Frequent nonreciprocal translocations in the amphidiploid genome of oilseed rape (Brassica napus)

Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1112-1121 ◽  
Author(s):  
A. G. Sharpe ◽  
I. A. P. Parkin ◽  
D. J. Keith ◽  
D. J. Lydiate
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Doubled Haploid ◽  
Microspore Culture ◽  
Homoeologous Recombination ◽  
Linkage Groups ◽  
Rflp Map ◽  
A Genome ◽  
C Genome ◽  
Marker Loci

A RFLP map of Brassica napus, consisting of 277 loci arranged in 19 linkage groups, was produced from genetic segregation in a combined population of 174 doubled-haploid microspore-derived lines. The integration of this map with a B. napus map derived from a resynthesized B. napus × oilseed rape cross allowed the 10 linkage groups of the B. napus A genome and the 9 linkage groups of the C genome to be identified. Collinear patterns of marker loci on different linkage groups suggested potential partial homoeologues. RFLP patterns consistent with aberrant chromosomes were observed in 9 of the 174 doubled-haploid lines. At least 4 of these lines carried nonreciprocal, homoeologous translocations. These translocations were probably the result of homoeologous recombination in the amphidiploid genome of oilseed rape, suggesting that domesticated B. napus is unable to control chromosome pairing completely. Evidence for genome homogenization in oilseed rape is presented and its implications on genetic mapping in amphidiploid species is discussed. The level of polymorphism in the A genome was higher than that in the C genome and this might be a general property of oilseed rape crosses.Key words: restriction fragment length polymorphism, genetic linkage map, homoeologous recombination, microspore culture, doubled haploid.

Patterns of genome duplication within the Brassica napus genome

Genome ◽  
2003 ◽  
Vol 46 (2) ◽  
pp. 291-303 ◽  
Author(s):  
I A.P Parkin ◽  
A G Sharpe ◽  
D J Lydiate
Keyword(s):  
Brassica Napus ◽  
Genome Duplication ◽  
Chromosomal Rearrangements ◽  
Centric Fusion ◽  
Linkage Groups ◽  
Gross Chromosomal Rearrangements ◽  
A Genome ◽  
C Genome ◽  
Homologous Locus ◽  
Duplicate Loci

The progenitor diploid genomes (A and C) of the amphidiploid Brassica napus are extensively duplicated with 73% of genomic clones detecting two or more duplicate sequences within each of the diploid genomes. This comprehensive duplication of loci is to be expected in a species that has evolved through a polyploid ancestor. The majority of the duplicate loci within each of the diploid genomes were found in distinct linkage groups as collinear blocks of linked loci, some of which had undergone a variety of rearrangements subsequent to duplication, including inversions and translocations. A number of identical rearrangements were observed in the two diploid genomes, suggesting they had occurred before the divergence of the two species. A number of linkage groups displayed an organization consistent with centric fusion and (or) fission, suggesting this mechanism may have played a role in the evolution of Brassica genomes. For almost every genetically mapped locus detected in the A genome a homologous locus was found in the C genome; the collinear arrangement of these homologous markers allowed the primary regions of homoeology between the two genomes to be identified. At least 16 gross chromosomal rearrangements differentiated the two diploid genomes during their divergence from a common ancestor.Key words: genome evolution, Brassicaeae, polyploidy, homoeologous linkage groups.

scholarly journals Utilisation of doubled haploids in winter oilseed rape (Brassica napus L.) breeding

2012 ◽  
Vol 38 (No. 1) ◽  
pp. 50-54 ◽  
Author(s):  
V. Kučera ◽  
M. Vyvadilová ◽  
M. Klíma
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Doubled Haploid ◽  
Microspore Culture ◽  
Doubled Haploids ◽  
Winter Oilseed Rape ◽  
Brassica Napus L ◽  
The Czech Republic ◽  
Yield Parameters ◽  
The World

