Rangpur), C. aurantium (sour orange) + C. volkameriana (Volkamer lemon) zygotic seedling, C. auruntium hybrid (Smooth Flat Seville) + C. jambhiri (rough lemon), and C. sinensis (Valencia sweet orange) + Carrizo citrange [C. paradisi Macf. × Poncirus trifoliata (L.) Raf.]. Diploid plants were regenerated from nonfused callus-derived protoplasts of Valencia sweet orange and Smooth Flat Seville and from nonfused leaf protoplasts of sour orange, Rangpur, rough lemon, and Volkamer lemon. Regenerated plants were classified according to leaf morphology, chromosome number, and leaf isozyme profiles. All somatic hybrid plants were tetraploid (2n = 4× = 36). One autotetraploid plant of the Volkamer lemon zygotic was recovered, apparently resulting from a homokaryotic fusion. These eight new citrus somatic hybrids have been propagated and entered into field trials.

Effect of calcium sprays on the severity of internal browning in Brussels sprouts

1971 ◽  
Vol 11 (48) ◽  
pp. 123 ◽  
Author(s):  
CR Millikan ◽  
EN Bjarnason ◽  
BC Hanger
Keyword(s):  
Virus Infection ◽  
Sweet Orange ◽  
Poor Performance ◽  
Sour Orange ◽  
Brussels Sprouts ◽  
Carrizo Citrange ◽  
Rough Lemon ◽  
The Poor ◽  
Internal Browning ◽  
Cleopatra Mandarin

Five scions and ten rootstocks were tested in an eight-year trial at Irymple, near Mildura, Victoria. The scions were two old-line Lisbons, a nucellar Eureka, and two old-line Eurekas. Cumulative yields averaged for the ten rootstocks and expressed as a percentage of the best scion were : Rix Lisbon 100, Doncaster Lisbon 99, Frost Nucellar Eureka 95, Rodwell Eureka 89, and Villa Franca Eureka 73. The rootstocks, with their percentage yields in parentheses, were : Rough lemon (100), Cavanagh sweet orange (90), Symons sweet orange (84), Marsh grapefruit (73, Cox sweet orange (74), Cleopatra mandarin (72). Seville sour orange (721, Sampson tangelo (69), Emperor mandarin (69), and Carrizo citrange (30). The poor performance of Carrizo citrange is discussed in terms of virus infection and incompatibility. The incidence and importance of scion overgrowth is also reported and discussed.

scholarly journals Citrus Tristeza Virus Isolates of the Same Genotype Differ in Stem Pitting Severity in Grapefruit

Plant Disease ◽  
2020 ◽  
Vol 104 (9) ◽  
pp. 2362-2368
Author(s):  
Glynnis Cook ◽  
Beatrix Coetzee ◽  
Rachelle Bester ◽  
Johannes H. J. Breytenbach ◽  
Chanel Steyn ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Common Source ◽  
Citrus Paradisi ◽  
Full Genome ◽  
Full Genome Sequencing ◽  
Reading Frame ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Two isolates of the T68 genotype of citrus tristeza virus (CTV) were derived from a common source, GFMS12, by single aphid transmission. These isolates, named GFMS12-8 and GFMS12-1.3, induced stem pitting with differing severity in ‘Duncan’ grapefruit (Citrus × paradisi [Macfad.]). Full-genome sequencing of these isolates showed only minor nucleotide sequence differences totaling 45 polymorphisms. Numerous nucleotide changes, in relatively close proximity, were detected in the p33 open reading frame (ORF) and the leader protease domains of ORF1a. This is the first report of full-genome characterization of CTV isolates of a single genotype, derived from the same source, but showing differences in pathogenicity. The results demonstrate the development of intragenotype heterogeneity known to occur with single-stranded RNA viruses. Identification of genetic variability between isolates showing different pathogenicity will enable interrogation of specific genome regions for potential stem pitting determinants.

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