Abstract
Viable interspecific hybrids between Nicotiana repanda Willd. and N. tabacum L. are not possible by conventional hybridization but can be obtained by irradiation treatments of pollen or egg cells combined with in vitro culture of fertilized ovules. In this study cytological analyses were conducted to define chromosomal variation among viable interspecific hybrids obtained by irradiation-mediated techniques. Pollen of N. tabacum was subjected to gamma-ray irradiation dosages of 5–40 kR and used to fertilize N. repanda. Similarly, egg cells of N. repanda were treated with 1–4 kR irradiation and pollinated with N. tabacum. Chromosome number decreases in resulting interspecific hybrids were not as great as had been reported in previous studies, but exposure to higher doses of radiation induced a considerable degree of chromosomal rearrangement. Among resulting hybrids, a number reached the flowering stage. The longevity of the hybrids seemed to be correlated with their ability to generate roots (i.e., rooting vigor). Although the dosage ranges used in the egg-cell irradiation (1–4 kR) were lower than those used in the pollen irradiation (5–20 kR), the degree and quality of the chromosomal variation did not differ.Key words: wide hybridization, hybrid inviability, chromosome variation, tobacco.
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Claims 6
Claim · model-written summary
Chromosome number decreases in the interspecific hybrids were smaller than those reported in previous studies.
- Taxon
- Nicotiana repanda Willd. and N. tabacum L.
Nicotiana tabacum
Nicotiana repandat0 - Outcome
- Chromosome number decreasese1
- Comparator
- previous studiese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana repanda Willd. and N. tabacum L.”
e1“Chromosome number decreases in resulting interspecific hybrids were not as great as had been reported in previous studies”
Claim · model-written summary
Exposure to higher doses of radiation induced a considerable degree of chromosomal rearrangement in the hybrids.
- Taxon
- Nicotiana repanda Willd. and N. tabacum L.Nicotiana tabacumNicotiana repandat0
- Treatment
- higher doses of radiatione2
- Outcome
- chromosomal rearrangemente2
- Direction
- inducede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana repanda Willd. and N. tabacum L.”
e2“exposure to higher doses of radiation induced a considerable degree of chromosomal rearrangement”
Claim · model-written summary
The degree and quality of chromosomal variation did not differ between egg-cell irradiation at 1–4 kR and pollen irradiation at 5–20 kR.
- Taxon
- Nicotiana repanda Willd. and N. tabacum L.Nicotiana tabacumNicotiana repandat0
- Treatment
- egg-cell irradiation (1–4 kR)e3
- Outcome
- degree and quality of the chromosomal variatione3
- Direction
- did not differe3
- Comparator
- pollen irradiation (5–20 kR)e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana repanda Willd. and N. tabacum L.”
e3“Although the dosage ranges used in the egg-cell irradiation (1–4 kR) were lower than those used in the pollen irradiation (5–20 kR), the degree and quality of the chromosomal variation did not differ”
Claim · model-written summary
Hybrid longevity seemed to be correlated with the ability of hybrids to generate roots, i.e. rooting vigor.
- Taxon
- Nicotiana repanda Willd. and N. tabacum L.Nicotiana tabacumNicotiana repandat0
- Organ / stage
- rootse4
- Outcome
- longevity of the hybridse4
- Qualifier
- rooting vigore4
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana repanda Willd. and N. tabacum L.”
e4“The longevity of the hybrids seemed to be correlated with their ability to generate roots (i.e., rooting vigor)”
Claim · model-written summary
A number of the resulting interspecific hybrids reached the flowering stage.
- Taxon
- Nicotiana repanda Willd. and N. tabacum L.Nicotiana tabacumNicotiana repandat0
- Outcome
- reached the flowering stagee5
- Qualifier
- a numbere5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana repanda Willd. and N. tabacum L.”
e5“Among resulting hybrids, a number reached the flowering stage”
Claim · model-written summary
Viable interspecific hybrids that conventional hybridization could not produce were obtained by irradiation of pollen or egg cells with in vitro ovule culture.
- Taxon
- Nicotiana repanda Willd. and N. tabacum L.Nicotiana tabacumNicotiana repandat0
- Treatment
- irradiation treatments of pollen or egg cells combined with in vitro culture of fertilized ovulese0
- Outcome
- Viable interspecific hybridse0
- Comparator
- conventional hybridizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana repanda Willd. and N. tabacum L.”
e0“Viable interspecific hybrids between Nicotiana repanda Willd. and N. tabacum L. are not possible by conventional hybridization but can be obtained by irradiation treatments of pollen or egg cells combined with in vitro culture of fertilized ovules”
The same questions in other papers
radiation · quality: general · Nicotiana tabacum (tobacco)Positive and negative results
1 reporting no difference from an alternative
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.