Isozyme analysis, chromosome pairing, and fertility of Lycopersicon esculentum × Solanum lycopersicoides diploid backcross hybrids

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 783-790 ◽  
Author(s):  
Roger T. Chetelat ◽  
Charles M. Rick ◽  
Joseph W. DeVerna
Keyword(s):  
Lycopersicon Esculentum ◽  
Chromosome Pairing ◽  
Linkage Mapping ◽  
Intergeneric Hybridization ◽  
Morphological Markers ◽  
Stainable Pollen ◽  
Mendelian Segregation ◽  
Solanum Lycopersicoides ◽  
Novel Traits ◽  
Backcross Hybrids

The wild nightshade Solanum lycopersicoides possesses potentially valuable traits for tomato (Lycopersicon esculentum) improvement. Male sterility of the intergenic F1 hybrid and its stylar rejection of tomato pollen have until recently prevented introgression. In the work herein described, ovule fertility was detected in the F1 hybrid following pollinations with S. lycopersicoides. Pollinations of the F1 with L. pennellii derived bridging hybrids resulted in a BC1 population of 65 plants. BC2 seed was obtained from most BC1 individuals. Male fertility of the BC1 plants ranged from 0 to 66% acetocarmine-stainable pollen. Of the 43 plants scored, 41 were diploids (2n = 24) and 2 were aneuploids (2n = 25 and 2n = 26). Chromosome pairing of the BC1 at diakinesis and metaphase I averaged 11.1 bivalents per pollen mother cell. BC1 and BC2 plants were scored for 19 isozyme and morphological markers covering 10 of the 12 S. lycopersicoides chromosomes. Significant deviations from Mendelian segregation were observed for seven loci, with an excess of homozygotes (+/+) in all cases. Wa, which controls the white anther trait of S. lycopersicoides, was mapped to within 15 centiMorgans (cM) of Got-4, while Mdh-4 was closely linked to Pgi-1 (<2 cM). Plants heterozygous for the S. lycopersicoides allele (+/s) at Dia-2, Skdh-1, Wa, and Aco-1 showed significantly lower pollen stainability than homozygotes (+/+). Skdh-1 and Got-3 heterozygotes had less chromosome pairing at meiosis than homozygotes. These hybrids will permit the introgression of novel traits from S. lycopersicoides into tomato.Key words: tomato, segregation, linkage mapping, quantitative trait loci, intergeneric hybridization.

scholarly journals A Chlorophyll Fluorescence Screening Test to Evaluate Chilling Tolerance in Tomato

HortScience ◽  
1990 ◽  
Vol 25 (3) ◽  
pp. 334-339 ◽  
Author(s):  
Mark A. Walker ◽  
Dale M. Smith ◽  
K. Peter Pauls ◽  
Bryan D. McKersie
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
Lycopersicon Esculentum ◽  
Temperature Stress ◽  
Low Temperatures ◽  
Screening Test ◽  
Full Range ◽  
Chilling Tolerance ◽  
Solanum Lycopersicoides ◽  
Commercial Cultivars

The chilling tolerance of commercial Lycopersicon esculentum cultivars (H2653, H722), Solanum lycopersicoides, an F1 hybrid of S. lycopersicoides × Sub-Arctic Maxi, and 25 BC2F2 lines of L. hirsutum × H722 (backcrossed twice to H722) was evaluated using a chlorophyll fluorescence assay. The ratio of the initial to the peak fluorescence (Fo: Fp) measured from fully expanded leaves was chosen as an indicator of plant health. Chilling induced an increase in Fo: Fp that was correlated with the sensitivity of the plant to low-temperature stress. Values of Fo: Fp remained low for cold-treated S. lycopersicoides and the F1 hybrid, which showed few symptoms of chilling-related damage, whereas the commercial cultivars, which were essentially intolerant to low temperatures, had large increases in Fo: Fp. A full range of Fo: Fp values was measured in the 25 BC2F2 lines, indicating that some chilling tolerance from the L. hirsutum parent was expressed by plants in these populations.

