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Results and
Discussion
The values in Table
1 reveal that
plants in 17 monosomic F2 populations segregated into
different types whereas in disomic F2 cross there was no
segregation. This difference in awning seemed to be controlled by
factors located on at least seventeen chromosomes. Similar situation
was observed in the report on tetraploid wheat Khapli by Mokhtarzadeh
(1975) where he explained that awning is controlled by factors
located on nine chromosomes. Similar type of explanation was given to
describe the inheritance of glume colour in Red Bobs (Sadananda,
1977), in Cadet (Bhowal and Jha, 1969) and in Khapli (Mokhtazadeh,
1975).
This indicates that there is a complex interaction among genes
present on these seventeen chromosomes with the genotype of the male
gamete when the genes are present in hemizygous condition (single
dose). This is the reason why segregation was not observed in four
populations where these seventeen chromosomes are present in
homozygous condition. Depending on the type of interaction the gene
is engaged in, the ultimate rations in the critical families are
bound to vary. That is why the segration ratio differed among the
critical families or it may be due to the modifying factors, which
affect the expression of main factors, A, B and Hd
(Clark, 1926).
For waxiness also, segregation into waxy and nonwaxy was not
observed in disomic, F2 population (Table
2). But seventeen
monosomic populations showed segregation, the remaining four viz.,
4A, 6A, 5D and 7D did not, thus, indicating the presence of genes for
waxiness on these seventeen chromosomes and simultaneous absence of
segregation for the two characters, i.e., waxiness and awnedness in
four populations. From this we can infer that these two genes
affecting awnedness and waxiness are closely associated or may be
that there is pleiotropic effect of the concerned genes on these two
characters.
References
Bhowal JG and Jha MP (1969) An inhibitor of glume pigment in
wheat. Can J Genet Cytol 11: 226.
Clark JA (1926) Segregation and correlated inheritance in Marquis and
Hard Federation Crosses, with factors for yield and quality of spring
wheat in Montana. U. S. Dept Ag Bull 1403.
Heyne EG and Livers RW (1953) Monosomic analysis of leaf rust
reaction, awnedness, winter injury and seed colour in Pawnee wheat.
Agron J 45: 54-58.
Mokhtarzadh A (1975) Utilization of F1 monosomics for
genetic analysis involving awn expression, glume colour, seed setting
and seed abortion in crosses of tetraploid and hexaploid wheats.
Theor Appl Genet 46: 1-5.
Sadananda AR (1977) Cytogenetic investigations of some morphological
and grain characters in hexaploid wheat (Triticum aestivum L.
) using F2 monosomic analysis. M. Sc. Thesis, University
of Agricultural Sciences, Bangalore.
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