UNIVERSITY OF SASKATCHEWAN
Department of Crop Science and Plant Ecology and Crop Development
Centre, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada.
Global warming? Maybe, but something is certainly
causing unusual weather. The average temperature for November,
December, and January in Saskatchewan was the coldest ever recorded.
The 1996 crop year started cool and wet and seeding was delayed
until late May and early June in much of Saskatchewan. Warmer
weather during the summer allowed the crop to partially catch
up. Unfortunately, the weather turned cool and wet in September,
delaying ripening and harvesting. An early October snow finally
put an end to harvest. Wheat yielded a record 2.44 T/ha for the
three prairie provinces. However, some of the crop was degraded
by weathering and sprouting, and about 1.0 MT are still in the
field and perhaps will be harvested in the spring.
The genes for stem rust resistance in St. 464 durum wheat.
Recently, I reported the transfer of two genes for
stem rust resistance from St. 464 to bread wheat (Can J Plant
Sci 76:317-319, 1995). The two genes were previously
transferred into Stewart durum to produce the cultivar Stewart
63. One of the genes was identified as Sr7a, but a monosomic
analysis failed to locate the second gene. Dr. R.A. McIntosh
suggested that it could be Sr13 and to recheck chromosome
6A. In checking seed stocks for crosses with monosomic 6A, five
F1 plants did not have any cytology. The five F2
families were grown and tested with stem rust race 15B-1.
Three families were proved to have come from disomic F1
plants and segregated 34 R:13 S. Two families came from monosomic
F1 plants and segregated 36 R:4 S. Thus, the gene
appears to be on chromosome 6A. A cross is being made with a
line carrying Sr13.
Evaluation of spring wheat for resistance to the orange
wheat blossom midge.
P. Hucl, R. Graf1, F.W. Sosulski, and C. Gillott2.
Pool, Agricultural Research and Development; and 2Department
of Biology, University of Saskatchewan.
The orange wheat blossom midge has the potential
to severely reduce the quantity and quality of spring wheat grain.
All Canadian spring wheat cultivars evaluated at the time of
a wheat midge outbreak in 1983-84
were susceptible to the pest. The primary objective of this project
will determine whether spring wheat genotypes can be selected
for resistance to the midge on the basis of phenolic acid content
of the grain. Twenty-six homozygous spring wheat breeding
lines and six cultivars were evaluated at Saskatoon and Watrous,
SK, in 1995. In addition, 77 Plant Introductions were evaluated
for wheat midge infestation. The breeding lines were derived
from crosses between Canadian germplasm and the German cultivar
Arin. Arin is reported to be partially resistant to S. mosellana
(Basedow 1977). Averaged over the two sites, Arin had a floret
infestation level of 7 %. The cultivars Laura, CDC Teal, Katepwa,
and Roblin had levels of 11, 15, 18, and 26 %, respectively.
Thus, there was up to a 3.7-fold difference in infestation
level between Arin and the Canadian cultivars. Arin averaged
1.28 larvae/infested floret compared to 1.48, 1.66, 1.71, and
2.10, for Laura, CDC Teal, Katepwa, and Roblin, respectively.
The experimental lines ranged from 5 to 26 % in floret infestation.
Emergence and flight activity of the insect were detected over
a 5-week period at both test sites. None of the wheat lines appeared
to avoid or escape pest infestation as a result of phenological
differences. Floret infestation and grain damage were highly
correlated (r = 0.91**). The level of insect infestation was
negatively correlated with ferulic acid content of the grain (-0.51**).
(This research is currently being funded through the Canada-Saskatchewan
Green Plan and the WGRF Producer check-off.)
Variation for seed dormancy in tetraploid wheat species.
P. Hucl, D. Huel, D.R. Knott, and R. Tavakkol-Afshari.
The current cultivars of durum wheat grown in western
Canada have low to moderate levels of resistance to preharvest
sprouting. The objective of this research is to identify accessions
of tetraploid wheat with elevated seed dormancy levels that might
be used for cultivar improvement purposes. Over 600 accessions
obtained from the USDA wheat collection were screened for seed
dormancy in 1993. Accessions of seven species were evaluated.
