scholarly journals PREFERENTIAL CHROMOSOME PAIRING IN ALLOTETRAPLOID LYCOPERSICON ESCULENTUM–SOLANUM LYCOPERSICOIDES

Genetics ◽  
1964 ◽  
Vol 50 (5) ◽  
pp. 855-862
Author(s):  
Margaret Y Menzel
Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 783-790 ◽  
Author(s):  
Roger T. Chetelat ◽  
Charles M. Rick ◽  
Joseph W. DeVerna

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.


HortScience ◽  
1990 ◽  
Vol 25 (3) ◽  
pp. 334-339 ◽  
Author(s):  
Mark A. Walker ◽  
Dale M. Smith ◽  
K. Peter Pauls ◽  
Bryan D. McKersie

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.


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

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.


Genome ◽  
2005 ◽  
Vol 48 (4) ◽  
pp. 685-697 ◽  
Author(s):  
Michael A Canady ◽  
Vladimir Meglic ◽  
Roger T Chetelat

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.


1997 ◽  
Vol 47 (4) ◽  
pp. 327-333
Author(s):  
Asako Matsumoto ◽  
Shigeru Imanishi ◽  
Monzur Hossain ◽  
Alice Escalante ◽  
Hiroaki Egashira

1986 ◽  
Vol 71 (5) ◽  
pp. 691-697 ◽  
Author(s):  
L. W. Handley ◽  
R. L. Nickels ◽  
M. W. Cameron ◽  
P. P. Moore ◽  
K. C. Sink

Genome ◽  
1998 ◽  
Vol 41 (1) ◽  
pp. 40-50 ◽  
Author(s):  
Roger T Chetelat ◽  
Charles M Rick ◽  
Pedro Cisneros ◽  
Kevin B Alpert ◽  
Joseph W DeVerna

The wild nightshade Solanum lycopersicoides possesses a number of disease- and arthropod-resistance and environmental stress tolerance traits of potential value for the cultivated tomato, Lycopersicon esculentum. F1 hybrids are readily obtained by sexual crosses, but backcrosses to tomato are hindered by sterility and incompatibility barriers. In the present studies, intergeneric sesquidiploid hybrids (2 genomes of L. esculentum and 1 of S. lycopersicoides) were pollinated with Lycopersicon pennellii derived bridging lines, yielding diploid, aneuploid (up to 2n + 6), and polyploid (3x, 4x) progeny. After diploids (58% of total progeny), the group most frequently obtained was 2n + 1 (31%), which included all 12 possible monosomic alien addition lines (MAALs) containing a single extra chromosome from S. lycopersicoides in a tomato background. MAAL groups were identified with a combination of allozyme, RFLP, and monogenic visual markers. Transmission rates of the extra chromosomes in MAALs varied from 0%, for chromosome 6, to 24%, for chromosome 10. At diakinesis and metaphase I of meiosis, the alien chromosome was usually unpaired (in an average of 90% of PMCs), but association of homoeologous chromosomes was observed in each of the 12 MAAL groups (in an average of 5.7% of PMCs). The MAALs showed a striking morphological resemblance to the corresponding tomato primary trisomic. In addition, each MAAL expressed S. lycopersicoides specific leaf, flower, and (or) fruit characters. This set of MAALs, the first of its kind in Lycopersicon, is expected to be useful for a variety of gene-mapping and introgression studies.


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