A CYTOLOGICAL SURVEY OF ZEA-TRIPSACUM HYBRIDS

1973 ◽  
Vol 15 (4) ◽  
pp. 763-778 ◽  
Author(s):  
C. A. Newell ◽  
J. M. J. de Wet
Keyword(s):  
Zea Mays ◽  
Chromosome Number ◽  
Zea Mays L ◽  
Homologous Pairing ◽  
Tripsacum Dactyloides ◽  
Chromosome Behavior ◽  
Chromosomal Homology ◽  
Cytological Data ◽  
Chromosomal Association ◽  
Bivalent Formation

Reciprocal crosses involving various combinations of diploid (2n = 20) and tetraploid (2n = 40) Zea mays L. (maize), diploid (2n = 20) Zea mexicana (Schrad.) Kuntze (annual teosinte), and tetraploid (2n = 40) Zea perennis (Hitchc.) Reeves and Mangelsdorf (perennial teosinte) were studied cytologically. Observations of chromosome behavior during meiosis indicated that chromosomes of Z. perennis were more compatible with those of Zea mays than with those of Z. mexicana. Hybrids between Z. mays and diploid (2n = 36) or tetraploid (2n = 72) Tripsacum dactyloides (L.) L, incorporating different numbers of genomes from each parent and ranging in chromosome number from 2n = 28 28 to 2n = 82, were also examined at meiosis. Allodiploids (2n = 28) combining one Zea genome with one Tripsacum genome showed a low level of synaptic bivalent formation, indicating limited chromosomal homology between the two genera. Almost without exception, maize-Tripsacum hybrids exhibited more chromosomal association than expected on the basis of strictly homologous pairing; however, only a few plants possessed configurations stable enough to be taken as evidence of possible intergeneric segmental exchange. Triple hybrids involving maize, teosinte, and Tripsacum were produced in several combinations by pollinating maize-Tripsacum hybrids with annual or perennial teosinte. These showed chromosomal associations in accordance with the expected, on the basis of cytological data from maize-Tripsacum and maize-teosinte hybrids. These cytological observations suggest that teosinte and maize are conspecific, and that teosinte could not have originated as a by-product of Zea-Tripsacum introgression.

NULLISOMIC ANALYSIS OF NUCLEOLAR FORMATION IN ZEA MAYS

1978 ◽  
Vol 20 (1) ◽  
pp. 97-100 ◽  
Author(s):  
David F. Weber
Keyword(s):  
Zea Mays ◽  
Chromosome Number ◽  
Zea Mays L ◽  
Diploid Species ◽  
5S Rrna ◽  
Chromosome 6 ◽  
Chromosome 2 ◽  
Nucleolar Organizing Region

When a monosomic plant of a diploid species undergoes meiosis, two haploid and two nullisomic cells are produced. Zea mays L. microspore quartet cells nullisomic for chromosome number 1, 2, 4, 6, 7, 8, 9, or 10 produced by monosomics were analyzed. Cells nullisomic for chromosome 6, as expected, do not contain a nucleolus because chromosome 6 bears the nucleolar organizing region. Cells nullisomic for chromosome 2 contain nucleoli; therefore, the 5S rRNA template on chromosome 2 is not necessary for nucleolar formation. Cells nullisomic for chromosomes 1, 4, 7, 8, 9, or 10 also contain nucleoli; thus, no factors located on these chromosomes are necessary for nulceolar formation at the quartet stage.

Adjacent II segregation products in B–A translocations of maize

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 595-602 ◽  
Author(s):  
B. Kindiger ◽  
C. Curtis ◽  
J. B. Beckett
Keyword(s):  
Zea Mays ◽  
Key Words ◽  
Zea Mays L ◽  
Genetic Data ◽  
B Chromosomes ◽  
Cytological Data ◽  
Opposite Pole

In maize (Zea mays L.), meiotic events in B–A translocations that cause the A chromosome to move to one pole and the A–B and B–A chromosomes to move to the opposite pole result in the production of balanced, functional microspores and megaspores. Meiotic events that allow other combinations of chromosomes to proceed to the two poles (A A–B and A B–A) lead to the production of both duplicate (A A–B) and deficient (B–A) spores. Microspores and often megaspores that are deficient for a segment of the A chromosome are expected to abort. Duplication-bearing gametes usually function through the egg but are less able to compete with the normal gametes in the pollen. Cytological data, and genetic data from pollen, kernel, and seedling counts, were used to identify the production of A A–B gametes by B–A translocation heterozygotes and hyperploids. Adjacent II segregation of the A and A–B chromosomes of B–A heterozygotes and hyperploids has been detected in stocks of several different B–A translocations. Some B–A translocations exhibited a frequency of adjacent II segregation as high as 23%.Key words: Zea mays, adjacent segregation, B chromosomes, translocation.

