The effect of increased dosage of wheat chromosomes on chromosome pairing and an analysis of the chiasma frequencies of individual wheat bivalents

1985 ◽  
Vol 27 (4) ◽  
pp. 421-425 ◽  
Author(s):  
T. E. Miller ◽  
S. M. Reader

By crossing the 'Chinese Spring' wheat tetrasomic series with rye, 21 different hybrid genotypes were produced, each with a single different homologous pair of wheat chromosomes. These hybrids enable the effect on chromosome pairing to be assessed for an extra dose of each of the 21 chromosomes. Significant effects were observed with eight of the chromosomes. Chiasma frequencies for each of the 21 pairs of chromosomes were also studied and the differences between the chromosomes were reported. The correlation between chromosome pairing and chiasma formation and chiasma frequency differences between bivalents and genomes are discussed.Key words: wheat, chromosome pairing, chiasma frequencies.


Genome ◽  
1987 ◽  
Vol 29 (6) ◽  
pp. 888-891 ◽  
Author(s):  
P. K. Gupta ◽  
G. Fedak

An attempt was made to determine the inheritance of the rye genes which induce high chiasma frequency in hybrids with wheat and to study if the ability of rye to induce partial amphiploidy in hybrids with wheat was heritable. Five to eight F2 pollen plants were derived from seeds taken from each of three F1 plants that had given high chiasma frequency in hybrids with 'Chinese Spring' wheat in earlier studies. Similarly, six to seven F2 pollen plants were derived from each of three F1 plants that had given partial amphiploids in hybrids with 'Chinese Spring' wheat in earlier studies. Chiasma frequency was studied in 127 hybrids with 'Chinese Spring' wheat. In the present study, significant differences in chiasma frequency were observed (i) among the 38 families represented by 127 plants, and (ii) between two groups of three sets each, one known for inducing high pairing and the other known for inducing partial amphiploidy associated with low pairing in wheat × F1 rye plants. Significant variation was also observed between families within sets (each originated from one F1 rye plant) suggesting that F2 rye plants derived from the same F1 plants also differed genetically for inducing heterogenetic (homoeologous) pairing in wheat × rye hybrids. One of the six sets particularly showed significantly higher pairing with a mean of 2.13 per cell (individual hybrids gave a chiasma frequency as high as a mean of 6.07 per cell) as against a range of 0.96 to 1.18 in the remaining five sets, suggesting accumulation of genes in F2 rye plants for inducing pairing in wheat × rye hybrids. It is expected that by intermating the segregating rye plants, it should be possible to accumulate genes and eventually to isolate homozygous lines inducing high pairing in hybrids with wheat. Contrary to expectation, no partial amphiploids were obtained in a study of 127 wheat × F2 rye hybrids, although three of the six F1 rye plants had earlier given partial amphiploids in wheat × F1 rye hybrids. Key words: intergeneric hybrids, wheat, rye, genetic control, chromosome pairing.



1986 ◽  
Vol 28 (4) ◽  
pp. 624-627 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak

Two groups of three-way hybrids were produced by crossing F1 hybrids of 'Petkus' × 'Prolific' rye (2n = 14) and 'Prolific' × 'Puma' rye (2n = 14) onto 'Chinese Spring' wheat (2n = 42). Meiosis was studied in 89 plants from 29 families from the first combination and in 36 plants from 11 families in the second cross. In three families from the first combination ('Petkus' × 'Prolific') five partial amphiploids with chromosome numbers of 2n = 35, 36, 36, 38, and 41 were identified. The mean bivalent frequencies in five hybrids were 6.71, 7.73, 8.10, 9.94, and 13.00, suggesting that the number of bivalents was generally equal to the number of chromosomes in excess of the expected chromosome number of 2n = 28. These five plants were partial or incomplete amphiploids and their origin was attributed to duplication of a portion of the wheat complement after fertilization.Key words: partial amphiploids, hybrids (intergeneric), Triticum, Secale, chromosome pairing.



1983 ◽  
Vol 25 (4) ◽  
pp. 319-323 ◽  
Author(s):  
J. Hutchinson ◽  
T. E. Miller ◽  
S. M. Reader

The meiotic chromosome pairing of one 'Chinese Spring' wheat aneuhaploid (3AL) and two 'Chinese Spring' aneuploid × rye hybrids (N3A-T3B and N5B-T5D × rye) were studied. These genotypes all display higher than normal levels of pairing which were analysed with the aid of the technique of C-banding. The results show that the pattern of pairing is neither random nor of an unrestricted homoeologous nature. Pairing is more frequent between unhanded (A and D genome) chromosomes, than between either unhanded (A or D genome) and banded (B or R genome) chromosomes, or between banded (B and R genome) chromosomes.



1983 ◽  
Vol 25 (6) ◽  
pp. 634-641 ◽  
Author(s):  
T. E. Miller ◽  
S. M. Reader ◽  
M. D. Gale

Differences in the level of chromosome pairing in hybrids between 'Chinese Spring' wheat homoeologous group 3 aneuploids and rye and in homoeologous group 3 aneuhaploids were studied. Factors affecting chromosome pairing were detected or confirmed on both arms of the chromosomes of homoeologous group 3 in wheat. Effects were also identified on chromosome 3R of rye and a chromosome of Hordeum bulbosum. Factors affecting crossability between 'Chinese Spring' wheat and H. bulbosum were also found on chromosomes 3A, 3B, and 3D. A correlation was shown between increased pairing and reduced crossability.



Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 8-11
Author(s):  
H. S. Balyan ◽  
G. Fedak

Three hybrids of Triticum turgidum cv. Ma with Hordeum californicum × T. aestivum cv. Chinese Spring amphiploid were obtained at a frequency of 1.6% of the pollinated florets. Meiotic analysis of the hybrid plants revealed an average chiasma frequency per pollen mother cell ranging from 15.27 to 17.60. The lower than expected chromosome pairing in the hybrid plants was attributed to the suppression of pairing between homologous wheat chromosomes by pairing regulatory gene(s) in H. californicum.Key words: intergeneric hybrids, Hordeum californicum, Triticum turgidum, meiosis, chromosome pairing.





Planta ◽  
2001 ◽  
Vol 212 (5-6) ◽  
pp. 829-834 ◽  
Author(s):  
Lisa A. Papernik ◽  
Ananda S. Bethea ◽  
Theresa E. Singleton ◽  
Jurandir V. Magalhaes ◽  
David F. Garvin ◽  
...  




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