Befruchtungsbiologie und Allopolyploidie bei der Artkreuzung Sommerraps x Chinakohl

Jahr, W.

doi:10.1007/bf00710467

Cited by 9 publications

(2 citation statements)

References 29 publications

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“…In general, the fertility of F 1 hybrids was low, and male sterility was common. The fertility of hybrid plants was increased in some cases when the chromosome number was doubled (Morinaga and Fukushima, 1933;U, 1935;Ttiresson and Nordenski6d, 1943;Mizushima, 1950b;Jahr, 1962;Nwankiti, 1971;Chiang et al, 1977;Heyn, 1977;Chevre et al, 1991). Increase in the chromosome number can occur spontaneously, either in the Fa hybrid or in later generations, but can lead to decreased as well as increased fertility.…”

Section: Resultsmentioning

confidence: 93%

Opportunities for gene transfer from transgenic oilseed rape (Brassica napus) to related species

Scheffler

Dale

1994

Transgenic Research

168

114

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Before novel transgenic plant genotypes are grown outside containment facilities and evaluated under field conditions, it is necessary to complete a risk assessment to consider the possible consequences of that release. An important aspect of risk assessment is to consider the likelihood and consequences of the transgene being transferred by cross-pollination to related species, including other crops, weeds and ruderal populations. The purpose of this report is to review the literature to assess the ease with which Brassica napus can hybridize with related species. The evidence for hybridization is considered at three levels: a) by open pollination, b) by hand pollination and c) by the use of in vitro ovule and embryo rescue techniques; and also examines the fertility and vigour of the F 1, F 2 and backcross generations. Four species are reported to hybridize with B. napus by open pollination: B. rapa and B. juncea using fully fertile parents; and B. adpressa and R. raphanistrurn using a male-sterile B. napus parent. Seventeen species are reported to form hybrids (including the four species above) with B. napus when pollination is carried out manually. At least 12 of these species were unable to form F 2 progeny, and eight were unable to produce progeny when the Fa was backcrossed to one of the parental species. Many factors will influence the success of hybridization under field conditions, including: distance between the parents, synchrony of flowering, method of pollen spread, specific parental genotypes used, direction of the cross and the environmental conditions. Even where there is a possibility of hybridization between B. napus and a related species growing in the vicinity of a release, poor vigour and high sterility in the hybrids will generally mean that hybrids and their progeny will not survive in either an agricultural or natural habitat.

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Section: Resultsmentioning

confidence: 93%

Opportunities for gene transfer from transgenic oilseed rape (Brassica napus) to related species

Scheffler

Dale

1994

Transgenic Research

168

114

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“…B. nc. has been obtained either from "meiotic" polyploidization (FRAND-SEN et al 1932;JAHR 1962) or as in this work from "mitotic" polyploidization by colchicine treat men t.…”

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confidence: 92%

Cytogenetic and breeding studies with Brassica

Nwankiti

2009

Hereditas

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A summary of studies made with Brassica napocampestris (B. nc.), 2n=58, obtained by colchicine treatment of the F1 hybrid between B. napus and B. campestris is given. Cytological studies of the primary hybrids reveal that the single genome of B. oleracea in B. napus—“c1”– may be utilized for elucidating the basic genomic number of the genus Brassica. Based on the mode of chromosome pairing at MI in the primary hybrids, the conclusion was drawn of a basic genomic number of 6. From the backcrosses of these F1 hybrids to B. campestris types, the same conclusion was indirectly arrived at. The backcross experiments with the F1 hybrids indicated the possibility of extracting not only a whole genome “a1” from B. napus but also, the supposed basic genome. For the hexaploid plants (2n=58), meiotic studies revealed that besides many bivalents there were some multivalents. Anaphase movements were slightly disturbed by bridges, presumed to result from inversions. On the whole, secondary balance accompanied by chromosomal alterations, may be responsible for the present serial polyploidy in the tribe Brassiceae. Aneuploid plants were not encountered in the hexaploid populations used. However, by continuous backcrosses of F1 hybrids (2n=29) to the hexaploids, plants with chromosome numbers close to 58 were obtained which showed fairly good seed fertility. It is suggested that selection against aneuploidy occurs at the gametic stage and this would account for the relatively low pollen fertilities found in the hexaploid B. nc. types.

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Genome Manipulations

Prakash¹,

Chopra²

1993

Monographs on Theoretical and Applied Genetics

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Befruchtungsbiologie und Allopolyploidie bei der Artkreuzung Sommerraps x Chinakohl

Cited by 9 publications

References 29 publications

Opportunities for gene transfer from transgenic oilseed rape (Brassica napus) to related species

Opportunities for gene transfer from transgenic oilseed rape (Brassica napus) to related species

Cytogenetic and breeding studies with Brassica

Genome Manipulations

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