Induced Mutation Affecting the Control of Meiotic Chromosome Pairing in Triticum aestivum

Nature ◽  
1966 ◽  
Vol 211 (5047) ◽  
pp. 368-369 ◽  
Author(s):  
RALPH RILEY ◽  
VICTOR CHAPMAN ◽  
ANGELA M. BELFIELD
1971 ◽  
Vol 18 (3) ◽  
pp. 311-328 ◽  
Author(s):  
A. M. Wall ◽  
Ralph Riley ◽  
Victor Chapman

SUMMARYPlants of Triticum aestivum (2n = 6x = 42) ditelocentric 5BL were treated with EMS in order to produce mutations in the 5B system by which meiotic pairing between homoeologous chromosomes is normally prevented. To check for the occurrence of mutation T. aestivum ditelo-5BL plants were pollinated with rye (Secale cereale 2n = 14) and meiosis was examined in the resulting hybrids.Wheat-rye hybrids were scored for the presence of mutants when the wheat parents were either the EMS-treated wheat plants, or their selfed derivatives, or their progenies obtained after pollination with untreated euploid individuals.Mutants were detected by each of these procedures and mutant gametes were produced by the treated ditelocentric plants with frequencies between 1·5 and 2·5%, but there were differences between the mutants in the extent to which homoeologous pairing occurred in the derived wheat-rye hybrids. The differences may have resulted from the occurrence of mutation at different loci or to different extents at the same locus.Two mutants, Mutant 10/13 and Mutant 61, were fixed in the homozygous condition. Mutant 10/13 was made homozygous both in the 5BL ditelocentric and in the euploid conditions but these genotypes regularly formed 21 bivalents at meiosis, and there was no indication of homoeologous pairing although the mutant 10/13 gave rise to homoeologous pairing in wheat-rye hybrids.


Nature ◽  
1966 ◽  
Vol 212 (5069) ◽  
pp. 1475-1477 ◽  
Author(s):  
RALPH RILEY ◽  
VICTOR CHAPMAN ◽  
R. M. YOUNG ◽  
ANGELA M. BELFIELD

1976 ◽  
Vol 28 (1) ◽  
pp. 37-45 ◽  
Author(s):  
T. E. Miller ◽  
Victor Chapman

SUMMARYEuploid and aneuploid plants of Triticum aestivum, variety Chinese Spring were pollinated with, pollen of Hordeum bulbosum. Euhaploids and aneuhaploids of Chinese Spring were obtained from the crosses. Meiotic chromosome pairing was analysed in 25 different aneuhaploids and the results were compared with those obtained from euhaploids. The evidence provided by the meiotic studies was used to identify chromosomes whose activities affected the genetic control of chromosome pairing.Meiosis was abnormal in a 23-chromosome aneuhaploid and in the 22-chromosome sectors of a chimaeral plant. Both plants were thought to have resulted from the incomplete elimination of the genome of H. bulbosum from hybrid embryos. It is suggested that the meiotic abnormalities in the two aneuhaploids were caused by the residual barley chromosomes.


Meiotic chromosome pairing is a process that is amenable to genetic and experimental analysis. The combined use of these two approaches allows for the process to be dissected into several finite periods of time in which the developmental stages of pairing can be precisely located. Evidence is now available, in particular in plants, that shows that the pairing of homologous chromosomes, as observed at metaphase I, is affected by events occurring as early as the last premeiotic mitosis; and that the maintenance of this early determined state is subsequently maintained by constituents (presumably proteins) that are sensitive to either colchicine, temperature or gene control. A critical assessment of this evidence in wheat and a comparison of the process of pairing in wheat with the course of meiotic pairing in other plants and animals is presented.


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