In total, 110 (18.2 %) of the accessions exhibited significantly
(P = 0.05) lower seed germination levels at 28C
than the most dormant durum control cultivars, Kyle and Plenty.
In 1994, 100 accessions representing the least (n = 23) and most
dormant (n = 77) selections were retested. Based on 2 years of
high-temperature germination tests, the 19 most dormant accessions
were germinated at 15C.
Based on that test, the three most dormant tetraploid accessions
were evaluated for length of dormancy period. One accession of
T. polonicum with significantly better dormancy levels
than the durum control cultivars has been identified. The free-threshing
accessions evaluated in 1994 were retested in 1995 as part of
a Ph.D. project initiated by R. Tavakkol-Afshari.
Variation for starch content and quality in Canadian spring
P. Hucl, R. Chibbar1, T. Demeke1, and T. Nakamura.
1Plant Biotechnology Institute.
The development of spring wheat cultivars with increased
levels of endosperm starch will become a breeding objective as
modified starch mutants are identified and characterized. Our
initial study determined the repeatability of starch content in
two sets of spring wheat cultivars grown at Saskatoon over a 4-year
period. The repeatability of starch content was compared to that
of grain protein content. Starch content of the cultivars ranged
from 64.6 to 71.6 % in the first experiment, and from 66.6 to
74.2 % in the second experiment. Canada prairie spring wheat
cultivars had the highest starch content. In the first experiment,
repeatability of starch determinations increased from 0.52 (single
to 0.87 (4 years-2
replications per year). Grain protein content values of 0.67
to 0.90 were obtained at the same levels of replication. Similar
results were obtained for the second experiment. Starch and protein
content were negatively correlated.
The starch quality aspect of this project has focused
on the identification of germplasm with reduced amylose content
in order to develop partially and fully waxy starch cultivars.
To date, we have succeeded in identifying a number of Australian
and Japanese wheat accessions that are being used as donors of
waxy genes for backcrossing to a number of Canadian cultivars.
Variation for starch quality in the current Canadian spring wheat
cultivars appears to be very limited, thus we need to incorporate
germplasm from elsewhere. (This project is funded by the Saskatchewan
Agriculture Development Fund.)
Genetic control of bunt resistance in wheat.
C. He and G.R. Hughes.
The genetic control of resistance in two spelt wheats
(RL5407 and SK0263) and two spring wheats (Kite and Triple Dirk)
is being studied as part of a program to identify different sources
of resistance to common bunt in wheat. Preliminary data indicates
that one major gene controls resistance to race T1 (T. caries)
in RL5407 and Triple Dirk, one or two major genes in SK0263, and
at least two genes in Kite. Selection for resistance based on
these genes should be very effective, because the heritability
of resistance ranged from moderate to high and the major type
of gene action was additive. These genes are being transferred
into suitable CWRS genotypes, and their relationship to other
known bunt resistance genes is being determined. (This project
forms part of Mr. He's Ph.D. research and is funded by the Saskatchewan
Agriculture Development Fund.)
Molecular markers for genes for resistance to Septoria nodorum
H. Ma and G.R. Hughes.
Research is in progress to find molecular markers
useful for identifying major genes for resistance to S. nodorum
blotch in durum and bread wheat. Mapping populations, based on
F5 or F6 lines, have been produced for durum
wheat crosses of Sceptre (susceptible cultivar) with resistant
lines S12-1, S9-10, and S3-6; and being produced
for common wheat crosses `861WMN2137
(resistant) / Kenyon (susceptible)',
/ Glenlea (susceptible)',
(resistant) / Kenyon'.
