ITEMS FROM BULGARIA
INSTITUTE FOR PLANT GENETIC RESOURCES
4122 Sadovo, Plovdiv, Bulgaria.
Winter wheat breeding.
D. Boyadjieva, A. Dimov, P. Stancova, V. Vasilev, M. Mangova, and Hr. Philipov.
The most recent bread wheat cultivar `Sadovo
552' was accepted at the 50th meeting of the Bulgarian
State Cultivar Commission in March 1995. Sadovo 552 was created
at the IPGR, Sadovo, from the hybrid `Mironovska 15/H10'.
The cultivar is of the medium-early type, with remarkably high
cold and drought resistance. The stem is about 100-110
cm, with good lodging resistance. The spike is dense, with an
underlined resistance to shattering during and after maturity.
The grain is large with a 1,000-kernel weight of about 40 g, or
up to 50 g in some years, and vitreous, with an intensive red
color. Sadovo 552 is a hard wheat cultivar. The grain has excellent
technological properties and according to its quality parameters,
belongs to the group of strong wheats that improve the quality
of flour. A great advantage of this cultivar is its very good
resistance to Fusarium culmorum. Superior to all other
Bulgarian cultivars, Sadovo 552 can be compared only with the
few well-known sources of resistance to Fusarium in the world.
Sadovo 552 also has a good resistance to bacteriosis. Another
advantage of this new cultivar is tolerance to aluminum, which
makes it suitable for acidic soils.
AGRICULTURE AND AGRI-FOOD CANADA
Cereal Research Centre, 195 Dafoe Road, Winnipeg, Manitoba R3T
2M9, Canada.
Statistics of Canada's November estimate of 1995 wheat production on the prairies:
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Hectares seeded Metric tons
produced
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Manitoba - spring 1,562,000 3,265,900
- durum 60,700 130,600
- winter 4,000 8,200
Saskatchewan - spring 4,775,200 9,125,500
- durum 1,821,100 3,755,700
- winter 30,400 65,300
Alberta - spring 2,387,600 6,412,000
- durum 303,500 843,700
- winter 30,400 81,600
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Identification of extra-strong dough-mixing properties by electrophoretic analysis.
O.M. Lukow and T.F. Townley-Smith.
To study the segregation of specific wheat endosperm
proteins controlling dough strength, a cross was made between
the semidwarf Glenlea and AC Domain. Doubled haploid lines from
the cross produced by the maize pollen technique were used to
elucidate the genetic basis of dough strength. Lines were evaluated
electrophoretically on SDS-PAGE for HMW- and LMW-glutenin composition,
for gluten strength by the SDS-sedimentation test, and by a 10
g mixograph analysis. The extra-strong mixing characteristics
of semidwarf `Glenlea' wheat were found to be the
result of the partially additive effects of the presence of HMW-glutenin
subunits 7+8, including the overproduction of subunit 7, and the
presence of LMW-glutenin subunits 50, 8, and 10. In particular,
the LMW-glutenin subunits appeared to exert a complementary
effect on the mixogram parameters. A total profile of extra-strong
dough properties was evident only in the presence of all Glenlea-type
HMW- and LMW-glutenin protein subunits.
N.K. Howes, T. Aung, R.I.H. McKenzie, D. Brown, and T.F. Townley-Smith.
Rapid progress has been made in applying wheat double
haploids (DHs; using the `wheat X maize' system) to
carry out genetic studies and to identify molecular markers for
disease resistance (BYDV, WSMV, Fusarium head blight, rusts and
smuts, and wheat midge); quality (polyphenol oxidase, gluten strength,
loaf volume, milling yield, test weight, and color retention);
preharvest dormancy (sprouting resistance); and high protein yield.
Twenty-five populations (50-200 lines per cross) were produced
specifically to study the genetics of these characteristics.
In addition, DHs have been applied to the wheat breeding
program, usually in combination with marker-assisted selection
(MAS) of F2 plants or BC1F1 plants to be used as parents for DH
production. In all, over 5,000 wheat DH lines were produced in
last 12 months. Productivity has now increased to 1,000 haploids
per month, but facilities for plant grow-out following chromosome
doubling will limit DH production to about 10,000 lines per year.
Most efforts are now concentrating upon MAS of parents and haploids
or upon other tests that can be applied prior to field evaluations
(especially seed-based tests).