Chromosome pairing and potential for intergeneric recombination in some hypotetraploid somatic hybrids of Lycopersicon esculentum (+) Solanum tuberosum

Genome ◽  
1993 ◽  
Vol 36 (6) ◽  
pp. 1032-1041 ◽  
Author(s):  
J. H. de Jong ◽  
A. M. A. Wolters ◽  
J. M. Kok ◽  
H. Verhaar ◽  
J. van Eden
Keyword(s):  
Solanum Tuberosum ◽  
Lycopersicon Esculentum ◽  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Somatic Hybrids ◽  
Cytogenetic Study ◽  
Unreduced Gametes ◽  
Root Tip ◽  
Prophase I ◽  
Metaphase I

Three somatic hybrids resulting from protoplast fusions of a diploid kanamycin-resistant line of tomato (Lycopersicon esculentum) and a dihaploid hygromycin-resistant transformant of a monohaploid potato (Solanum tuberosum) line were used for a cytogenetic study on chromosome pairing and meiotic recombination. Chromosome counts in root-tip meristem cells revealed two hypotetraploids with chromosome complements of 2n = 46 and one with 2n = 47. Electron microscope analyses of synaptonemal complex spreads of hypotonically burst protoplasts at mid prophase I showed abundant exchanges of pairing partners in multivalents involving as many as eight chromosomes. In the cells at late pachytene recombination nodules were found in multivalents on both sides of pairing partner exchanges, indicating recombination at both homologous and homoeologous sites. Light microscope observations of pollen mother cells at late diakinesis and metaphase I also revealed multivalents, though their occurrence in low frequencies betrays the reduction of multivalent number and complexity. Precocious separation of half bivalents at metaphase I and lagging of univalents at anaphase I were observed frequently. Bridges, which may result from an apparent inversion loop found in the synaptonemal complexes of a mid prophase I nucleus, were also quite common at anaphase I, though the expected accompanying fragments could be detected in only a few cells. Most striking were the high frequencies of first division restitution in preparations at metaphase II/anaphase II, giving rise to unreduced gametes. In spite of the expected high numbers of balanced haploid and diploid gametes, male fertility, as revealed by pollen staining, was found to be negligible.Key words: synaptonemal complex, recombination, chromosome pairing, somatic hybrid, Lycopersicon esculentum (+) Solanum tuberosum.

A library of Solanum lycopersicoides introgression lines in cultivated tomato

Genome ◽  
2005 ◽  
Vol 48 (4) ◽  
pp. 685-697 ◽  
Author(s):  
Michael A Canady ◽  
Vladimir Meglic ◽  
Roger T Chetelat
Keyword(s):  
Lycopersicon Esculentum ◽  
Segregation Distortion ◽  
Germ Line ◽  
Introgression Lines ◽  
Primary Group ◽  
Solanum Lycopersicoides ◽  
Minimum Number ◽  
Map Resolution ◽  
Strong Segregation ◽  
Chromosome Segments

A set of introgression lines (ILs), containing individual chromosome segments from the wild nightshade Solanum lycopersicoides bred into the genetic background of cultivated tomato (Lycopersicon esculentum), has been developed. A primary group of 56 lines was selected for maximum representation of the S. lycopersicoides genome (~96% of the total map units), homozygosity, and a minimum number of introgressed segments per line. A secondary set of 34 lines provides increased map resolution in certain regions. Approximately 34% of the lines were sterile in the homozygous condition, but could be maintained by heterozygotes. To facilitate identification of segregating ILs, restriction fragment length polymorphism probes were converted to higher throughput cleaved amplified polymorphic sequence markers, which supplement allozyme and morphological loci. Strong segregation distortion was observed in F2 progeny of heterozygous ILs, with an excess of L. esculentum alleles in most regions. For introgressions on distal chromosome 1L, a preferential transmission of S. lycopersicoides alleles was observed in the male germ line. Homozygous ILs generally yielded less seed from self pollination than corresponding heterozygotes, indicating that sterility effects were recessive. This IL library provides a novel resource for genetic studies of traits found in S. lycopersicoides.Key words: Lycopersicon esculentum, Solanum lycopersicum, Solanum lycopersicoides, segregation distortion, alien introgression.

scholarly journals POLYMORPHISMS, LINKAGE AND MAPPING OF FOUR ENZYME LOCI IN THE FISH GENUS XIPHOPHORUS (POECILIIDAE)

Genetics ◽  
1979 ◽  
Vol 93 (4) ◽  
pp. 947-960
Author(s):  
Donald C Morizot ◽  
Michael J Siciliano
Keyword(s):  
Linkage Group ◽  
Mapping Function ◽  
Mendelian Segregation ◽  
Electrophoretic Variants ◽  
F1 Hybrid ◽  
Electrophoretic Patterns ◽  
Enzyme Loci ◽  
Group I ◽  
Backcross Hybrids ◽  
O 19

