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Number 78: 13-17 (1994)
II.
Articles
Intervarietal polymorphism of heterochromatin in bread wheat,
Triticum aestivum L.
Ahsan A. Vahidy, Qamar Jahan and A. Mujeeb-Kazi1
Department of Genetics, University of Karachi, Karachi-75270,
Pakistan
Summary
Polymorphism in banding patterns of somatic chromosomes in
Triticum aestivum L. cultivars, Jauhar, M-143, Pavon,
Sarsabz, Sindh-81, Mexipak, Sonalika, ZA-77 and Chinese Spring was
studied by the Giemsa N-banding technique. Sixteen out of twenty one
chromosomes exhibited distinct banding patterns, while no bands were
observed in 1A and 3D to 6D. The banding polymorphism was observed
mainly in the B-genome chromosomes, whereas the D-genome chromosomes
revealed maximum consistency. The bands 1BL2.7 and 6BL2.5 reported by
earlier workers in Chinese Spring were not observed in our material
of the same cultivar, which however, showed the maximum number of
bands per haploid genome. Thirteen of these bands were missing in
different combinations in other cultivars. Four bands viz., 2BL2.41,
3BL2.41, 7BL2.61 and 2DL1.7 not present in the cv. Chinese Spring,
were observed in M-143, Sarsabz, Mexipak; Jauhar, M-143, Pavon,
Sarsabz; M-143, Sindh-81, Sarsabz, Mexipak; and Sindh-81,
respecitively. On the basis of the banding pattern an homozygous
reciprocal translocation involving 5A and 4B chromosomes was observed
in a plant belonging to cv. M-143. This led to the formation of
5AL/4BL and 5AS/4BS instead of normal 5A and 4B chromosomes.
Introduction
The N-banding technique has been shown to stain specific
heterochromatic regions in many organisms, including cereal crops,
such as barley (Islam 1980, Singh and Tsuchiya 1982), rye (Schlegel
and Gill 1984) and wheat (Endo and Gill 1983, Gill 1987, Gerlach
1977). It has been employed for detecting translocations between
wheat and barley chromosomes, for isolating lines possessing a pair
of barley chromosomes substituted for a particular pair of wheat
chromosomes (Islam 1980), and for detecting the 1B/1R translocation
in many cultivars of wheat (Cai and Liu 1989, Jahan et al. 1990).
The aim of the present study was to explore the extent of band
heteromorphy and chromosome polymorphism in several Pakistani wheat
cultivars as compared to the check cultivar, Chinese Spring,
utilizing Giemsa N-banding technique, and standard chromosome band
nomenclature.
1 Intemational Maize and Wheat Improvement Center
(CIMMYT), Lisboa 27, Apartado Postal 6-641 Delegacion Cuauhtemoc
06600, Mexico, D.F. Mexico.
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