A survey of development and prospects of the utilisation of doubled haploid techniques in rapeseed breeding in the world and in the Czech Republic is presented. The first utilisation of spontaneously occurred haploids from Brassica napus inbreeding programmes is described. The development of techniques of anther and later microspore culture is outlined. Special emphasis is given to the practical use of doubled haploids for the improvement of the effectiveness of breeding new productive cultivars. Some partial results of evaluation of yield parameters and resistance to important diseases in the obtained doubled haploid lines of winter oilseed rape are shown. The literary review and present results indicate, that the doubled haploid technique can be effectively used for the development of homozygous oilseed rape lines as an alternative to conventional methods.

Latent S alleles are widespread in cultivated self-compatible Brassica napus

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 257-265 ◽  
Author(s):  
U U Ekuere ◽  
I A.P Parkin ◽  
C Bowman ◽  
D Marshall ◽  
D J Lydiate
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Self Incompatibility ◽  
S Locus ◽  
Winter Oilseed Rape ◽  
A Genome ◽  
C Genome ◽  
S Alleles ◽  
Crop Types ◽  
S Allele

The genetic control of self-incompatibility in Brassica napus was investigated using crosses between resynthesized lines of B. napus and cultivars of oilseed rape. These crosses introduced eight C-genome S alleles from Brassica oleracea (S16, S22, S23, S25, S29, S35, S60, and S63) and one A-genome S allele from Brassica rapa (SRM29) into winter oilseed rape. The inheritance of S alleles was monitored using genetic markers and S phenotypes were determined in the F1, F2, first backcross (B1), and testcross (T1) generations. Two different F1 hybrids were used to develop populations of doubled haploid lines that were subjected to genetic mapping and scored for S phenotype. These investigations identified a latent S allele in at least two oilseed rape cultivars and indicated that the S phenotype of these latent alleles was masked by a suppressor system common to oilseed rape. These latent S alleles may be widespread in oilseed rape varieties and are possibly associated with the highly conserved C-genome S locus of these crop types. Segregation for S phenotype in subpopulations uniform for S genotype suggests the existence of suppressor loci that influenced the expression of the S phenotype. These suppressor loci were not linked to the S loci and possessed suppressing alleles in oilseed rape and non-suppressing alleles in the diploid parents of resynthesized B. napus lines.Key words: self-incompatibility, B. oleracea, B. rapa, S locus, suppression.

Identification of the A and C genomes of amphidiploid Brassica napus (oilseed rape)

Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1122-1131 ◽  
Author(s):  
I. A. P. Parkin ◽  
A. G. Sharpe ◽  
D. J. Keith ◽  
D. J. Lydiate
Keyword(s):  
Brassica Napus ◽  
Linkage Map ◽  
Oilseed Rape ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Resynthesized Brassica Napus ◽  
Disomic Inheritance ◽  
A Genome ◽  
C Genome ◽  
Homoeologous Chromosomes

A genetic linkage map consisting of 399 RFLP-defined loci was generated from a cross between resynthesized Brassica napus (an interspecific B. rapa × B. oleracea hybrid) and "natural" oilseed rape. The majority of loci exhibited disomic inheritance of parental alleles demonstrating that B. rapa chromosomes were each pairing exclusively with recognisable A-genome homologues in B. napus and that B. oleracea chromosomes were pairing similarly with C-genome homologues. This behaviour identified the 10 A genome and 9 C genome linkage groups of B. napus and demonstrated that the nuclear genomes of B. napus, B. rapa, and B. oleracea have remained essentially unaltered since the formation of the amphidiploid species, B. napus. A range of unusual marker patterns, which could be explained by aneuploidy and nonreciprocal translocations, were observed in the mapping population. These chromosome abnormalities were probably caused by associations between homoeologous chromosomes at meiosis in the resynthesized parent and the F1 plant leading to nondisjunction and homoeologous recombination.Key words: genetic linkage map, homoeologous recombination, Brassica rapa, Brassica oleracea, genome organization.

