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KALTSIKES et al. (1968) identified a segment of
the long arm of 'Prelude' 1D which conditioned the good
bread-making quality of this cultivar. However, MAYSTRENKO
et al. (1973a) concluded that, in Chinese Spring,
genes enhancing flour quality were present on the short arm
of 1D because its absence gave very poor physical properties
of the dough.
In view of the important role of chromosome 1D in
determining the flour characteristics of hexaploid wheats,
it is not surprising that this chromosome has considerable
genetic control over the aspects of protein composition that
influence bread quality, namely, gluten and its principal
components, gliadin and glutenin. 1D contributes genes for
gluten quality (MAYSTRENKO et al. 1973b, SASAKI et
al. 1973) and for components of glutenin (JOPPA et
al. 1975) and gliadin (SOLARI and FAVRET 1970, KONAREV
et al. 1972, WRIGLEY and SHEPHERD 1973, KASARDA et
al. 1974). The short arm influences gluten composition
(BOYD and LEE 1967, KHRABROVA et al. 1973) and
gliadin components (SHEPHERD 1968) . The long arm controls
certain glutenin subunits (ORTH and BUSHUK 1974, BIETZ et
al. 1975). Most of the studies on protein composition
have tested chromosome 1D of Chinese Spring, which has poor
dough-handling and baking properties. Chromosome 1D from
some of the best bread cultivars should be tested in similar
studies.
Identity tests of the "1D' line in the monosomic state
indicated that 1A instead of 1D was the substituted
chromosome. However, the disomic state of this line had much
poorer mixing and loaf characteristics than the substitution
line developed for 1A. Probably a univalent shift occurred
from 1D to 1A during the development of the "1D" line. In
that case, both 1A in monosomic state and 1D in disomic
state could have a mixture of genes from Cheyenne and
Chinese Spring. The inferior performance of the line could
be due to interactions of genes from the two parental
cultivars or to unfavorable cytogenetic conditions of 1A or
1D. One exmaple of the latter might be a deficiency for a
segment of 1D that contains essential genes for flour
quality.
Summary
The 1D chromosome pair from the strong-gluten wheat cultivar
Cheyenne was substituted for the homologous chromosome pair
in the weak-gluten cultivar Chinese Spring by a series of
six backcrosses after the initial cross. Dough-mixing tests
demonstrated that the increased mixing time and tolerance of
Cheyenne, in contrast to Chinese Spring, were controlled at
least partially by a major gene(s) on chromosome 1D of
Cheyenne. Another substitution line, which might involve the
substitution of segments of Cheyenne chromosomes 1A and 1D
(the so-called "1D" line), was inferior to Chinese Spring in
mixing time and tolerance.
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