Non-reductional meiosis in aTriticum turgidum �Aegilops longissima hybrid and in backcrosses of its amphidiploid withT. turgidum (Poaceae)

Pignone, Domenico

doi:10.1007/bf00994095

Cited by 10 publications

(9 citation statements)

References 13 publications

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“…X gennarii supports the hypothesis of meiotic non-reduction which is reported to be more frequent in plants showing high rates of univalents at meiosis (HARLAN and DE WET 1975;GIRALDEZ and LACADENA 1976;BENAVENTE and ORELLANA 1986;PIGNONE 1993). In this case one has to hypothesize that 0.…”

Section: Discussionsupporting

confidence: 74%

Cytomorphological characterization of diploid and triploid individuals ofOrchis × gennariiReichenb. fil. (Orchidaceae)

D’Emerico¹,

Bianco²,

Pignone³

1996

Caryologia

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SUMMARY -Individuals of Orchis X gennarii, collected at different sites in Apulia (southern Italy), showed 34 or 52 chromosomes karyotypes. Chromosomal morphology and meiotic pairing were studied in both cytotypes and compared with the putative parental species: 0. mario and 0. papi/ionacea. Cytomorphological (chromosomes morphology and chromosome-banding) and meiotic pairing analyses confirmed the hybrid origin of 0. X gennarii. The 52 chromosomes plants showed somatic karyotypes with one set of 18 homomorphic pairs; additionally, 18 bivalents plus 16 univalents were prevalently observed in meiotic metaphase I. Possible pathways for the origin of the amphitriploid cytotype are discussed.

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Section: Discussionsupporting

confidence: 74%

Cytomorphological characterization of diploid and triploid individuals ofOrchis × gennariiReichenb. fil. (Orchidaceae)

D’Emerico¹,

Bianco²,

Pignone³

1996

Caryologia

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“…This allows the developmental phase of meiosis to be skipped and embryogenesis to occur precociously, resulting in apomictic or asexual development (Grimanelli et al 2001). This hypothesis is consistent with heterochronic effects are noted in Tripsacum (Grimanelli et al 2003) and apomeiosis produced by wide hybridization in wheat (Pignone 1993). The identification of differentially expressed or ''modified'' key sexual genes responsible for apomictic traits (apomeiosis and embryogenesis) remains elusive; however, genes such as MSP1 may provide an insight because mutation in this gene triggers the differentiation of nucellar cells into archeospores (Nonomura et al 2003).…”

Section: Discussionsupporting

confidence: 71%

Description of a fertilization-independent obligate apomictic species: Corunastylis apostasioides Fitzg

et al. 2009

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The Australian midge orchid Corunastylis apostasioides of the tribe Diurideae has completely eliminated any male contribution in the process of seed formation, which occurs directly from the maternal tissue by a process termed apomixis. Here, we report C. apostasioides to be an obligate apomictic species devoid of any sexuality and compare its development to a close sexual relative C. fimbriata (R. Br.) D.L. Jones & M.A. Clem. Apomictic characteristics in C. apostasioides include production of seed in absence of fertilization, frequently closed flowers, production of immature pollen in non-dehiscent anthers, expansion of ovaries despite the lack of fertilization and the absence of a citronella scent that is found in C. fimbriata produced to attract pollinating vinegar flies (Jones 2006). The nature of apomixis in C. apostasioides was examined by ovule histology and amplified fragment length polymorphism (AFLP) in each case drawing comparison with sexual C. fimbriata. In C. apostasioides the central megaspore mother cell undergoes diplosporic apomixis, while additional embryos are derived from nucellar or integument initials formed by sporophytic apomixis. Typical of apomicts, C. apostasioides is polyploid compared to the sexual C. fimbriata. The divergences of C. apostasioides from sexuality to apomictic development are discussed.

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“…In most interspecific and intergeneric crosses, the hybrids are almost completely sterile, and only very rarely a few seeds with doubled chromosome number are set spontaneously (Pignone, 1993), and the rareness of fertility in interspecific and intergeneric hybrids, which are almost always sterile, has been described extensively by Harlan and De Wet (1975). In the work presented here, spontaneous seed set did not occur, although Lange and Jochemsen (1992) found spontaneous doubling of chromosomes that gave rise to 13 seeds, from about 4600 florets, and in most cases as single seed per spike when they crossed T. turgidum ssp.…”

Section: Discussionmentioning

confidence: 99%

Assessment for salinity tolerance through intergeneric hybridisation: Triticum durum × Aegilops speltoides

Noori

2005

Euphytica

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Triploid hybrid embryos (AABB × SS = ABS) were produced by crossing two moderately salt-tolerant wheats, namely Triticum turgidum durum and Aegilops speltoides subsp. speltoides. The embryos were rescued by culturing on agar No. 1. Chromosome doubling was achieved by using 0.05% colchicine. The resulting hexaploid plants grew to maturity, and produced a considerable amount of seed (≈40,000). The synthetic hexaploid (C 2 ) was tested for salinity tolerance, grown at 0, 100, 125, 150, 160, 170, 180 and 200 mM NaCl in a standard nutrient solution for 2 weeks. The criterion of salt tolerance was root growth in different NaCl concentrations. The amphidiploid material showed greater salinity tolerance than either parent, suggesting the presence of different genes for tolerance in the parents.

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Non-reductional meiosis in aTriticum turgidum �Aegilops longissima hybrid and in backcrosses of its amphidiploid withT. turgidum (Poaceae)

Cited by 10 publications

References 13 publications

Cytomorphological characterization of diploid and triploid individuals ofOrchis × gennariiReichenb. fil. (Orchidaceae)

Cytomorphological characterization of diploid and triploid individuals ofOrchis × gennariiReichenb. fil. (Orchidaceae)

Description of a fertilization-independent obligate apomictic species: Corunastylis apostasioides Fitzg

Assessment for salinity tolerance through intergeneric hybridisation: Triticum durum × Aegilops speltoides

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