Rapeseed and Mustard

Downey, R. K.; Klassen, A. J.; Stringam, G. R.

doi:10.2135/1980.hybridizationofcrops.c35

Cited by 41 publications

(13 citation statements)

References 15 publications

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“…In all of the species in the current study, the single anthers did not rotate, but remained introrse. This has previously been reported in Leavenworthia [ 13 ] and cultivated Brassica species [ 26 , 27 ].…”

Section: Discussionsupporting

confidence: 79%

Is floral structure a reliable indicator of breeding system in the Brassicaceae?

et al. 2017

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This study investigated the usefulness of floral characters as a potential indicator of breeding system in the Brassicaceae. Initially, pod set, seed set and pollen tube growth experiments were carried out to confirm the breeding systems of 53 lines representing 25 different cultivated and weedy species from the Brassicaceae. The results of the pod set tests clearly differentiated between self-compatible and self-incompatible species. Floral characters were then evaluated on one or more lines of each of the 25 species. Fourteen floral characters were evaluated including, flower diameter, Cruden’s outcrossing index, timing and direction of dehiscence and pollen-ovule ratio. Significant differences between species were evident in all of the floral characteristics evaluated. Flower diameter was generally larger in self-incompatible species than self-compatible species and pollen/ovule ratio was generally higher in self-incompatible species than self-compatible species. However, none of the floral characteristics was able to clearly differentiate the self-compatible and self-incompatible species and allow prediction of the breeding system with absolute confidence. The floral characteristic which was most effective at differentiating the two groups was anther direction at dehiscence.

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Section: Discussionsupporting

confidence: 79%

Is floral structure a reliable indicator of breeding system in the Brassicaceae?

et al. 2017

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“…[ 52 ]; this might have caused more rapid LD decay and subsequently shorter-range haplotype blocks in A-subgenome chromosomes in the present materials after hybridisations with B. rapa . Although breeders have used interspecific crosses to improve agronomic traits and increase C-subgenome genetic diversity in B. napus , it is extremely difficult to obtain viable hybrid seeds from B. napus × B. oleracea crosses [ 53 , 54 ], causing a constraint in the ability to diversify the C-subgenome genetic component. It is thought that B. napus arose only in post-neolithic times and from only a small number of independent hybridisation events [ 27 ], and that the Chinese rapeseed genepool may predominantly represent only one or a few of these events.…”

Section: Discussionmentioning

confidence: 99%

Sub-genomic selection patterns as a signature of breeding in the allopolyploid Brassica napus genome

2014

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BackgroundHigh-density single-nucleotide polymorphism (SNP) genotyping arrays are a powerful tool for genome-wide association studies and can give valuable insight into patterns of population structure and linkage disequilibrium (LD). In this study we used the Brassica 60kSNP Illumina consortium genotyping array to assess the influence of selection and breeding for important agronomic traits on LD and haplotype structure in a diverse panel of 203 Chinese semi-winter rapeseed (Brassica napus) breeding lines.ResultsPopulation structure and principal coordinate analysis, using a subset of the SNPs, revealed diversification into three subpopulations and one mixed population, reflecting targeted introgressions from external gene pools during breeding. Pairwise LD analysis within the A- and C-subgenomes of allopolyploid B. napus revealed that mean LD, at a threshold of r2 = 0.1, decayed on average around ten times more rapidly in the A-subgenome (0.25-0.30 Mb) than in the C-subgenome (2.00-2.50 Mb). A total of 3,097 conserved haplotype blocks were detected over a total length of 182.49 Mb (15.17% of the genome). The mean size of haplotype blocks was considerably longer in the C-subgenome (102.85 Kb) than in the A-subgenome (33.51 Kb), and extremely large conserved haplotype blocks were found on a number of C-genome chromosomes. Comparative sequence analysis revealed conserved blocks containing homoloeogous quantitative trait loci (QTL) for seed erucic acid and glucosinolate content, two key seed quality traits under strong agronomic selection. Interestingly, C-subgenome QTL were associated with considerably greater conservation of LD than their corresponding A-subgenome homoeologues.ConclusionsThe data we present in this paper provide evidence for strong selection of large chromosome regions associated with important rapeseed seed quality traits conferred by C-subgenome QTL. This implies that an increase in genetic diversity and recombination within the C-genome is particularly important for breeding. The resolution of genome-wide association studies is also expected to vary greatly across different genome regions.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-1170) contains supplementary material, which is available to authorized users.

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“…Whether the reshaping of homologous recombination observed in AAC allotriploids similarly occurs in CCA allotriploids, resulting from the cross between B. napus and its other diploid progenitor B. oleracea, remains to be deciphered (currently in progress). Even if these later CCA hybrids are more difficult to generate [76], improved recombination between homologous C chromosomes would also strongly benefit B. napus breeding programs. In fact, different studies revealed that it could be useful to introduce into B. napus new diversity from B. oleracea [77], such as clubroot resistance traits [78], and conversely from B. napus to B. oleracea [79].…”

Section: Development Of the Strategy On Other Modelsmentioning

confidence: 99%

A Modified Meiotic Recombination in Brassica napus Largely Improves Its Breeding Efficiency

Boideau

Pelé

Tanguy

et al. 2021

Biology

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Meiotic recombination is the main tool used by breeders to generate biodiversity, allowing genetic reshuffling at each generation. It enables the accumulation of favorable alleles while purging deleterious mutations. However, this mechanism is highly regulated with the formation of one to rarely more than three crossovers, which are not randomly distributed. In this study, we showed that it is possible to modify these controls in oilseed rape (Brassica napus, AACC, 2n = 4x = 38) and that it is linked to AAC allotriploidy and not to polyploidy per se. To that purpose, we compared the frequency and the distribution of crossovers along A chromosomes from hybrids carrying exactly the same A nucleotide sequence, but presenting three different ploidy levels: AA, AAC and AACC. Genetic maps established with 202 SNPs anchored on reference genomes revealed that the crossover rate is 3.6-fold higher in the AAC allotriploid hybrids compared to AA and AACC hybrids. Using a higher SNP density, we demonstrated that smaller and numerous introgressions of B. rapa were present in AAC hybrids compared to AACC allotetraploid hybrids, with 7.6 Mb vs. 16.9 Mb on average and 21 B. rapa regions per plant vs. nine regions, respectively. Therefore, this boost of recombination is highly efficient to reduce the size of QTL carried in cold regions of the oilseed rape genome, as exemplified here for a QTL conferring blackleg resistance.

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Rapeseed and Mustard

Cited by 41 publications

References 15 publications

Is floral structure a reliable indicator of breeding system in the Brassicaceae?

Is floral structure a reliable indicator of breeding system in the Brassicaceae?

Sub-genomic selection patterns as a signature of breeding in the allopolyploid Brassica napus genome

A Modified Meiotic Recombination in Brassica napus Largely Improves Its Breeding Efficiency

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