scholarly journals Production of Tetraploid Somatic Hybrid Breeding Parents for Use in Lemon Cultivar Improvement

HortScience ◽  
1992 ◽  
Vol 27 (5) ◽  
pp. 445-447 ◽  
Author(s):  
N. Tusa ◽  
J.W. Grosser ◽  
F.G. Gmitter ◽  
E.S. Louzada

Allotetraploid somatic hybrid plants of `Hamlin' sweet orange (Citrus sinensis L. Osbeck) + `Femminello' lemon (C. limon L. Burm. f.), and Milam lemon (purported hybrid of C. jambhiri Lush) + `Femminello' lemon were regenerated via somatic embryogenesis following protoplast fusion. `Hamlin' and Milam protoplasts were isolated from undeveloped ovule-derived embryogenic callus cultures and fused using a polyethylene glycol method with seedling leaf-derived protoplasts of `Femminello' lemon. Somatic hybrids were identified on the basis of leaf morphology, root-tip cell chromosome number, and electrophoretic analyses of phosphoglucose isomerase, phosphoglucose mutase, and 6-phosphogluconate dehydrogenase leaf isozymes. The somatic hybrids will be used in interploid crosses with lemon in an effort to generate seedless triploid lemon types with improved tolerance to mal secco disease.

HortScience ◽  
1992 ◽  
Vol 27 (10) ◽  
pp. 1125-1127 ◽  
Author(s):  
Jude W. Grosser ◽  
Frederick G. Gmitter ◽  
E.S. Louzada ◽  
J.L. Chandler

Allotetraploid somatic hybrid plants of `Nova' tangelo [a sexual hybrid of `Clementine mandarin (C. reticulata Blanco) × `Orlando' tangelo (C. reticulata × C. paradisi Macf.)] + `Succari' sweet orange (C. sinensis L. Osbeck), and `Hamlin' sweet orange (C. sinensis L. Osbeck) + `Dancy' tangerine (C. reticulata) were regenerated following protoplast fusion. `Nova' and `Hamlin' protoplasts were isolated from ovule-derived embryogenic callus and suspension cultures, respectively, and fused using a polyethylene glycol method with seedling leaf-derived protoplasts of `Succari' and `Dancy', respectively. Plants were regenerated via somatic embryogenesis, and somatic hybrids were identified on the basis of leaf morphology, root-tip cell chromosome number, and electrophoretic analysis of peroxidase and phosphoglucose mutase isozyme banding patterns. Diploid plants were regenerated from unfused protoplasts of `Hamlin', `Nova', and `Succari'. Tetraploid plants of `Hamlin' and `Succari' were also recovered, apparently resulting from homokaryotic fusions. No `Dancy' plants were recovered. The somatic hybrid and autotetraploid plants can be used for interploid hybridization with selected monoembryonic scions to generate improved seedless triploid tangor/tangelo cultivars. The lack of suitable tetraploid breeding parents has previously inhibited the development of quality seedless cultivars by this method.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 482f-482
Author(s):  
Francisco A. A. Mourão Fo ◽  
Jude W. Grosser ◽  
Frederick G. Gmitter

Protoplast culture following polyethylene glycol (PEG)-induced fusion resulted in the regeneration of somatic hybrid plants from the following combinations: `Succari' sweet orange (C. sinensis L. Osbeck) + `Ponkan' mandarin (C. reticulata Blanco), `Succari' sweet orange + `Dancy' mandarin (C. reticulata), `Succari' sweet orange + `Page' tangelo [a sexual hybrid between `Minneola' tangelo (C. reticulata × C. paradisi Mcf.) × `Clementine' mandarin (C. reticulata)], `Valencia' sweet orange (C. sinensis) + `Page' tangelo. `Succari' and `Valencia' protoplasts were isolated -from ovule-derived embryogenic cell suspension cultures and from seedling leaves for the other parents. Somatic hybrid plants were Identified on the basis of leaf morphology and electrophoretic analysis of isozyme banding patterns. Root tip cell chromosome counting is being performed on all plants. Other putative somatic hybrids Include: `Succari' sweet orange + `Minneola' tangelo; `Succari' sweet orange + `Murcott' tangos (C. sinensis × C. reticulata); `Valencia' sweet orange + `Murcott' tangor; and `Valencia' sweet orange + `Dancy' mandarin. These plants may have direct cultivar potential, but there primary use will be for interploid hybridization with selected monoembryonic scions to produce improved seedless triploids.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 482g-483
Author(s):  
Francisco A. A. Mourão Fo ◽  
Jude W. Grosser ◽  
Frederick G. Gmitter