ABSTRACT Electrophoretic variants at four additional enzyme loci—two esterases (Est-2, Est-3), retinal lactate dehydrogenase (LDH-1) and mannose phosphate isomerase (MPI)-among three species and four subspecies of fish of the genus Xiphophorus were observed. Electrophoretic patterns in F1 hybrid heterozygotes confirmed the monomeric structures of MPI and the esterases and the tetrametric structure of LDH in these fishes. Variant alleles of all four loci displayed normal Mendelian segregation in backcross and F2 hybrids. Recombination data from backcross hybrids mapped with Haldane's mapping function indicate the four loci to be linked as Est-2—0.43—Est-3—0.26—LDH-1—O.19—MPI. Significant interference was detected and apparently concentrated in the Est-3 to MPI region. No significant sex-specific differences in recombination were observed. This group (designated linkage group 11) was shown to assort independently from the three loci of linkage group I (adenosine deaminase, glucose-6phosphate dehydrogenase, and 6-phospho-gluconate dehydrogenase) and from glyceraldehyde-3-phosphate dehydrogenase and two isocitrate dehydrogenase loci. Evidence for conservation of the linkage group, at least in part, in other vertebrate species is presented.

scholarly journals Backcross Hybrids of Zinnia angustifolia and Z. violacea: Embryology, Morphology, and Fertility

1996 ◽  
Vol 121 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Thomas H. Boyle
Keyword(s):  
Morphological Characters ◽  
Stainable Pollen ◽  
Breeding Lines ◽  
Bedding Plants ◽  
Commercial Potential ◽  
True Breeding ◽  
Backcross Hybrids ◽  
Zinnia Angustifolia ◽  
Ray Florets ◽  
Parental Lines

True-breeding lines of Zinnia marylandica Spooner, Stimart and Boyle [allotetraploids of Z. angustifolia H.B.K. and Z. violacea Cav. (2n = 46)] were reciprocally backcrossed with diploid and autotetraploid forms of Z. angustifolia (2n =22 or 44) and Z. violacea (2n =24 or 48). In most cases, backcrosses were more successful with Z. angustifolia and Z. violacea as autotetraploids than as diploids. Seed-generated, backcross (BC1) families were obtained by crossing Z. marylandica (as female) with autotetraploid Z. angustifolia or autotetraploid Z. violacea. BC1 plants were phenotypically intermediate between the two parental lines for most morphological characters. Crosses between Z. marylandica and autotetraploid Z. angustifolia yielded BC1 plants with 33% stainable pollen, whereas crosses between Z. marylandica and autotetraploid Z. violacea yielded BC1 plants that produced malformed, poorly-stained pollen. No embryos were observed in capitula collected from field-grown BC1 plants. BC1 hybrids of Z. marylandica and autotetraploid Z. violacea produced larger capitula and more ray florets than Z. marylandica, and exhibited novel combinations of floral pigments not observed in Z. marylandica ray florets. BC1 hybrids of Z. marylandica and Z. violacea have commercial potential as seed-propagated, bedding plants.

scholarly journals Fertile Somatic Hybrids between F1(Lycopersicon esculentum*L. peruvianum var. humifusum) and Solanum lycopersicoides.

1997 ◽  
Vol 47 (4) ◽  
pp. 327-333
Author(s):  
Asako Matsumoto ◽  
Shigeru Imanishi ◽  
Monzur Hossain ◽  
Alice Escalante ◽  
Hiroaki Egashira
Keyword(s):  
Lycopersicon Esculentum ◽  
Somatic Hybrids ◽  
Solanum Lycopersicoides

Sibling species of the blackfly Prosimulium onychodactylum (Simuliidae, Diptera): a salivary gland chromosome study

1983 ◽  
Vol 61 (12) ◽  
pp. 2816-2835 ◽  
Author(s):  
Lester J. Newman
Keyword(s):  
Salivary Gland ◽  
Reproductive Isolation ◽  
Sibling Species ◽  
Chromosome Pairing ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Homologous Pairing ◽  
Chromosome Markers ◽  
Chromosome Arm ◽  
Backcross Hybrids

Larvae of the morphospecies Prosimulium onychodactylum collected from two streams in northern Oregon are divided into 11 sibling species based on fixed and polymorphic inversions. The sibling species have differentiated sex chromosomes; each sibling species falls into one of two groups based on the chromosome arm which carries the sex chromosome markers. Males exhibit lack of homologous pairing or inversion heterzygosity and females have complete chromosome pairing or inversion homozygosity. There is a succession of sibling species which mature in the streams from January through September. Mature larvae of each sibling species are present for about 6 weeks; some are synchronic while others are allochronic. Some of the sibling species occur in the same stream and others are in different streams. Sibling species which are both synchronic and sympatric appear to be reproductively isolated. Reproductive isolation may not be complete for sibling species which are normally allopatric or allochronic; small numbers of F1 and backcross hybrids were found between some of these sibling species. The division of the morphospecies into sibling species was also observed in collections from Washington through northern California.

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