Successful induction of trigenomic hexaploid Brassica from a triploid hybrid of B. napus L. and B. nigra (L.) Koch

Pradhan, Aneeta; Nelson, Matthew N.; Cowling, Wallace; Yan, Guijun

doi:10.1007/s10681-010-0218-8

Cited by 35 publications

(30 citation statements)

References 42 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For MM.AABB and BBCC.MM with higher fertility, advancing generations are needed to establish diploid-like meiotic behavior and improve fertility. Other Brassica allohexaploids involving A, B, and C genomes also suffered from some extents of cytological instability and low fertility (Ge et al 2009;Pradhan et al 2010;Tian et al 2010;Chen et al 2011). Therefore, long time and selection are needed to stabilize these allohexaploids.…”

Section: Discussionmentioning

confidence: 99%

“…Although there are some highly successful hexaploid crops in nature, such as oat, triticale, and bread wheat, no natural allohexaploid species in Brassica are found. However, some efforts were recently made to produce Brassica allohexaploids (AABBCC, 2n = 54) (Ge et al 2009;Pradhan et al 2010;Tian et al 2010;Chen et al 2011). These artificially synthesized allohexaploids can be used as a trigenomic bridge to increase genetic diversity in allopolyploid Brassica crops, or to develop new Brassica species for the future.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Different fertility and meiotic regularity in allohexaploids derived from trigenomic hybrids between three cultivated Brassica allotetraploids and B. maurorum

Yao

2011

Plant Cell Rep

View full text Add to dashboard Cite

The wild species Brassica maurorum Durieu (MM, 2n = 16) is useful for the improvement of Brassica crops. Herein, interspecific reciprocal crosses between B. maurorum and three cultivated Brassica allotetraploids were carried out with the aid of embryo rescue. Trigenomic hybrids with Brassica napus (AACC, 2n = 38) and Brassica carinata (BBCC, 2n = 34) were produced from reciprocal crosses, but the hybrids with Brassica juncea (AABB, 2n = 36) were obtained only when B. maurorum was used as female. All the hybrids were morphologically intermediate between their parents, and were male and female sterile. By in vitro chromosome doubling of the trigenomic hybrids, the allohexaploids (AACC.MM/MM.AACC, 2n = 54; BBCC.MM, 2n = 50; MM.AABB, 2n = 52) were established and characterized for their phenotype and cytology. The fertilities of three allohexaploids were different, for AACC.MM and MM.AACC failed to produce seeds by selfing, but BBCC.MM showed low seed-set and MM.AABB had good seed-set. They also expressed variable extents of male meiotic regularity as to chromosome pairing and segregation, with MM.AABB > BBCC.MM > AACC.MM/MM.AACC, the same order as their fertility. So their meiotic behavior contributed to the fertility. Finally, the potential of these allohexaploids as a bridge for genetic improvement of Brassica crops was discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Different fertility and meiotic regularity in allohexaploids derived from trigenomic hybrids between three cultivated Brassica allotetraploids and B. maurorum

Yao

2011

Plant Cell Rep

View full text Add to dashboard Cite

show abstract

“…However, Iwasa (1964) found poor meiotic stability in the same species cross that failed to improve even up to the F 5 selfing generation, resulting in loss of fertility and hence usefulness of this crop. Allohexaploid Brassica has also been created as a bridge to transfer disease resistance between B. nigra and B. napus (Sjödin and Glimelius 1989;Pradhan et al 2010) to produce yellow-seeded B. napus by crosses between B. rapa and B. carinata (Meng et al 1998;Rahman 2001) to transfer cytoplasmic male sterility from B. oleracea to B. juncea (Arumugam et al 1996) and to resynthesize B. napus from B. rapa and B. carinata (Li et al 2004). However, although these studies demonstrate the ease of production of allohexaploid Brassica from crosses between the diploid and allotetraploid species, meiotic stability and fertility was not assessed in these allohexaploid types.…”

mentioning

confidence: 99%

The Fate of Chromosomes and Alleles in an AllohexaploidBrassicaPopulation

et al. 2014

View full text Add to dashboard Cite

Production of allohexaploid Brassica (2n = AABBCC) is a promising goal for plant breeders due to the potential for hybrid heterosis and useful allelic contributions from all three of the Brassica genomes present in the cultivated diploid (2n = AA, 2n = BB, 2n = CC) and allotetraploid (2n = AABB, 2n = AACC, and 2n = BBCC) crop species (canola, cabbages, mustards). We used highthroughput SNP molecular marker assays, flow cytometry, and fluorescent in situ hybridization (FISH) to characterize a population of putative allohexaploids derived from self-pollination of a hybrid from the novel cross (B. napus 3 B. carinata) 3 B. juncea to investigate whether fertile, stable allohexaploid Brassica can be produced. Allelic segregation in the A and C genomes generally followed Mendelian expectations for an F 2 population, with minimal nonhomologous chromosome pairing. However, we detected no strong selection for complete 2n = AABBCC chromosome complements, with weak correlations between DNA content and fertility (r 2 = 0.11) and no correlation between missing chromosomes or chromosome segments and fertility. Investigation of next-generation progeny resulting from one highly fertile F 2 plant using FISH revealed general maintenance of high chromosome numbers but severe distortions in karyotype, as evidenced by recombinant chromosomes and putative loss/duplication of A-and C-genome chromosome pairs. Our results show promise for the development of meiotically stable allohexaploid lines, but highlight the necessity of selection for 2n = AABBCC karyotypes.T HE Brassica genus contains the largest number of cultivated crop species of any plant genus (Dixon 2007). Six major crop species are B. rapa (Chinese cabbage, turnip), B. oleracea (cabbage, cauliflower, broccoli), B. nigra (black mustard), B. napus (canola, rapeseed), B. juncea (Indian mustard, leaf mustard), and B. carinata (Ethiopian mustard). These six species share a unique genomic relationship: progenitor diploid species B. rapa (2n = AA), B. oleracea (2n = CC), and B. nigra (2n = BB) gave rise to the allotetraploid species B. juncea (2n = AABB), B. napus (2n = AACC), and B. carinata (2n = BBCC) through pairwise crosses (Morinaga 1934;U 1935). However, despite the fact that each pair of genomes coexists in an allotetraploid species, no naturally occurring allohexaploid species (2n = AABBCC) exists. In general, interspecific hybridization and polyploidy in plants are potent evolutionary mechanisms, allowing formation of new species with adaptation to a wider range of climatic conditions and greater "hybrid vigor" than their progenitor species (Otto and Whitton 2000;Leitch and Leitch 2008). Hence, production of an artificial allohexaploid in the agriculturally important Brassica genus could potentially give rise to new crop types with greater intersubgenomic heterosis ) and tolerance of a wider range of environmental conditions than preexisting Brassica crops (Chen et al. 2011).

show abstract

“…No allohexaploid (AABBCC) Brassica species is known, although trigenomic hybrids have been formed artificially on several occasions (Takeda and Takahata, 1996;Prakash et al, 2009;Yan et al, 2009;Pradhan et al 2010a). Allohexaploid crops, selected by ancient or modern farmers, are extremely important in agriculture-including two of the world's most widely adapted and important food crops bread wheat (Triticum aestivum) and oats (Avena sativa) (Murphy, 2007;Leitch and Leitch, 2008).…”

Section: Introductionmentioning

confidence: 99%