Protoplast culture following polyethylene glycol (PEG)-induced fusion resulted in the regeneration of somatic hybrid plants from the following combinations: `Succari' sweet orange (C. sinensis L. Osbeck) + Severinia disticha; `Hamlin' sweet orange (C. sinensisj + S. disticha: `Valencia' sweet orange (C. sinesis) + S. disticha; `Nova' tangelo (C. reticulata hybrid) + S. disticha; `Succari' sweet orange + S. buxifolia; `Nova' tangelo + Citropsis gilletiana; and `Succari' sweet orange + Atlantia ceylanica. `Succari', `Hamlin', `Valencia', and `Nova' protoplasts were Isolated from ovule-derived embryogenic callus and/or suspension cultures whereas protoplasts of S. disticha, S. buxifolia, C. gilletiana, and A. ceylanica were isolated from leaves of potted trees in a greenhouse. Plants were regenerated via somatic embryogenesis and somatic hybrids were identified on the basis of leaf morphology. Electrophoretic analysis of isozyme banding patterns and root tip chromosome counts are being performed. Somatic hybrids with S. disticha are apparently weak whereas the other somatic hybrid plants with S. buxifolia, C. gilletiana, and A. ceylanica exhibit adequate vigor. These are more examples that the the techique of protoplast fusion can be an important tool in overcoming barriers to hybridization of sexually incompatible species.


2000 ◽  
Vol 23 (3) ◽  
pp. 661-665 ◽  
Author(s):  
Fernanda Januzzi Mendes-da-Glória ◽  
Francisco de Assis Alves Mourão Filho ◽  
Luis Eduardo Aranha Camargo ◽  
Beatriz Madalena Januzzi Mendes

Protoplast culture following polyethylene glycol-induced fusion resulted in the regeneration of somatic hybrid plants between Caipira sweet orange (Citrus sinensis L. Osbeck) and Rangpur lime (C. limonia L. Osbeck). The plants were confirmed as somatic hybrids by leaf morphology, chromosome number and RAPD profile. All regenerated plants were tetraploid (2n = 4x = 36), with intermediate leaf morphology and complementary RAPD banding profile of both parents. This combination may be useful as a rootstock for the citrus industry in Southeastern Brazil since this somatic hybrid could combine the drought tolerance and vigor of Rangpur lime with the blight tolerance of Caipira sweet orange.


HortScience ◽  
1992 ◽  
Vol 27 (9) ◽  
pp. 1033-1036 ◽  
Author(s):  
Eliezer S. Louzada ◽  
Jude W. Grosseti ◽  
Frederick G. Gmitter ◽  
Beatriz Nielsen ◽  
J.L. Chandler ◽  
...  

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.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1155d-1155
Author(s):  
Jinq-Tian Ling ◽  
N. Nito ◽  
M. Iwamasa

Protoplasts were isolated from embryogenic calli of Citrus reticulata cv. Ponkan and Citropsis gabunensis, and fused in electric fields. The maximal fusion efficiency was obtained by application of AC at 75 V/cm (1.0 MHz) and DC square-wave pulse at 1.125 KV/cm for 40 usec. Fusion-treated protoplasts were cultured on MT medium without phytohormone, solidified with 0.6% agar. Colonies from the protoplasts were proliferated on MT medium with zeatin 1 mg/l and 0.9% agar. Selection of somatic hybrid callus was based on chromosome count and isoenzyme analysis. The somatic hybrids were tetraploid (2n=36). C. reticulata and C. gabunensis were both homozygous at Got-1 locus, but distinguishable easily because band of the latter migrated faster than that of the former. In zymogram of somatic hybrid, both parent bands were retained and a new hybrid band was also evident between them. Embryos from somatic-hybrid callus regenerated intact plant. The hybrid plants showed intermediate morphological characteristics of the parents.


HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Victor Medina-Urrutia ◽  
Karla Fabiola ◽  
Lopez Madera ◽  
Patricia Serrano ◽  
G. Ananthakrishnan ◽  
...  