scholarly journals Detection and Effects of a Homeologous Reciprocal Transposition in Brassica napus

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1569-1577
Author(s):  
Thomas C Osborn ◽  
David V Butrulle ◽  
Andrew G Sharpe ◽  
Kathryn J Pickering ◽  
Isobel A P Parkin ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Genetic Mapping ◽  
Doubled Haploid ◽  
Selective Advantage ◽  
F1 Hybrids ◽  
Rflp Markers ◽  
Cytological Analysis ◽  
Linkage Groups ◽  
Homeologous Chromosomes ◽  
Seed Yields

Abstract A reciprocal chromosomal transposition was identified in several annual oilseed Brassica napus genotypes used as parents in crosses to biennial genotypes for genetic mapping studies. The transposition involved an exchange of interstitial homeologous regions on linkage groups N7 and N16, and its detection was made possible by the use of segregating populations of doubled haploid lines and codominant RFLP markers. RFLP probes detected pairs of homeologous loci on N7 and N16 for which the annual and biennial parents had identical alleles in regions expected to be homeologous. The existence of an interstitial reciprocal transposition was confirmed by cytological analysis of synaptonemal complexes of annual × biennial F1 hybrids. Although it included approximately one-third of the physical length of the N7 and N16 chromosomes, few recombination events within the region were recovered in the progenies of the hybrids. Significantly higher seed yields were associated with the parental configurations of the rearrangement in segregating progenies. These progenies contained complete complements of homeologous chromosomes from the diploid progenitors of B. napus, and thus their higher seed yields provide evidence for the selective advantage of allopolyploidy through the fixation of intergenomic heterozygosity.

Mapping QTL controlling agronomic traits in a doubled haploid population of winter oilseed rape (Brassica napus L.)

2018 ◽  
Vol 97 (5) ◽  
pp. 1389-1406 ◽  
Author(s):  
Farshad Fattahi ◽  
Barat Ali Fakheri ◽  
Mahmood Solouki ◽  
Christian Möllers ◽  
Abbas Rezaizad
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Doubled Haploid ◽  
Agronomic Traits ◽  
Doubled Haploid Population ◽  
Winter Oilseed Rape ◽  
Brassica Napus L ◽  
Mapping Qtl ◽  
Haploid Population

Indistinguishable patterns of recombination resulting from male and female meioses in Brassica napus (oilseed rape)

Genome ◽  
1997 ◽  
Vol 40 (1) ◽  
pp. 49-56 ◽  
Author(s):  
A. L. Kelly ◽  
A. G. Sharpe ◽  
J. H. Nixon ◽  
D. J. Lydiate ◽  
E. J. Evans
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Genetic Maps ◽  
Linkage Groups ◽  
Male Population ◽  
Female Population ◽  
Male And Female ◽  
Male Gametes ◽  
Genome Map ◽  
Backcross Populations

An F1 individual derived from a cross between two distinct lines of spring oilseed rape (Brassica napus) was used to produce a pair of complementary backcross populations, each consisting of 90 individuals. The F1 donated male gametes to the Male population and female gametes to the Female population. Genetic maps were generated from both populations and aligned using 117 common loci to form an integrated genome map of B. napus with 243 RFLP-defined loci. A comparison of the frequency and distribution of crossovers in the two populations of F1 gametes (assayed in the Male and Female populations) detected no differences. The genetic maps derived from the Male and Female populations each consisted of 19 linkage groups spanning 1544 and 1577 cM, respectively. The maps were aligned with other B. napus maps, and all 19 equivalent linkage groups were unambiguously assigned. The genetic size and general organisation of the new maps were comparable with those of pre-existing B. napus maps in most respects, except that the levels of polymorphism in the constituent A and C genomes were unusually similar in the new cross.Key words: genetic linkage map, sex differences, recombination frequency, segregation distortion.

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