Concerns about the genetic control and environmental influence
of various stages of development including the grain filling period,
and the relationship between early maturity and grain yield prompted
this study.
The experimental material consisted of two facultative and two
winter wheat cultivars. A dial!el cross, excluding reciprocals, was
also developed...
The nature of inheritance and possible associations for traits
influencing earliness and grain yield were investigated using a four
parent diallel of winter and spring wheat cultivars.
More genetic variability was observed for the traits measured in
segregating populations resulting from crosses between winter and spring
type wheats in contrast...
A great potential for increasing upland rice production exists in
the savanna soils of Colombia. These vast areas are currently
underutilized. However, they have good soil structure, flat
topography, coupled with sufficient and well distributed rainfall,
making savanna soils ideal for upland rice cropping system. The major
constraints to upland...
A nutrient solution technique developed for wheat was used to
determine tolerance of rice cultivars to aluminum (Al) toxicity.
Pre-germinated rice seed was placed on top of a screen and allowed
to grow on the Al-free solution for 72-96 hours or until the primary
root was 2-3 cms long. Seedlings...
A technique previously designed to screen wheat cultivars and
segregating populations for tolerance to Aluminum utilizing nutrient
solutions in growth chambers was found to be efficient in differentiating
among cultivars of wheat, rye, and triticale for tolerance to Al
under greenhouse conditions. A 5°C increase in temperature, from
25°C to...
The genetic variability in and association between 14 traits that affect maturity, yield, and chemical properties of its product. The plant characters measured were: vigor, flowering date, harvest date, yield, lateral length, nodes per lateral, cones per lateral, cones per vine, cone weight. Alpha-acid and beta-acid content of the cone,...
The nature of the genetic variation associated with a cross involving winter and spring wheat parents for four quality factors was evaluated. Yamhill, a soft white winter wheat, and Inia 66, a hard red spring wheat, were selected as parents for this study. They represented distinctly different phenotypes for the...
Influence of abiotic and biotic factors were examined in selected
winter wheats previously identified as representing a range of
responses to septoria infection. In the greenhouse two and three
inoculations identified resistance when disease severity was assessed
either for the top four leaves or the flag leaf respectively. Kernel
number...
The lack of information regarding the inheritance of the duration and rate of
grain filling, and the possible relationship between grain fill and grain protein
content in wheat prompted this study.
Early maturing Chinese cultivars, 'AI Feng 2' and 'CB 83-52', and late
maturing cultivars adapted to Oregon, 'Stephens' and...
The F₂ progeny from a diallel cross involving seven winter
wheat parents along with the parents were grown at the Hyslop
Agronomy Farm near Corvallis, Oregon to determine the influence
of three plant densities on gene action estimates for yield and its
primary components. The plant densities were designed to...
Ten wheat crosses (four winter x spring and six winter x winter)
involving F₃ and F₄ generations and their respective winter parents
were used to determine whether the early generation selection would
be effective for kernel hardness and grain protein content. In
1980, twenty individual F₂ plants were selected with...
Concerns about the possible reciprocal differences resulting from
systematic crossings of winter and spring wheat gene pools prompted
this investigation. If traits can be improved by simply reversing the
direction of a cross, then identification of the best female parent in
a cross would be helpful for breeding programs.
Two...
Parental lines, Fi's and segregating populations (F₂, F₃ and BC's) including reciprocals were evaluated under field conditions to determine if genetic resistance per se exists for Septoria Leaf Blotch in a selected winter wheat cross. The experiment was conducted over a three year period with both natural infection and artificial...
Six winter wheat cultivars were evaluated for their breeding
value in transmitting superior genetic factors for grain yield to subsequent
progeny. The cultivars were selected on the basis of their
potential grain yield and divided into two populations. Population I
was comprised of three cultivars which have been in commercial...
The response of two newly released cultivars of winter wheat
when grown under different row spacings, seeding rates and nitrogen
levels were investigated. Measurements made included grain yield,
tiller number per unit area, plant height, 300 kernel weight, bushel
weight and protein content of the grain. Hyslop and Yamhill cultivars...
Durum wheat cultivars for North-Eastern Oregon have to be competitive
in terms of their yield potential with soft white winter wheat cultivars and meet
strict quality requirements of the milling industry. Combining the high yield
potential of fall planted durum wheat cultivars which have an acceptable level of
winter hardiness...
Three genetically different dwarf cultivars of spring wheat were
evaluated as potential sources of short stature to use in a wheat improvement
program. The study involved a five parent diallel cross
which included a semidwarf, a standard height and three dwarf cultivars.
The genetic sources of dwarfism included a Norma...
