Abstract
We have previously confirmed that Allium ampeloprasum spp. porrum, the leek, shows extensive and frequent quadrivalent formation during prophase I of meiosis, and that despite the resolution of most of these into bivalents some quadrivalents persist to metaphase I; in addition, a substantial number of univalents are found at this stage. In this paper we examine the later meiotic and post meiotic consequences of these irregularities in four leek cultivars and discuss their implications. Irregularities of chromosome segregation are observed at anaphase of both meiotic divisions, giving rise to micronuclei in dyad and tetrad stage pollen mother cells. It is shown that micronucleus frequency in tetrads is correlated with univalent frequency at metaphase I, suggesting that micronuclei originate largely from missegregation of univalents. Seedling populations of the same four cultivars were screened cytologically and shown to contain aneuploids at frequencies ranging between 4.3% and 8.4%. It is proposed that the majority of aneuploid seedlings originate from meiotic irregularity, especially univalent missegregation. It is very likely that the presence of this level of aneuploidy in the seedling populations contributes to the problems of phenotypic non-uniformity experienced by the leek crop, although its relative importance is difficult to assess. Further studies are required to establish the genetical and environmental contributions to meiotic irregularity and to assess the potential for selection for greater meiotic regularity in this material.
Similar content being viewed by others
References
Baker, B.S., A.T.C. Carpenter, M.S. Esposito, R.E. Esposito & L. Sandler, 1976. The genetic control of meiosis. Annu Rev Genet 10: 53–134.
Baumunk-Wende, E., 1989. Application of tissue culture in leek breeding (Allium porrum L.). Gartenbauwissenschaft 54: 20–24.
Berninger, E. & P. Buret, 1967. Etude des déficients chlorophylliens chez deux espèces cultivées du genre Allim: L'oignon A. cepa L. et le poireau A. porrum L. Annales de L'amélioration des Plantes 17: 175–194.
Buiteveld, J., P. van der Valk, J. Jansen, J. Creemers-Molenaar & C.M. Colijn-Hooymans. Callus induction and plant-regeneration from explants of commercial cultivars of leek (Allium ampeloprasum L.). Plant Cell Reports 12: 431–434.
Currah, L., 1986. Leek breeding — a review. J Hort Sci 61: 407–415.
Evans, G.M., 1981. Polyploidy and crop improvement. J Agri Soc Univ Coll Wales 62: 93–116.
Gohil, R.N. & A.K. Koul, 1977. The cause of multivalent suppression in Allium ampeloprasum L. Beitr Biol Pflanzen 53: 473–478.
Gray, D. & J.R.A. Steckel, 1986a. Self and open-pollination as factors influencing seed quality in leek (Allium porrum). Ann Appl Biol 108: 167–170.
Gray, D. & J.R.A. Steckel, 1986b. The effects of seed crop plant density, transplant size, harvest date and seed grading on leek (Allium porrum L.) seed quality. J Hort Sci 61: 315–323.
Gray, D., W.G. Tucker, L.J. Hands & J.R.A. Steckel, 1989. Some effects of drying leek (Allium porrum) seeds harvested at different stages of maturity on seed and seedling performance. J Hort Sci 64: 455–465.
Gray, D. & J.A. Ward, 1987. A comparison of leek (Allium porrum) and onion (Allium cepa) seed development. Ann Bot 60: 181–197.
Jones, G.H., K.A. Khazanehdari & B.V. Ford-Lloyd, 1996. Meiosis in Allium porrum L. (the leek) revisited. II Metaphase I observations. Heredity 76: 186–191.
Kadry, A.E.R. & S.A. Kamel. 1995. Cytological studies in the two tetraploid species of Allium kurrat Schweinf. and Allium porrum L. and their hybrid. Sven Bot Tidskr 49: 314–324.
Khazanehdari, K.A., 1995. Meiotic chromosome behaviour and somatic chromosome variation in the leek (Allium porrum L.). PhD thesis, University of Birmingham.
Khazanehdari, K.A., G.H. Jones & B.V. Ford-Lloyd, 1995. Meiosis in Allium porrum L. (the leek) revisited I. Prophase I pairing. Chromosome Res 3: 433–439.
Khush, G.S., 1973. Cytogenetics of Aneuploids. Academic Press, London and New York.
Koul, A.K. & R.N. Gohil, 1970. Cytology of the tetraploid Allium ampeloprasum with chiasma localization. Chromosoma 29: 12–19.
Levan, A., 1940. Meiosis of Allium porrum, a tetraploid species with chiasma localization. Hereditas 26: 454–462.
Rees, H., 1961. Genotypic control of chromosome form and behaviour. Bot Rev 27: 288–318.
Sybenga, J., 1975. Meiotic configurations. In: R. Frankel (Ed.) Monographs on Theoretical and Applied Genetics. Springer-Verlag, Berlin and New York.
Schweisguth, B., 1970. Etudes preliminaires a l'amélioration du Poireau A. porrum L. Proposition d'une méthode d'amélioration. Annales de L'amélioration des Plantes 22: 215–231.
Smith, B. & T.C. Crowther, 1995. Inbreeding depression and single cross hybrids in leeks (Allium ampeloprasum ssp. porrum). Euphytica 86: 87–94.
Vilmorin-Andrieux, M.M., 1885. The Vegetable Garden. John Murray, London.
Wajahatulla, M.K., 1994. The behaviour of meiotic chromosomes in leek, A. porrum L. Cytologia 59: 333–338.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Khazanehdari, K., Jones, G. The causes and consequences of meiotic irregularity in the leek (Allium ampeloprasum spp. porrum); implications for fertility, quality and uniformity. Euphytica 93, 313–319 (1997). https://doi.org/10.1023/A:1002914808150
Issue Date:
DOI: https://doi.org/10.1023/A:1002914808150