caa a22 4500 477134122 CHVBK 20180405111712.0 cr unu---uuuuu 170330e19970201xx s 000 0 eng 10.1023/A:1002914808150 doi (NATIONALLICENCE)springer-10.1023/A:1002914808150 The causes and consequences of meiotic irregularity in the leek (Allium ampeloprasum spp. porrum); implications for fertility, quality and uniformity [Elektronische Daten] [K.A. Khazanehdari, G.H. Jones] 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. Kluwer Academic Publishers, 1997 leek nationallicence Allium ampeloprasum spp. porrum nationallicence meiosis nationallicence aneuploidy nationallicence uniformity nationallicence fertility nationallicence Khazanehdari K.A. School of Biological Sciences, The University of Birmingham, B15 2TT, Edgbaston, Birmingham, United Kingdom aut Jones G.H. School of Biological Sciences, The University of Birmingham, B15 2TT, Edgbaston, Birmingham, United Kingdom aut Euphytica Kluwer Academic Publishers 93/3(1997-02-01), 313-319 0014-2336 93:3<313 1997 93 10681 https://doi.org/10.1023/A:1002914808150 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1002914808150 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Khazanehdari K.A. School of Biological Sciences, The University of Birmingham, B15 2TT, Edgbaston, Birmingham, United Kingdom aut NATIONALLICENCE 700 1- Jones G.H. School of Biological Sciences, The University of Birmingham, B15 2TT, Edgbaston, Birmingham, United Kingdom aut NATIONALLICENCE 773 0- Euphytica Kluwer Academic Publishers 93/3(1997-02-01), 313-319 0014-2336 93:3<313 1997 93 10681 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer