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Wheat Information
Service
Number 73: 36-39 (1991)
Location
of genes for awnedness and waxiness using monosomic analysis in wheat
(Triticum aestivum)*
0. Sridevi, J. V. Goud and K. V. Bhat**
Division of Genetics and Plant Breeding University of
Agricultural Sciences. Dharwad-5, Karnataka, India
Several varieties of common wheat (Triticum aestivum L.) and
of other species are waxy on various parts of the plants, e.g.,
leaves, leaf sheaths, glume surface etc. The genotypes are classified
based on this into waxy and non-waxy.
The awn is the extension of flowering glume. Wheats have been
classified as awned and awnless. Monosomic analysis has revealed that
awning in bread wheat is controlled by a series of awn promoter genes
and three major epistatic genes 'Hd', on chromosome VIII (4B),
B1 on IX (5A) and B2 on X (6B). A series of 'A'
genes have been proposed by Heyne and Livers (1953) to explain awn
development in different varieties. An 'A' gene is
hypothetically non-epistatic but incompletely dominant over an awn
producing 'a' allele. A single locus in the homozygous
recessive condition 'aa' could produce full awns, if not
inhibited by partially epistalic Hd or B1 or B2.
The present study was aimed at identifying the chromosomes associated
with the genes influencing these traits by using all the twentyone
monosomic lines of variety Kalyansona.
Materials and Methods
Twentyone monosomic lines of Kalyansona were crossed with DWR-39
and in F1, confirmed monosomic plants were carried to
F2 generation. Segregation for waxiness, i.e., waxy and
nonwaxy types and for awn character viz., fully awned, sparsely
awned, hooded and awnless was observed.
In the same manner, normal disomic cross was made using both the
parents and forwarded to F2 generation and observations
made in disomic F2 were compared with those of monosomic
F2 populations.
*Part of the M. Sc Thesis
submitted by the first author to University of Agricultural Sciences,
Dharwad-580005.
**Present Address --
NBPGR, IARI, New Delhi- 110 012.
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