The objective of this study was to compare three genetically
different groups of winter wheat for their grain yield. Experimental
material consisted of parental lines grown in pure stands, hybrids, and
1:1 mixtures of the parental combinations. Three sites were employed to
evaluate possible interactions between the different groups across...
The success of a plant breeding program depends upon the availability of
useable genetic diversity. Such diversity may be enhanced depending on the type of
hybridization strategy employed. Segregating progenies resulting from F2
populations, a double cross, and a top cross were compared for the amount of
useable genetic diversity...
To study the grain filling traits in wheat, two winter cultivars
and four spring cultivars were selected. The resulting Fl, F2, F3 and
backcrosses were tested. The following measurements were made:
a) Visual traits for physiological maturity (PM),
b) Grain dry weight accumulation,
c) Regression models for grain filling period,...
Attempts to develop dual-purpose durum wheat cultivars for both pasta and bread-making
have been unsuccessful. To better understand this limitation, thirty durum
genotypes, selected based on their diverse geographical origin, and five bread wheat
cultivars were compared as to their flour mixing properties, dough physical characteristics
and baking performance. The...
A negative relation between grain protein content and
grain yield is frequently observed in wheat (Triticum
aestivum L. em Thell) i.e. as grain yield increases, grain
protein decreases. It has been suggested that the inverse
relation between grain yield and protein is in part the
result of developing high yielding...
Extensive research has been devoted to evaluating potential
genotype-environment interactions. However, plant breeders are still in
need of a simple way to describe how genotypes respond to different
locations and years. In an environmentally diverse state like Oregon,
significant genotype-environment interactions do occur The resulting lack
of association between actual...
This investigation was conducted to provide information regarding
1) the relationship between the nitrogen percentage in the vegetative
tissue of wheat and barley at various growth stages with grain protein
and 2) to evaluate the possible association between grain yield
and grain protein as influenced by different cultivars, nitrogen
levels...
Strawbreaker foot-rot is a major limiting factor to cost efficient winter wheat
production in the Pacific Northwest. Development of resistant cultivars has been
hindered by the lack of adequate levels of genetic resistance and screening techniques
which can consistently detect desired genotypes.
Studies were conducted to determine if the reported...
Four agronomically and genetically diverse spring
barleys were used in a crossing program to study the
inheritance of lysine in barley and to determine its
possible association with certain agronomic and morphological
characters. The cultivar Hiproly was used as the
source of high protein and lysine. Characters measured
included plant...
The effects of some soil- and foliar-borne biotic factors on
grain yield and the components of yield were evaluated using five
winter wheat varieties sown at two dates. Within each planting date,
varieties were grown under four different combinations of two soil
treatments (fumigation and nonfumigation) and two foliar treatments...
Six genetically diverse dwarfing sources of winter wheat were compared to four isogenic lines for the height reducing genes Rht₁ and Rht₂. Parents and generations through the F₃ including backcrosses to the respective parents were analyzed. Seedling response to gibberellic acid and tests for allelism for plant height were employed...
This investigation was motivated by the introduction of the new
nearest neighbour analyses which reportedly provided a better control
of soil gradients than conventional experimental methods.
Three nearest neighbour analyses and six other analyses were
compared with the completely randomized design or the randomized
complete block design in reducing the...
Seven winter wheats were evaluated for plant height, the components
of yield and yield in a diallel cross at Pendleton, Oregon and
Lind, Washington. An additional parent was added to the diallel cross
at Pullman, Washington. Two levels of nitrogen and five replications
were utilized at each of the locations....
The need to develop a shorter life cycle wheat cultivar which
would be more adapted to multiple cropping systems prompted this
study. Thus the following information was obtained.
Greatest variations in developmental patterns were found in the
stem elongation, booting, inflorescence emergence and anthesis for
five winter and five spring...
Drought is a major limiting abiotic stress influencing wheat production in
many parts of the world. The erratic nature of water deficits makes breeding
and selection for drought resistance deficient. In environments with late
season drought stress, yield losses are usually associated with kernel abortion
or reduction in kernel growth....
A higher level of efficiency in the production of doubled-haploids must be achieved if
this procedure is to be beneficial in plant improvement. Of equal importance is the
development of protocols, which are not genotypic specific and result in progeny that represent
a random sample of gametes from the parental...
The objective of this investigation was to evaluate the
possibility of developing high yielding wheat cultivars whose flour
would result in acceptable loaf volumes for non-traditional bread
wheat growing areas. Spring wheat germplasm employed included high
protein hexaploid derivatives from Triticum dicoccoides, and
selections from Argentina with good bread milling...
Winter wheat cultivars (Triticum aestivum) were evaluated for
their response to water stress and adaptability to a wide range of
moisture limited environments. Grain yield was analyzed for ten
cultivars at six locations across four years. Regression of the cultivar
mean on the year-location mean was used as a measure...