VARIATION IN THE TRANSMISSION OF UNIVALENT CHROMOSOMES FROM PENTAPLOID WHEAT HYBRIDS

1968 ◽  
Vol 10 (4) ◽  
pp. 908-912 ◽  
Author(s):  
F. H. Alston ◽  
J. K. Jones

Univalent transmission was studied in aneuploids from pentaploid (AABBD) wheat hybrids. Two groups of such hybrids were used: one group carried heterozygous AABB chromosome complements derived from crosses between T. aestivum cv. Chinese Spring monosomics XV-XXI and T. durum, cvs. Nursi and Samara, 2n = 28; the second group had homozygous AABB complements and came from crosses between the amphiploid (T. durum cv. Carleton × Aegilops squarrosa) and T. durum cv. Carleton. The transmission of univalent D chromosomes was markedly reduced when most of the AABB chromosome complement was derived from T. durum.

Genetics ◽  
1981 ◽  
Vol 97 (2) ◽  
pp. 391-414
Author(s):  
Jan Dvořák ◽  
Patrick E McGuire

ABSTRACT Wheat cultivar Chinese Spring (Triticum aestivum L. em. Thell.) was crossed with cultivars Hope, Cheyenne and Timstein. In all three hybrids, the frequencies of pollen mother cells (PMCs) with univalents at metaphase I (MI) were higher than those in the parental cultivars. No multivalents were observed in the hybrids, indicating that the cultivars do not differ by translocations. Thirty-one Chinese Spring telosomic lines were then crossed with substitution lines in which single chromosomes of the three cultivars were substituted for their Chinese Spring homologues. The telosomic lines were also crossed with Chinese Spring. Data were collected on the frequencies (% of PMCs) of pairing of the telesomes with their homologues at MI and the regularity of pairing of the remaining 20 pairs of Chinese Spring chromosomes in the monotelodisomics obtained from these crosses. The reduced MI pairing in the intercultivar hybrids was caused primarily by chromosome differentiation, rather than by specific genes. Because the differentiation involved a large part of the chromosome complement in each hybrid, it was concluded that it could not be caused by structural changes such as inversions or translocations. In each case, the differentiation appeared to be unevenly distributed among the three wheat genomes. It is proposed that the same kind of differentiation, although of greater magnitude, differentiates homoeologous chromosomes and is responsible, together with structural differentiation, for poor chromosome pairing in interspecific hybrids.


Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1063-1067 ◽  
Author(s):  
D. A. Laurie

Wheat × pearl millet crosses were studied to determine whether fertilization occurred and whether any resulting hybrids were karyotypically stable. Crosses between the hexaploid wheat genotype 'Chinese Spring' (kr1, kr2) and the pearl millet genotype 'Tift 23BE' gave fertilization in 28.6% of the 220 florets pollinated. Chromosome counts from zygotes at metaphase confirmed the hybrid origin of the embryos. Three had the expected F1 combination of 21 wheat and 7 pearl millet chromosomes and a fourth had 21 wheat and 14 pearl millet chromosomes. The expected F1 chromosome complement was also found in a primary endosperm mitosis. The hybrid embryos were karyotypically unstable and probably lost all the pearl millet chromosomes in the first four cell division cycles. Similar results were obtained using two other wheat genotypes. Crosses between the hexaploid wheat genotype 'Highbury', which differs from 'Chinese Spring' in having alleles for reduced crossability with rye and Hordeum bulbosum at the Kr1 and Kr2 loci, and 'Tift 23BE' gave fertilization in 32% of analyzed florets. This was not significantly different from the frequency found in 'Chinese Spring', indicating that 'Tift 23BE' was insensitive to the action of the Kr genes. Crosses between the tetraploid wheat genotype 'Kubanka' and 'Tift 23BE' gave fertilization in 48% of florets. The potential of pearl millet for wheat haploid production is discussed.Key words: wheat, pearl millet, wide hybridization, chromosome elimination.


1982 ◽  
Vol 24 (5) ◽  
pp. 575-582 ◽  
Author(s):  
George Fedak

Hordeum vulgare cultivars Betzes, Bonus, and Emir were crossed with Triticum aestivum cultivars Chinese Spring and Koga. Variable cultivar effects on chiasma frequency in hybrids were observed. Chiasma frequencies per cell varied from 0.38 in the Emir × Chinese Spring hybrid to 3.27 in the Bonus × Koga hybrid. Paired configurations involved homeologous wheat chromsomes.


1980 ◽  
Vol 22 (1) ◽  
pp. 117-123 ◽  
Author(s):  
George Fedak

The intercrossing of wheat (Triticum aestivum L. cv. Chinese Spring) and barley (Hordeum vulgare L. cv. Betzes) yielded hybrids at a frequency of 0.80% of pollinated florets for the barley-wheat combinations and 0.23% for the reciprocal cross. An increase in homoeologous pairing of wheat chromosomes was observed in both hybrids compared with the pairing observed in wheat haploids indicating that the barley genome had pairing promoting properties. Cytological abnormalities such as hyperploid meiotic cells and isochromosomes were attributed to abnormalities at premeiotic mitosis.