No presently available rootstock combines all the available rootstock attributes necessary for efficient long-term citriculture (production and harvesting) of Mexican limes and other commercially important scions. In the present study, somatic hybridization techniques were used to combine the widely adapted Amblycarpa mandarin (also known as Nasnaran mandarin) with six different trifoliate/trifoliate hybrid selections: Benton, Carrizo, and C-35 citranges; Flying Dragon and Rubidoux trifoliate oranges; and a somatic hybrid of sour orange + Flying Dragon. The ultimate goal of this research is to generate polyploid somatic hybrids that express the complementary horticultural and disease resistance attributes of the corresponding parents, and have direct potential as improved tree-size controlling rootstocks. Somatic hybrids from all six parental combinations were confirmed by a combination of leaf morphology, flow cytometry, and randomly amplified polymorphic DNA (RAPD) (for nuclear hybridity) and cleaved amplified polymorphic sequence (CAPS) analyses (for mtDNA and cpDNA). This is the first report of citrus somatic hybridization using Amblycarpa mandarin. Unexpected hexaploid somatic hybrid plants were recovered from the fusion of Amblycarpa mandarin + C-35 citrange. Hexaploid hybrids should be very dwarfing and may have potential for producing potted ornamental citrus. Resulting somatic hybrid plants from all six combinations have been propagated by tissue culture and/or rooted cuttings and are being prepared for commercial field evaluation for their potential as improved rootstocks for Mexican lime and other important scions.


1990 ◽  
Vol 115 (6) ◽  
pp. 1043-1046 ◽  
Author(s):  
N. Tusa ◽  
J.W. Grosser ◽  
F.G. Gmitter

Protoplasm culture following the chemical fusion of `Valencia' sweet orange [Citrus sinensis (L.) Osb.] protoplasts, isolated from an embryogenic suspension culture, with `Femminello' lemon [Citrus limon (L.) Burro. f.] leaf protoplasts resulted in the regeneration of an interspecific allotetraploid somatic hybrid plant, two autotetraploid lemon plants, and diploid plants from both parents. The regeneration of plants from lemon leaf protoplasts is an example of protoplast-to-plant regeneration from non-nucellus-derived tissue for Citrus. Regenerated plants were classified according to leaf morphology, chromosome number, and analyses of phosphohexose isomerase (PHI), peroxidase (PER), and 6-phosphoglucose dehydrogenase (PGD) zymograms. The somatic hybrid plant was vigorous, with leaves morphologically intermediate to the parents. The tetraploid lemon plants were similar to diploids, although less vigorous and with thicker leaves. The tetraploid lemon and somatic hybrid plants, if fertile, could be used in interploid sexual crosses to breed triploid seedless lemon cultivars with tolerance of mal secco disease from sweet orange. Further investigation of plant regeneration from leaf protoplasts could increase the number of totipotent Citrus clones amenable to somatic hybridization and genetic transformation experiments.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 462a-462
Author(s):  
Alexander A.T. Johnson ◽  
Richard E. Veilleux

Somatic hybrid plants were obtained through protoplast fusion of monoploid potato. Of three separate fusions, two were interspecific between Solanum phureja and S. chacoense, whereas one was intraspecific between two S. phureja clones. Microsatellites, or SSRs, were employed to distinguish true somatic hybrids from somaclones of unfused protoplasts. Primers flanking eight different SSR loci obtained from GenBank accessions for potato were developed for PCR amplification. Microsatellites consisted of di-, tri-, and tetra-nucleotide repeat units that varied from 4 to 20 repeats per locus. The majority of microsatellites were highly polymorphic between the S. phureja and S. chacoense clones and the presence of both parental alleles in fusion regenerants indicated their interspecific hybrid nature. One interspecifc somatic hybrid could be identified at three of the four examined loci (two tri- and one di-nucleotide repeat loci). The parents were monomorphic at the remaining di-nucleotide repeat, thereby rendering it unsuitable for hybrid identification. A similar result was obtained for another interspecific hybrid, with four of five loci appearing polymorphic between the parents and in the somatic hybrid. Less polymorphism was observed between the parents of an intraspecific S. phureja somatic hybrid, with only one locus (a tetra-nucleotide repeat) of five examined showing polymorphism. Results indicate that SSRs are a consistent and reliable means for somatic hybrid identification in potato. In order to reduce the cost and time of maintaining numerous calluses through a lengthy tissue culture regeneration phase, a technique was developed to screen calluses prior to regeneration. Using SSRs and a rapid DNA extraction method, hybrid and nonhybrid calluses could be distinguished rapidly without adversely affecting subsequent regeneration of shoots from the callus.


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