Genetic studies suggest that resistance in S12-1, S9-10,
and S3-6 is controlled by a single gene, in EE8 by two genes,
and in 861WMN2137 by three genes. Using PCR, a number of RAPD
primers have been tested, for ability to produce polymorphisms
among the parental lines and three resistant and three susceptible
families of the `S12-1
cross. One primer, OPB-4, generated a band that is present
in the susceptible parent Sceptre and the susceptible families,
but absent in the resistant parent S12-1 and the resistant
families. A repeat test with seven resistant and six susceptible
families showed that this band is a reproducible, major band and
was present in all six susceptible families. This primer represents
a potential molecular marker for the resistance gene in S12-1.
(This research is funded by the Saskatchewan Agriculture Development
Expression of the cold-induced wheat gene Wcs120, and its homologs in related species and interspecific combinations.
A. Limin, M. Houde1, L.P. Chauvin1, Brian Fowler, and Fathey Sarhan1.
des Sciences Biologiques, University du Quebec
There are species in the Triticeae group that are
crossable with wheat and possess superior cold tolerance, making
them potential gene donors for the improvement of cold tolerance
in wheat. The production of fertile amphiploids from interspecific
crosses of hexaploid or tetraploid wheat with rye or one of the
wheatgrasses holds the possibility of combining the cold tolerance
of these related species with the desirable characteristics of
wheat. Although there have been reports of wheat-rye
amphiploid triticales, or wheat-Agropyron
'perennial wheat' with superior cold tolerance, a large cold hardiness
advantage was not observed for interspecific crosses made in our
Low-temperature response was studied at the
whole-plant and molecular level in wheat-rye
amphiploids and in other interspecific combinations. The cold
tolerance of interspecifics whose parents diverged widely in hardiness
levels resembled the less hardy, higher ploidy level wheat parent.
Expression of the low-temperature induced Wcs120
gene of wheat, which has been associated with freezing tolerance,
was used to study mRNA and protein accumulation during cold acclimation
of the interspecific and parental lines. Northern and Western
analyses showed that homologous mRNAs and proteins were present
in all the related species used in the experiments. Cold-tolerant
rye produced a strong mRNA signal that was sustained throughout
the entire 49-day cold-acclimation period evaluated.
The wheats produced a mRNA signal that had diminished after 49
days of low-temperature exposure. The wheat-rye
triticales did not exhibit the independent accumulation kinetics
of the cold-tolerant rye parent, but rather more closely
resembled the wheat parent in that the mRNA signal was greatly
diminished after 49 days of low-temperature exposure. Protein
accumulations in the wheat-crested
wheatgrass interspecific hybrids also resembled that of the wheat
parent. Consequently, although all parental mRNAs were expressed
in the interspecifics, levels of mRNA and protein accumulation
suggest that the genes of the parental species in these interspecific
hybrids were mainly under wheat regulatory control. (This was
a cooperative project between the Crop Development Centre, University
of Saskatchewan and the Universite
The research was supported by NSERC grants.)
Expression of low-temperature tolerance shown to be
regulated by vernalization genes in cereals.
B. Fowler, L.P. Chauvin1, A. Limin, and F. Sarhan1.
des Sciences Biologiques, Universite
Low temperature is one of the primary stresses limiting
the growth and productivity of winter cereals in western Canada.
Winter cereals acclimate to low-temperature when exposed
to temperatures colder than 10C.
However, they gradually lose their ability to tolerate subfreezing
temperatures when they are maintained for long periods of time
at temperatures in the optimum range for low-temperature
acclimation. The overwinter decline in low-temperature response
has been attributed to an inability of cereals to maintain low-temperature
tolerance genes in an up-regulated state once vernalization
saturation has been achieved. The low-temperature induced
Wcs120 gene family was used to investigate the relationship
between low-temperature gene expression and vernalization
response at the molecular level in wheat and rye in the present
study. Level and duration of gene expression determined the degree
of low-temperature tolerance, and the vernalization genes
were identified as the key factor responsible for the duration
of expression of low-temperature-induced genes. Spring-habit
cultivars that did not have a vernalization response were unable
to maintain low-temperature-induced genes in an up-regulated
condition when exposed to 4C.
