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L. M. McMurphy A. L. Rayburn 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1992,84(7-8):798-802
Summary C-band number, guard cell length, and chloroplast number per guard cell were determined for eight maize populations. These populations consisted of maize selected for cold tolerance at the University of Nebraska as well as the original unselected populations. The genome size of these populations had previously been determined. C-band number fluctuated concertedly with the changes in genome size indicating that deletions and additions of constitutive heterochromatin occurred during selection, resulting in altered genome sizes. Guard cell size of all the cold tolerant populations was greater than the cell size of the respective nonselected populations. Chloroplast number per guard cell was also higher in all the cold tolerant populations than in their parental populations, but the increases were not statistically significant. The results indicate that changes in genome size that occurred during selection for cold tolerance are the result of changes in amounts of C-band heterochromatin and that the selection process results in an increase in cell size in the cold tolerant populations. 相似文献
3.
B. Friebe M. C. Cermeño F. J. Zeller 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,73(3):337-342
Summary C-banding patterns and nucleolar activity were analyzed in Dasypyrum villosum, its added chromosomes to hexaploid wheat and the hexaploid amphiploid Triticum dicoccum-D. villosum. Two different populations of the allogamous species D. villosum (2n= 14, VV) from Greece and Italy were analyzed showing a similar polymorphism for C-banding pattern. Six of the seven addition lines were identified by their characteristic C-banding pattern. No polymorphism between both members of each added alien chromosome was found. Furthermore, nucleolar activity and competition were studied by using silver staining procedure. In D. villosum only one chromosome pair, A, was found to be responsible for organizing nucleoli. The results obtained in the amphiploid and in the addition lines demonstrate that nucleolar activity is restricted to SAT-chromosomes 1B and 6B of wheat, while those of D. villosum remain inactive. 相似文献
4.
Transfer of the 1BL/1RS wheat-rye-translocation from hexaploid bread wheat to tetraploid durum wheat
B. Friebe F. J. Zeller R. Kunzmann 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,74(4):423-425
Summary The present study describes a cytological stable alien chromosome translocation in tetraploid durum wheat. By crossing the hexaploid 1BL/1RS wheat-rye translocation line Veery to the tetraploid durum wheat cultivar Cando it was possible to select a 28 chromosomic strain homozygous for the 1BL/1RS translocation. The disease resistance potential of the short arm of rye chromosome 1R, which has been widely introduced in many hexaploid bread wheat cultivars could be now also used for the improvement of durum wheat. 相似文献
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Roland von Bothmer Maija Kotimäki Ib Linde-Laursen 《Plant Systematics and Evolution》1987,156(3-4):183-188
Hybrids between the Chinese endemic speciesPsathyrostachys huashanica
Keng and the SW. Asian speciesP. fragilis (Boiss.)Nevski (all 2n = 14) developed normally but were completely sterile. Meiotic analyses revealed a high chiasma frequency indicating that the two species as well asP. juncea (Fisch.)Nevski share the same basic genome (called N). The hybrid nature of the plants was established through karyotype analysis and Giemsa C-banding. 相似文献
7.
S. E. Ashmore A. S. Shapcott 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,78(2):249-259
Summary Investigations have been carried out on karyotype change in both callus and suspension cell cultures of Haplopappus gracilis (2n=4). It has been found that polyploidization arises directly in culture to give up to six times the normal diploid chromosome number in some cultures. In polyploid cultures, both chromosome loss and chromosome rearrangements occur to give rise to aneuploid karyotypes displaying chromosomes which differ in morphology from the diploid set. Whole or partial chromosome loss has been observed in the form of lagging chromosomes and chromosome bridges at anaphase, and micronuclei, ring chromosomes and chromosome fragments at other stages in mitosis. C-banded preparations have confirmed the occurrence of chromosomal rearrangements. Comparative investigations suggest that (i) more polyploidy occurs in callus cultures than in suspension cell cultures, and (ii) the presence of cytokinin (kinetin) in the culture medium may reduce the extent of karyotype change. 相似文献
8.
Marcelo dos Santos Guerra Maria Tereza M. Nogueira 《Plant Systematics and Evolution》1990,170(3-4):229-236
Analysis of several populations in a large part of the distribution area of the genusEmilia in Brazil has revealed only two species: the diploidE. sonchifolia and the tetraploidE. fosbergii. The more widely reportedE. coccinea was not found. They show a karyotype constancy in morphology and chromosome number (2n = 10 and 2n = 20, respectively), C-banding pattern and number of secondary constrictions. Some indications were found thatE. fosbergii may be an allopolyploid and that its ancestors had different genome sizes. 相似文献
9.
E. M. Watson 《Plant Systematics and Evolution》1988,159(1-2):1-17
Chromosome C-band patterns have been studied in 34 populations of the Australian annualBulbine group, which comprises 4x (2n = 26, 28), 8x (2n = 52, 54) and 12x (2n = 78) populations. The 2n = 26B. semibarbata populations have a simple, low heterochromatin pattern with very minor polytypic variation. The 2n = 28 populations, corresponding morphologically to a group given separate status asB. alata, are similar in pattern but exhibit pronounced enhancement of telomeric and, more particularly, centromeric dot bands. NOR heterochromatin and satellites are difficult to identify inB. alata but appear to occur in different positions from the 26-chromosome karyotype. Eastern Australian 8 x patterns are consistent with a proposed hybrid ancestry,B. semibarbata ×B. alata. Annual and perennial C-band profiles in the AustralianBulbine are discussed briefly in relation to the additive and transformation models of heterochromatin evolution and to the possible adaptive significance of variation in heterochromatin content.Cytoevolution in the AustralianBulbine 2; for part 1 see Pl. Syst. Evol.157, 201–217. 相似文献
10.
Crepis dinarica andC. froelichiana are two closely related species of theC. praemorsa complex. Even though they exhibit the same chromosome number (2n = 8) and similar idiogram shape, they differ widely in quantity and distribution of heterochromatin bands. The hybrids between these two species comprise three morphological types. Parental genomes were distinguished in hybrids by Giemsa differential staining (C-banding). Although meiosis presents only a few abnormalities (about 2.4%), the percentage of aborted pollen grains is very high (90%). 相似文献