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Wheat Information
Service
Number 77: 19 - 22 (1993)
Detection of Quadrivalents in the Brazilian wheat
'Frondoso'
William A. Berzonsky
Agronomy Dept., Ohio Agricultural Research and Development
Center, The Ohio State University, Wooster, OH 44691, USA
Translocations have been detected in many wheat (Triticum
aestivum L.) cultivars in comparison to the chromosome standard,
'Chinese Spring' (Baier et al. 1974; Vega and Lacadena 1982; Lange et
al.1987). Heterozygous reciprocal translocations might persist in
wheat cultivars, even after generations of self-pollination, due to
the compensation for deficient genes by genes on homoeologous
chromosomes.
Primard et al. (1991) identified quadrivalents in the wheat cultivar
'Atlas 66' due to a heterozygous reciprocal translocation involving
chromosome arms 2AL and 2DL. They indicated that the translocation
had persisted through seven generations of self-pollination and that
its origin was unknown.
Atlas 66 was developed in North Carolina, USA from the
cross'Frondoso'//'Redhart 3'/'Noll 28'(Heyne 1958). Frondoso
originated from Brazil (USDA, ARS, Germplasm Resources Information
Network, Beltsville, Maryland, USA). Love (1951) examined 19
Brazilian wheat cultivars for meiotic instabilities. One of these
cultivars, 'Frontana', a cultivar with the same pedigree as Frondoso,
had an abnormal meiosis characterized by failure of pairing and
lagging of bivalents at disjunction.
The purpose of this study was to examine the meiosis of Frondoso for
quadrivalents. The existence of quadrivalents was hypothesized based
on Frondoso's Brazilian origin, its use as a parent in the
development of Atlas 66, and the prior identification of
quadrivalents in Atlas 66.
Materials and methods
Seed of Frondoso was obtained from the USDA National Small Grains
Collection. Frondoso is a red spring wheat cultivar developed from
the cross 'Fronteira'/'Mentana' (USDA, ARS, Germplasm Resources
Information Network, Beltsville, Maryland, USA).
Anthers, with pollen mother cells (PMCs) at metaphase I, were
identified in temporary acetocarmine smears (Darlington and Lacour
1950) and fixed in a 3:1, 95% alcohol:glacial acetic acid mixture.
Anthers, collected from 10 different plants grown in a glasshouse,
were hydrolyzed in 1N HCI for 12 min, stained with Feulgen
(Darlington and LaCour 1950), and smeared in propionic orcein. Slides
were made permanent by mounting a coverslip with Canada Balsam after
passing them through a 50:50, 100% tertiary butyl alcohol
(TBA):glacial acetic acid mixture and two changes of 100% TBA.
Meiotic observations were made for 20 well-spread, complete cells
from each plant sampled and configurations were recorded following
the nomenclature of Kimber and Sears (1968).
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