Publication Date
1989
Description
The Dactylis glomerata L. autopolyploid complex is very diverse and includes at least 15 diploid (2n = 2X = 14), 3 main natural tetraploid (2n = 4X = 28) and one hexaploid subspecies (2n = 6x = 42), each having a distinct phenotype and geographical distribution. The diploids are generally each confined to a single habitat (Borrill, 1978 ; Lumaret, 1988). In contrast, the three major 4X subspecies are generally distributed over a wide range of habitats and are favoured by man's activity (cultivation). Where there is considerable interpenetration of several types of climate, these 4X types may be connected by a whole range of intermediates originating from natural hybridization (Borrill, 1978, Lumaret, 1988). There are also several minor 4X types with more restricted distribution. Among these, several are morphologically indistinguishable from a particular 2X form. Theses 4X types are considered to have arisen from their counterpart 2X forms by autopolyploidization. Gametic non-reduction is thought to be responsible for the tetraploidization of Dactylis in nature (Zohary and Nur, 1959; Borrill, 1978). This meiotic abnormality has been also observed experimentally for either eggs or pollen (or both) from crosses between 2X and 4X Dactylis individuals (Carroll and Borrill, 1965; Van Santen et al., 1986; Lumaret, 1988). Genetic diversity of Dactylis has been studied at both ploidy levels using enzyme markers (Lumaret, 1988 and unpublished). The 2X can be regarded genetically as pure types which may have distinctive interesting agricultural characteristics. Up to now, only a small fraction of Dactylis genetic resources has been utilized for breeding. This concerns essentially a part of tetraploid subsp. glomerata. Gametic non-reduction has been used successfully in potato and red clover to transfer gene linkats and heterozygotic combinations from the 2X to the 4X level (Mendiburu and Peloquin, 1977; Parrott et al., 1985). Moreover, this method prevents the production of chimeras. The current objective of this work is to identify Dactylis plants from the several 2X subspecies that produce either 2n eggs or 2n pollen (or both) on a regular basis and that could be used for either bilateral or unilateral sexual tetraploidization.
Citation
Lumaret, Roselyne; Maceira, N; Haan, Anita De; and Delay, J, "Screening of 2N Gametes to Produce New Tetraploid Material from Diploids in Dactylis glomerata L." (2025). IGC Proceedings (1989-2023). 47.
https://uknowledge.uky.edu/igc/1989/session3/47
Included in
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Screening of 2N Gametes to Produce New Tetraploid Material from Diploids in Dactylis glomerata L.
The Dactylis glomerata L. autopolyploid complex is very diverse and includes at least 15 diploid (2n = 2X = 14), 3 main natural tetraploid (2n = 4X = 28) and one hexaploid subspecies (2n = 6x = 42), each having a distinct phenotype and geographical distribution. The diploids are generally each confined to a single habitat (Borrill, 1978 ; Lumaret, 1988). In contrast, the three major 4X subspecies are generally distributed over a wide range of habitats and are favoured by man's activity (cultivation). Where there is considerable interpenetration of several types of climate, these 4X types may be connected by a whole range of intermediates originating from natural hybridization (Borrill, 1978, Lumaret, 1988). There are also several minor 4X types with more restricted distribution. Among these, several are morphologically indistinguishable from a particular 2X form. Theses 4X types are considered to have arisen from their counterpart 2X forms by autopolyploidization. Gametic non-reduction is thought to be responsible for the tetraploidization of Dactylis in nature (Zohary and Nur, 1959; Borrill, 1978). This meiotic abnormality has been also observed experimentally for either eggs or pollen (or both) from crosses between 2X and 4X Dactylis individuals (Carroll and Borrill, 1965; Van Santen et al., 1986; Lumaret, 1988). Genetic diversity of Dactylis has been studied at both ploidy levels using enzyme markers (Lumaret, 1988 and unpublished). The 2X can be regarded genetically as pure types which may have distinctive interesting agricultural characteristics. Up to now, only a small fraction of Dactylis genetic resources has been utilized for breeding. This concerns essentially a part of tetraploid subsp. glomerata. Gametic non-reduction has been used successfully in potato and red clover to transfer gene linkats and heterozygotic combinations from the 2X to the 4X level (Mendiburu and Peloquin, 1977; Parrott et al., 1985). Moreover, this method prevents the production of chimeras. The current objective of this work is to identify Dactylis plants from the several 2X subspecies that produce either 2n eggs or 2n pollen (or both) on a regular basis and that could be used for either bilateral or unilateral sexual tetraploidization.