Consequently, they were unable to achieve the same levels of
low-temperature tolerance as winter habit cultivars. A close
association between the point of vernalization saturation and
the start of a decline in Wcs120 gene family mRNA level
and protein accumulation in plants maintained at 4C
indicated that vernalization genes have a regulatory influence
over low-temperature gene expression in winter cereals.
(This was a cooperative project between the Crop Development Centre,
University of Saskatchewan and the Universite
The research was supported by NSERC grants.)
ITEMS FROM THE PEOPLES REPUBLIC OF CHINA
HENAN ACADEMY OF AGRICULTURAL SCIENCES
Wheat Institute, Zhengzhou, Henan 450002, Peoples Republic of
Zuoji Lin, Shenghui Jie, and Sicheng Zhang.
A dry winter and early spring caused less tillering. However, abundant, late-spring rainfall increased the number of kernels per spike and kernel weight. Harvest in the rainfed-region increased significantly, although lodging occurred in some high-yielding areas. The total yield of the entire province was the highest ever, greater than 20 million tons.
Mutation of several wheat characters under aerospace conditions.
The mutagenic effects of conditions in aerospace
on some characteristics of the wheat variety Yu-Mai 13 were examined
by means of satellite and high-space balloon. The performance
of 14 lines of an SP3 generation showed that plant
height, kernel weight, florets per main head, length and width
of leaf, heads per plant, and weight per plant all were significantly
different. However, the coefficients of variation for each of
the characters in each line were similar to the control. Two
lines superior to the control were selected. Space-flight conditions
could induce the number of available mutations in a crop and could
be a new way of mutation breeding.
NANJING AGRICULTURAL UNIVERSITY
Wheat Breeding Institute, Nanjing 210095, Peoples Republic of China.
Guo-Liang Jiang, Shi-Rong Yu, Xi-Zhong Wei, You-Jia Shen, Yong Xu, Zhao-Xia Chen, and Shi-Jia Liu.
Inheritance study on sprouting resistance in white wheat.
Thirteen white- and one red-grained cultivars
or strains were selected as sprouting-resistant parents and crossed
with susceptible genotypes in Nanjing during 1993-96,
to determine the inheritance of preharvest sprouting tolerance
in white wheat germplasm. There were significant differences
in the percentage of sprouting in F1s between 28 reciprocal
crosses. The average percent of sprouting in the ear for the
F1, F2, and the parents of 9 `resistant
x susceptible' and 12 `susceptible
x resistant' combinations showed that maternal effects existed
in both F1s and F2s. Sprouting tolerance
was dominantly inherited as a quantitative trait in most cases,
although there were major gene effects and inheritance was partially
recessive. The average broad-sense heritability was 63.07 % for
all combinations. The sprouting percent of hybrid progenies was
reduced by backcrossing with the resistant parents. Selections
made in the early to middle progenies and backcrossing would be
effective for developing white wheat cultivars with preharvest
Analysis of combining ability for preharvest sprouting tolerance
in white-grained wheat germplasm resources.
Twenty sprouting-resistant white-seeded
cultivars or advanced lines and one red-seeded strain of bread
wheat, with different genetic backgrounds, were selected as parents
to study preharvest sprouting tolerance in white-grained germplasm.
Two sets of incomplete diallel crosses were made in `4
blocks. The combining ability of the percent of sprouting in
the ear was made on the parents and F1. The variance
of the general combining ability and specific combining ability
were highly significant, and the additive effects of the genes
played a major role in the inheritance of the sprouting tolerance
in white wheat. The resistant parents had a much greater impact
on the performance of an F1 hybrid in sprouting resistance
than did the susceptible parents. The mid-parent heterosis
in the F1 varied with the parent and the combination.
Estimates of the broad-sense and narrow-sense heritability
were 70.27 %-93.34
% and 54.53 %-65.12
%, respectively, indicating that selection for the resistance
could be made in early to middle progenies of the hybrids. WXBMZ,
SNTTM, WY/120/E6, and Fengchan 3 had a better general combining
ability and should be used as the white-seeded resistant
parents in wheat breeding for preharvest sprouting tolerance.