1986 ◽  
Vol 28 (2) ◽  
pp. 240-246 ◽  
Author(s):  
C. Ceoloni ◽  
I. Strauss ◽  
M. Feldman

While an extra dose of chromosome 2A of common wheat, previously reported to carry a pairing promoter on its short arm, did not increase pairing between homoeologous chromosomes in F1 hybrids between common wheat cv. Chinese Spring (CS) and Aegilops variabilis, two doses of chromosome 2D or 2B caused a significant increase in homoeologous pairing. Evidently, chromosomes 2D and 2B carry a pairing promoter(s). Studies of F1 hybrids between aneuploids of CS, either deficient for chromosome 2D or having it in an extra dose, and Ae. variabilis, Ae. longissima, and Secale cereale supported the finding that this chromosome carries a pairing promoter. Using ditelosomic lines, the promoter was found to be located on the short arm of 2D (2DS). It was deduced that the promoter of 2B is also located on the homoeologous short arm, i.e., on 2BS. Evidence was obtained that the long arm of 2D may carry a suppressor(s) of pairing. Thus, the short arm of 2A, 2D, and 2B carries a pairing promoter(s), while the long arm of 2D and possibly of 2A and 2B carry a minor suppressor(s). The promoters are more potent than the suppressors and the overall effect of group-2 chromosomes is pairing promotion.Key words: wheat, homoeologous pairing, pairing promoter, pairing suppressor, intergeneric hybrid, meiosis.


1980 ◽  
Vol 22 (3) ◽  
pp. 381-389 ◽  
Author(s):  
J. Dvořák ◽  
D. R. Knott

Two homoeologous-recombination-produced gene transfer lines in which leaf rust resistance genes from Triticum speltoides Tausch were incorporated into the chromosome complement of Triticum aestivum L. emend. Thell. were analyzed. One line, F-7-3, originated from the cross T. aestivum cv. Neepawa × T. speltoides accession F and the other line, E-11-14, originated from the cross T. aestivum cv. Manitou × T. speltoides accession E. The lines were crossed with Chinese Spring monosomics. Segregation of the F2 progenies from monosomic F1's indicated that both genes were on chromosome 1B. The lines were then crossed with Chinese Spring ditelosomics 1BS and 1BL and the F1, plants were testcrossed to Manitou. Meiotic chromosome pairing in the F1 plants and the segregation of the telosomes and resistance in the testcrosses provided evidence that both gene transfers involved chromosome arm 1BL. The exchange points showed 41% and 4% recombination with the centromere in F-7-3 and E-11-14, respectively. Recombination between the transferred alien chromatin and the chromatin of the recipient wheat chromosome is either severely reduced or entirely absent when the wheat diploidizing mechanism is active.


Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 978-983 ◽  
Author(s):  
A. Charpentier ◽  
M. Feldman ◽  
Y. Cauderon

Chromosome pairing at first meiotic metaphase was studied in hybrids between the common wheat cultivar Chinese Spring (CS) and an induced autotetraploid line derived from diploid Agropyron elongatum. The latter was found to carry genes for homoeologous pairing. To determine the chromosomal location of these and other genes that control pairing, disomic addition lines of A. elongatum in the cv. Chinese Spring were crossed with tetraploid cytotypes of A. elongatum, and pairing was then compared in the resulting hybrids and in hybrids between cv. Chinese Spring and tetraploid A. elongatum. The elongatum chromosomes were classified into those that suppress (6E), promote (5E, 3E, and possibly 1E), or have no effect on pairing (4E). The effect of chromosomes 2E and 7E was not studied. Chromosomes 5E and 3E differed in their effect on the degree and pattern of chromosome pairing. These findings are compared with the available data on the control of pairing in A. elongatum and in other Triticinae species.Key words: chromosome pairing, pairing promoter, Triticum, common wheat, Agropyron.


Author(s):  
A. G. Abramov ◽  
◽  
I.N. Abramova

The article presents the results of the influence of the magnitude of heterosis on the main elements of the formation of yield (grain size and productivity of the main spike) of spring wheat in the Irkutsk region. The following were used as maternal varieties: Irgina, Krasnoyarskaya 83, Tulun 15, Tselinnaya 60, Altayskaya 92, Niva 2 and a variety from Mongolia Orkhon 85, as testers - Skala, Angara 86, Tulunskaya 12 The best indicators of hypothetical heterosis were manifested by the number of grains in ear in combinations Krasnoyarskaya 83 × Angara 86, Krasnoyarskaya 83 × Skala, Altai 92 × Skala (81.6 ... 85.7%). In terms of grain weight from the main spike, the best results of hypothetical heterosis were noted in hybrid combinations Krasnoyarskaya 83 × Angara 86, Orkhon 85 × Angara 86, Ni-va × Angara 86, Altai 92 × Angara 86 (100.0 ... 130.7%) ... Krasnoyarskaya 83 × Angara 86, Altai 92 × Angara 86, Or-khon × Angara 86 are recognized as the best hybrid combinations that can give the greatest yield of transgressive forms of elite plants.


2013 ◽  
Vol 39 (8) ◽  
pp. 1386 ◽  
Author(s):  
Jian DONG ◽  
Hua YANG ◽  
Wan-Chun* ZHAO ◽  
Xiao-Yan LI ◽  
Qi-Jiao CHEN ◽  
...  

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