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EN
In the years 1964-1994 an extensive programme of wide hybridization within the Lolium-Festuca complex was carried out in Poland.Six Lolium (ryegrass) and five Festuca (fescue) species at differnt ploidy level were used for crosses.Hybrids were obtained from 72 cross combinations.This article presents a complete list of Folium-Festuca hybrids obtained in Poland in the years 1964-1994 and maintained in the collection of Institute of Plant Genetics in Poznan.The available literature concerning these hybrids is cited.
EN
Twenty field-grown genotypes of diploid Italian ryegrass (Lolium multiflorum Lam., 2n = 2x = 14) were tested for their ability to induce callus and regenerate plants. Callus cultures were initiated from segments of immature inflorescences cultured on the MS medium supplemented with 4.0 mg L-1 2,4-D. The calluses were subcultured first on the maintaining medium (MS medium with 2.0 mg L-1 2,4-D) and later on the rooting medium (MS medium with 0.2 mg L-1 2,4-D). The frequency of callus induction varied depending on the source of explant and the initial genotype. A total of 473 green plantlets were regenerated, of which 420 were established in the soil. All these plants had the morphological characteristics of Italian ryegrass. Among 372 regenerants analysed cytologically, 302 (81.2%) had the expected diploid chromosome number (2n = 2x = 14), 65 (17.5%) were tetraploid (2n = 4x = 28); several aneuploids and mixoploids were also observed. All diploid and tetraploid regenerants were male and female fertile. However, a great variation of female fertility within and between both groups of regenerants was observed.
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vol. 51
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issue 4
449-460
EN
This study focuses on the variability of chromosomal location and number of ribosomal DNA (rDNA) sites in some diploid and autotetraploid Festuca pratensis and Lolium perenne cultivars, as well as on identification of rDNA-bearing chromosomes in their triploid and tetraploid F. pratensis x L. perenne hybrids. The rDNA loci were mapped using fluorescence in situ hybridization (FISH) with 5S and 25S rDNA probes, and the origin of parental genomes was verified by genomic in situ hybridization (GISH) with L. perenne genomic DNA as a probe, and F. pratensis genomic DNA as a block. FISH detected variation in the number and chromosomal location of both 5S and 45S rDNA sites. In F. pratensis mostly additional signals of 5S rDNA loci occurred, as compared with standard F. pratensis karyotypes. Losses of 45S rDNA loci were more frequent in L. perenne cultivars and intergeneric hybrids. Comparison of the F. pratensis and L. perenne genomes approved a higher number of rDNA sites as well as variation in chromosomal rDNA location in L. perenne. A greater instability of F. pratensis-genome-like and L. perenne-genome-like chromosomes in tetraploid hybrids was revealed, indicating gains and losses of rDNA loci, respectively. Our data indicate that the rDNA loci physically mapped on chromosomes 2 and 3 in F. pratensis and on chromosome 3 in L. perenne are useful markers for these chromosomes in intergeneric Festuca x Lolium hybrids.
EN
Genomic in situ hybridisation (GISH) was used to reveal chromosome pairing in two partly fertile, triploid (2n = 3x = 21) hybrids obtained by crossing the diploid (2n = 2x = 14) Festuca pratensis Huds. (designated FpFp), used as a female parent, with the autotetraploid (2n = 4x = 28) Lolium multiflorum Lam. (designated LmLmLmLm), used as a male parent. The pattern of chromosome pairing calculated on the basis of the mean values of chromosome configurations identified in all 100 PMCs analysed, was: 0.71I Lm + 2.24I Fp + 2.18II Lm/Lm + 0.54II Lm/Fp + 4.18III Lm/Lm/Fp. A relatively high number of Lm/Lm bivalents and Fp univalents, and a low number of Lm/Fp bivalents and Lm univalents indicated that the pairing was preferential between L. multiflorum chromosomes. Other observations regarding chromosome pairing within the Lm/Lm/Fp trivalents also confirmed this preferential pairing in the analysed triploids, as the Fp chromosome was not randomly located in the chain- and frying-pan-shaped trivalents. The similarities and differences in chromosome pairing at metaphase I and the level of preferential pairing between Lolium chromosomes in the different triploid Lolium-Festuca hybrids are discussed.
EN
Abstract. Diploid and tetraploid forms of Lolium multiflorum and Festuca pratensis were crossed under controlled conditions and after embryo rescue all four combinations of autoallotriploid hybrids were obtained. Male and female fertility and chromosome pairing at metaphase I of meiosis were studied in several plants from each hybrid combination. The hybrids with two genomes of L. multiflorum and one of F. pratensis (genomic formulae LmLmFp and FpLmLm) were male and female fertile while the hybrids with two genomes of F. pratensis and one of L. multiflorum had a reduced fertility (FpFpLm) or were completely sterile (LmFpFp). Chromosome pairing at metaphase I varied among hybrid combinations depending on their genomic composition. LmLmFp and FpLmLm hybrids had similar patterns of pairing (1.83I + 5.29II + 2.85III and 2.22I + 5.22II + 2.75III, respectively) but they differed from those of FpFpLm (3.65I + 4.65II + 2.68III) and especially from LmFpFp (4.78I + 5.87II + 1.49III). Conventional analysis of meiosis failed to explain the differences in chromosome behaviour and fertility/sterility levels between the autoallotriploid hybrids with two Lolium or two Festuca genomes.
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