Comprehensive population improvement for scab resistance
and agronomic traits in wheat.
Two wheat populations, GPI and GPII, were established
based on multiple-parent crossing using the Taigu male-sterile
gene Ta1(ms2), followed by discarding undesirable
combinations, selecting superior male-sterile plants, and
then bulking the seed of selected plants. Phenotypic mass-plant
selection was applied to the male-sterile plants within each
population to improve resistance to scab and agronomic traits
simultaneously. Selection cycles 0 and 3 were evaluated for the
resistance to scab and agronomic characters. Inoculations with
the scab fungus was by single-floret inoculation with F.
graminearum. The number of diseased spikelets indicated the
level of scab resistance. Mean resistance of each population
was significantly enhanced by three cycles of selection for an
increased frequency of resistant plants. The selection response
averaged 7.87 % and 3.24 % per cycle for GPI and GPII, respectively.
Most agronomic traits observed were obviously improved in both
of the populations. From generation C0 to C3,
selection gains from 6-49
% were obtained for number of spikes and grains, biomass, grain
yield per plant, harvest index, and grain number and weight per
spike. Kernel weight and biomass per culm increased by about
8 % in GPI and plant height decreased by 5.48 % in GPII. Scab
resistance and agronomic traits in wheat apparently can be simultaneously
improved through recurrent selection.
Combining ability analysis of scab resistance in the F1
and F2 of a `4
x 5' diallel cross of
Nine genotypes with different levels of resistance
and genetic backgrounds were crossed in a `4
incomplete diallel to choose and effectively utilize scab-resistant
parents in a wheat breeding program. A field trial of parents,
F1s and F2s was conducted in a 3-replicate
randomized block design at Nanjing. The number of diseased spikelets
was observed to assess the fungal-spread resistance by single-floret
inoculation with F. graminearum. The average number of
diseased spikelets in the F1 and F2 was
less than the midparent values for most combinations, indicating
dominant effects of the resistance genes. Parental versus F1
effects and the average degree of dominance showed that midparent
heterosis contributed mainly by superdominance. General and specific
combining ability effects were significant in both the F1
and F2. Additive effects of the resistance genes played
a major role in the inheritance of resistance in the F2,
but were less than nonadditive effects in F1. Thus,
parent selection for breeding pure lines should be based mainly
on a combining ability analysis in the F2. Correlation
analysis also showed the complicated inheritance of scab resistance
in wheat. The effects of resistance levels of the parents and
their interaction in the offspring should be considered. The
use of these two new sources of resistance is suggested for use
in breeding programs.
Jiang GL and Wu ZS. 1996. Development of scab-resistant
gene pool and its application to wheat breeding. J Nanjing Agric
Jiang GL, Chen ZX, and Wu ZS. 1995. Screening white
wheat germplasm for pre-harvest sprouting tolerance. In:
Seventh Inter Symp Pre-Harvest Sprouting in Cereals (Noda
K and Mares DJ eds). pp. 213-217.
Jiang GL, Chen ZX, and Wu ZS. 1997. Studies on
the development of scab resistant gene pool in wheat. V. Comparison
of the effect of population improvement of different gene pools.
Acta Agronomica Sinica 23(1):In press.
Jiang GL, Chen ZX, and Wu ZS. 1997. Studies on the development of scab resistant gene pool in wheat VI. Comprehensive analysis and comparison of the scab resistance and agronomic traits of recurrent selection strains and their original parents. Acta Agronomica Sinica 23(2):In press.
Huang DC, Jiang GL, Zhuang ZY, Yang ZL, Zhang SN,
and Zhang LQ. 1996. Progress on breeding for scab resistance
(tolerance) by Taigu dominant male sterile gene. In:
Advances in Wheat Breeding Research in China (Zhuang QS and Du
ZH eds), Chinese Agricultural Press. pp. 402-411.
Shen YJ, Liu SJ, and Wu ZS. 1996. A genetic study
on pre-harvest sprouting in hybrid wheat. J Nanjing Agric
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