Somatic Instability in the Brazilian Semi-Dwarf Wheat Ias 54

Abstract

The mitotic chromosome behavior of the Brazilian semi-dwarf wheat cultivar IAS 54 (Triticum aastivum L. em Tell) is described. In root tip cells dicentrics, fragments, isochromosomes, a satellite tandemly duplicated, chromatid exchanges, aneuploidy, ring chromosomes and breaks in almost all chromosomes of the complement were observed. Since anaphase cells that were not pretreated showed bridges, disorderly condensation and micronwlei, the possibility that pretreatment was responsible for the abnormalities was eliminated. Other possible genetic factors and virus infection as causal agents were discussed. Ees travaux ont p o d sur le comportement des chromosomes mitotiques du cultivar du bl6 brisilien semi-nain IAS 54 (Triticum aestivum E. em Tell). Dans les cellules h I'extrCmitC des racines on a observt des dicentriques, des fragments, des isochromosomes, un satellite dsublC en tandem, des Cchanges chromatidiques, l'aneuploi'die, Qes chromosomes en anneaux, et des bris dans presque tous les chromosomes de la garniture chromosomique. On a Climint au depart Ia possibilitC que le prktraitement soit responsable des anomalies, itant donnC que les cellules anaphasiques non-traitkes manifestaient aussi des ponts, une condensation disordonnie et des micronoyaux. On discute d'autres muses possibles, soit d'autres facteurs d'ordre ghiitique, et I'infection vbale. [Traduit par le journal] "C&UUQ Especid de Pbs-Grrmdimgiio e Pesqmrfsa da Universidade Federal do Rio G r a d e do Sul". Work of the senior author was done in partial fulfiment of the M.S. degee at the Federal University of Rio Grtmde do Sul. wesent address: Pemmbuco. Reprints should be requested to M. heme M. Femmdes, C.N.P. Trigo-EMBRAPA cx Psstal569, 99. 100 RUSQ Fundo RS-Br.

Molecular cytogenetic characterization of parental genomes in the partial amphidiploid Triticum aestivum x Thinopyrum ponticum

“…Brasileiro-Vidal (2003) observed that this mitotic instability was already present in the cultivar used as recurrent wheat parent ('CEP 19'). The same phenomenon was previously reported for other Brazilian wheat cultivars (Guerra and Moraes-Fernandes, 1977), and it was probably enhanced by the hybrid condition. Influence of the parental genotypes on chromosome elimination has also been observed in wide-cross hybrids, and differential elimination seems to be dependent on the ordered spatial arrangement of chromosomes throughout the cell cycle (see Heslop-Harrison and Schwarzacher, 1993).…”

Effect of mass selection for seed density in populations derived from Avena abyssinica x A. sativa amphidecaploids

“…Lastly, endogenous nucleases may be responsible for chromosome degradation (Subrahmanyam & Kasha, 1973 ;Lavania, 1982) . The mechanisms underlying these phenomena are probably under genetic control (Sachs, 1954 ;Watanabe, 1962 ;Guerra & Fernandes, 1977 ;Lavania, 1982) .…”

Chromosomal instability in lemon grass, Cymbopogon flexuosus (Steudel) Wats

“…Chromosomal instability without clear correlation with plant morphology has been recorded in other plant species also: Larix (Illies, 1966), Medicago (Sadasivaiah & Lesins, 1974), Wheat (Watanabe, 1962;Guerra & Fernandes, 1977), Bromus inermis (Tan & Dunn, 1977), tobacco (Ogura, 1978), Lathyrus sativus (Lavania, 1982), Coix gigantia (Nirmala & Rao, 1984), and many others cited therein. Chromosomal instability without clear correlation with plant morphology has been recorded in other plant species also: Larix (Illies, 1966), Medicago (Sadasivaiah & Lesins, 1974), Wheat (Watanabe, 1962;Guerra & Fernandes, 1977), Bromus inermis (Tan & Dunn, 1977), tobacco (Ogura, 1978), Lathyrus sativus (Lavania, 1982), Coix gigantia (Nirmala & Rao, 1984), and many others cited therein.…”

“…Variability in chromosome number and morphology is more common in somatic cells cultured in vitro (Bayliss, 1980;Larkin & Scowcroft, 1981). It has been established in such important crop plants as wheat, tobacco and trees like larches, that this chromosome chimerism and elimination in chromosome number may be genetically controlled in certain biotypes (Illies, 1966;Guerra & Fernandes, 1977;Ogura, 1978), although not in all cases reported the observations are entirely reliable. It has been established in such important crop plants as wheat, tobacco and trees like larches, that this chromosome chimerism and elimination in chromosome number may be genetically controlled in certain biotypes (Illies, 1966;Guerra & Fernandes, 1977;Ogura, 1978), although not in all cases reported the observations are entirely reliable.…”