scholarly journals NaCl effects in Zea mays L. x Tripsacum dactyloides (L.) L. hybrid calli and plants

2006 ◽  
Vol 9 (3) ◽  
pp. 0-0 ◽  
Author(s):  
Julieta Pesqueira ◽  
Maria Dina Garcia ◽  
Sebastian Staltari ◽  
Maria del Carmen Molina
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Tripsacum Dactyloides

scholarly journals Assessment of the potential for gene flow from transgenic maize (Zea mays L.) to eastern gamagrass (Tripsacum dactyloides L.)

2017 ◽  
Vol 26 (4) ◽  
pp. 501-514 ◽  
Author(s):  
Moon-Sub Lee ◽  
Eric K. Anderson ◽  
Duška Stojšin ◽  
Marc A. McPherson ◽  
Baltazar Baltazar ◽  
...  
Keyword(s):  
Zea Mays ◽  
Gene Flow ◽  
Zea Mays L ◽  
Transgenic Maize ◽  
Tripsacum Dactyloides ◽  
Eastern Gamagrass

scholarly journals Tripsazea, a Novel Trihybrid of Zea mays, Tripsacum dactyloides, and Zeaperennis

2019 ◽  
Vol 10 (2) ◽  
pp. 839-848
Author(s):  
Xu Yan ◽  
Mingjun Cheng ◽  
Yingzheng Li ◽  
Zizhou Wu ◽  
Yang Li ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Zea Mays ◽  
Chromosome Number ◽  
Dna Sequence ◽  
Flow Cytometry Analysis ◽  
Seed Setting ◽  
Tripsacum Dactyloides ◽  
Male Sterile ◽  
Phenotypic Characteristics ◽  
Seed Setting Rate

A trispecific hybrid, MTP (hereafter called tripsazea), was developed from intergeneric crosses involving tetraploid Zea mays (2n = 4x = 40, genome: MMMM), tetraploid Tripsacum dactyloides (2n = 4x = 72, TTTT), and tetraploid Z. perennis (2n = 4x = 40, PPPP). On crossing maize-Tripsacum (2n = 4x = 56, MMTT) with Z. perennis, 37 progenies with varying chromosome numbers (36-74) were obtained, and a special one (i.e., tripsazea) possessing 2n = 74 chromosomes was generated. Tripsazea is perennial and expresses phenotypic characteristics affected by its progenitor parent. Flow cytometry analysis of tripsazea and its parents showed that tripsazea underwent DNA sequence elimination during allohexaploidization. Of all the chromosomes in diakinesis I, 18.42% participated in heterogenetic pairing, including 16.43% between the M- and P-genomes, 1.59% between the M- and T-genomes, and 0.39% in T- and P-genome pairing. Tripsazea is male sterile and partly female fertile. In comparison with previously synthesized trihybrids containing maize, Tripsacum and teosinte, tripsazea has a higher chromosome number, higher seed setting rate, and vegetative propagation ability of stand and stem. However, few trihybrids possess these valuable traits at the same time. The potential of tripsazea is discussed with respect to the deployment of the genetic bridge for maize improvement and forage breeding.

scholarly journals Karyotypic diversity among eight Zea mays L. varieties

2020 ◽  
Vol 49 (4) ◽  
pp. 1157-1161
Author(s):  
Chandan Kumar Dash ◽  
Kazi Nahida Begum ◽  
Syeda Sharmeen Sultana
Keyword(s):  
Zea Mays ◽  
Chromosome Number ◽  
Significant Variation ◽  
Zea Mays L ◽  
Chromosome Length ◽  
Diploid Chromosome Number ◽  
Genetic Identification ◽  
Interphase Nuclei ◽  
Maize Varieties ◽  
Karyotypic Diversity

Staining property of interphase nuclei and prophase chromosomes, diploid chromosome number, total chromosome length (TCL), symmetric and asymmetric indices of karyotype were studied in eight maize varieties released by BARI. 2n = 20 chromosomes were found in Barnali, Mohor, Khoi Vhutta, BS-1, B-5 and BM-7 whereas 2n = 22 chromosomes in China and 2n = 24 chromosomes in B-73 were observed. TCL was highest in Mohor (190.49 ± 5.61 μm) and lowest in B-73 (69.30 ± 2.51 μm). These varieties showed significant variation in cytogenetical parameters. Results obtained are expected to supplement genetic identification of maize varieties in variety conservation efforts.

Sign in / Sign up

Export Citation Format

Share Document