A. Hussain and O.M. Lukow.
We investigated 10 cultivars of Canada Western Extra-Strong Spring (CWES) wheat possessing identical HMW-glutenin compositions. Experimental results confirmed that gluten recovery was influenced by the flour protein content, whereas the strength (quality) of gluten was cultivar dependent. All glutens improved the mixing properties of the base flour (Alpha). However, the magnitude of variation in curve properties relied on the type of supplemental gluten. Gluten prepared from `Glenlea' produced mixograms with the highest mixing development time (MDT), band width energy (BWE), and energy to peak (ETP). The stronger gluten of Glenlea (freshly prepared) showed the most stability to continuous mixing compared to `Alpha' or `Norseman' glutens, which represented the other extreme. Glenlea gluten was tough and required more energy to break during an extensograph stretch, whereas Norseman gluten was more elastic and needed the least amount of force to break. Stronger-type glutens produced more froth during glutomatic washing and were less soluble in 50 % propanol. All of these tests, i.e., amount of
froth, mixing stability, and propanol solubility,
can provide an accurate assessment of gluten quality. Glenlea
gluten showed exceptionally superior characteristics.
T. Aung, A. Hussain and O.M. Lukow.
Crosses involving tetraploid durum wheat (AABB, 2n
= 28) and synthetic hexaploid (AABBDD, 2n = 42) wheats produced
pentaploid seeds (AABBD, 2n = 35) that exhibited differences in
seed morphology and endosperm proteins when pistillate and pollen
parents were crossed reciprocally. Although the embryos of pentaploid
seeds generated by reciprocal crosses had the same chromosome
complement, they differed chromosomally in their seed coat (outer
layers) and endosperm tissue. Seeds from the hexaploid pistillate
parent and tetraploid pollen parent had 42 chromosomes in the
seed coat, 56 in the endosperm, and 35 in the embryo. These seeds
were small, red, and smooth. In contrast, the seeds produced involving
the tetraploid pistillate parent and hexaploid pollen parent had
28 chromosomes in the seed coat, 49 in the endosperm, and 35 in
the embryo. The seeds produced from this cross were large, amber,
shrivelled, and severely deformed. Extracts of endosperm proteins
(SDS/Tris-Hcl, pH 6.8) of these seeds from reciprocal crosses
showed significant differences in their electrophoretic band patterns.
The pentaploids with a single dose of D genome in the endosperm
showed more bands in the slow-mobility region. Insufficient dosage
of D-genome chromosomes could be one of the factors affecting
post-translational expression of endosperm proteins.
Stable D-chromosome disomic addition lines and specific molecular markers.
T. Aung, X. Sun, and J.D. Procunier.
Single D-chromosome addition lines in a tetraploid
wheat (AABB) genetic background are being established. The tetraploid
`Stewart' line (AABB, 2n = 28) was crossed to Ae.
squarossa (DD, 2n = 14), and F1 chromosome doubling produced
the synthetic hexaploid AABBDD (2n = 42). This hexaploid, when
crossed to the Stewart line, produced an F1 progeny with a single
copy of the D genome (AABBD, 2n = 35). Genetically and cytologically
stable single D-chromosome lines were produced by selfing
35-chromosome lines and selecting 29-chromosome monosomic and
30-chromosome disomic addition lines from the selfed progeny.
A RAPD assay is a useful method for detecting molecular
markers. Using these genotypes for identifying RAPD markers specific
for a particular chromosome has distinct advantages: (1) the presence
of a unique band with a particular D chromosome; (2)no confusion
of chromosome RAPD markers with varietal markers as seen in disomic
substitution lines (Wang et al. 1995, Crop Science 35:886);
(3) the genetic stability of the single chromosome addition lines;
and (4) verification of the unique RAPD band can be accomplished
by testing its presence in the AABBD genotype. The RAPD markers
can be converted readily to SCAR (sequenced characterized amplified
region) markers. The use of longer and specific SCAR primers allows
a more robust PCR reaction and the elimination of the multiple-banding
pattern of RAPD primers.
We tested 116 primers for the presence of a unique
band on both the AABBDD and AABBD genotypes and its absence on
the AABB genotype. Of the total number of bands, 4 % were derived
from the D genome, giving a total of 10 D-genome-specific markers.
The assignment of these markers to a specific D-genome chromosome
is currently underway using the single D-chromosome addition lines.
These D chromosome-specific markers/primers are useful for the confirmation of specific microdissected wheat chromosomes or PRINS (primed in situ labelling) detection of individual chromosomes.