MEIOTIC STABILITY IN CONTROL AND NEWLY COLCHICINE-INDUCED DIHAPLOID BARLEY

R. A. Finch; M. D. Bennett

doi:10.1139/g79-005

MEIOTIC STABILITY IN CONTROL AND NEWLY COLCHICINE-INDUCED DIHAPLOID BARLEY

Canadian Journal of Genetics and Cytology ◽

10.1139/g79-005 ◽

1979 ◽

Vol 21 (1) ◽

pp. 33-35 ◽

Cited By ~ 5

Author(s):

R. A. Finch ◽

M. D. Bennett

Keyword(s):

Chromosome Number ◽

Breeding Material ◽

Two Generations ◽

Meiotic Stability

Comparison of meiosis in barley plants treated with colchicine when seedling or juvenile haploids and in control dihaploids similarly treated two generations earlier shows that colchicine used to double the chromosome number of barley haploids has no effect on meiosis which could lead to difficulties in screening breeding material.

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A marker chromosome number 14 with double satellite observed in two generations: An unbalanced chromosome constitution associated with normal phenotype

Human Genetics ◽

10.1007/bf00295748 ◽

1972 ◽

Vol 15 (2) ◽

pp. 191-195 ◽

Cited By ~ 1

Author(s):

F. Gigliani ◽

A. Capoa ◽

A. Rocchi

Keyword(s):

Chromosome Number ◽

Marker Chromosome ◽

Chromosome Constitution ◽

Normal Phenotype ◽

Two Generations

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Stability in chromosome number and DNA content in synthetic tetraploids of Lolium multiflorum after two generations of selection

Ciência Rural ◽

10.1590/0103-8478cr20150767 ◽

2017 ◽

Vol 47 (2) ◽

Cited By ~ 4

Author(s):

Roselaine Cristina Pereira ◽

Natália de Souza Santos ◽

Fernanda de Oliveira Bustamante ◽

Andrea Mittelmann ◽

Vânia Helena Techio

Keyword(s):

Chromosome Number ◽

Dna Content ◽

Genetic Stability ◽

Chromosome Doubling ◽

Lolium Multiflorum ◽

Colchicine Treatment ◽

Italian Ryegrass ◽

Chromosome Counting ◽

Two Generations ◽

Viable Seeds

ABSTRACT: Chromosome doubling of Italian ryegrass genotypes ( Lolium multiflorum Lam.) adapted to the brazilian edaphoclimatic conditions is an important strategy used by breeders and aims to obtain more vigorous genotypes with better forage quality and disease resistance. The effectiveness of chromosome doubling can be measured by genetic stability and fertility rates of plants over generations. However, a common problem in the polyploidization process is the regeneration of mixoploid plants that have impaired fertility and genetic stability. The objective of this study was to verify if progenies of recently tetraploidized plants remain stable regarding DNA content and chromosome number, over two generations. Progenies of L. multiflorum plants artificially tetraploidized with colchicine treatment were evaluated. Chromosome counting and estimates of the DNA content were used to evaluate the genetic stability. The percentage of tetraploid plants (4X) increased over generations (18%, 34% and 91% in cycle 0, 1 and 2, respectively). All progenies identified as tetraploid by flow citometry showed variation in chromosome number (mixoploidy), but produced viable seeds. Results showed that stabilization in chromosome number and DNA content in tetraploidized plant progenies requires time and that the success of this procedure depends on a continuous and accurate screening and selection.

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Yield improvement of oilseed rape (Brassica napus L.) in a low rainfall environment. I. Utilization of genes for early flowering in primary and secondary gene pools

Australian Journal of Agricultural Research ◽

10.1071/ar9920609 ◽

1992 ◽

Vol 43 (3) ◽

pp. 609 ◽

Cited By ~ 3

Author(s):

N Thurling ◽

R Kaveeta

Keyword(s):

Brassica Napus ◽

Chromosome Number ◽

Flowering Time ◽

Chromosome Complement ◽

Early Flowering ◽

Gene Pools ◽

Yield Improvement ◽

Two Generations ◽

The Cross ◽

Recurrent Backcrossing

The extent to which time to flowering of a Brassica napus commercial cultivar could be reduced through utilization of genes in its primary and secondary pools was examined with particular reference to yield improvement in lower rainfall environments. The B. napus breeding line RU2 and the B. campestris population Chinoli C42, which were used as sources of early flowering genes to be incorporated into the commercial B. napus cultivar Wesbrook, flowered significantly earlier than Wesbrook with or without vernalization and/or long days. In the cross of Wesbrook with RU2, the substantial variation in flowering time in the F2 was highly heritable (hn2 = 0.79), and some plants in the F2 and first backcross to Wesbrook flowered earlier than the early flowering parent RU2. Many lines flowering much earlier than Wesbrook were still obtained after two generations of recurrent backcrossing to Wesbrook and subsequent selfing without selection at any stage. Variation in flowering time among these lines primarily reflected differences in growth rate as measured by the rate of leaf node development. F2 plants derived from the cross between Wesbrook and the B. campestris population Chinoli C42 varied widely in chromosome number and flowering time, but there was no relationship between pre-anthesis development and chromosome number. Two generations of recurrent backcrossing to Wesbrook and subsequent selfing without selection at any stage produced a series of lines all having the normal B. napus chromosome complement. All these lines flowered significantly earlier than Wesbrook, and the earliest flowering line flowered at the same time as the early flowering B. campestris parent. The implications of these results are discussed with particular reference to developing agronomically superior B. napus cultivars closely adapted to lower rainfall environments in the Western Australian wheatbelt and elsewhere in southern Australia.

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Chromosome number and microsporogenesis of two accessions of Brachiaria dura Stapf (Poaceae)

Biota Neotropica ◽

10.1590/s1676-06032009000200024 ◽

2009 ◽

Vol 9 (2) ◽

pp. 257-261 ◽

Cited By ~ 6

Author(s):

Claudiceia Risso-Pascotto ◽

Maria Suely Pagliarini ◽

Cacilda Borges do Valle

Keyword(s):

Chromosome Number ◽

Chromosome Doubling ◽

Low Frequency ◽

Chromosome Association ◽

Meiotic Abnormalities ◽

Entire Genome ◽

Chromosome Transfer ◽

Meiotic Stability

The two accessions of B. dura analyzed (DU01 and DU02) are hexaploid (2n = 6x = 54), derived from x = 9. Meiotic abnormalities, such as precocious chromosome migration to the poles, laggards and micronuclei, were recorded in low frequency in both accessions. The few multivalent chromosome association at diakinesis and meiotic stability suggested that hexaploidy probably resulted from chromosome doubling. In DU02, chromosome transfer (cytomixis) among meiocytes, involving part or the entire genome was observed. The implication of these findings for the Brachiaria breeding is discussed.

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