This investigation was motivated by the apparent increase in genetic
variability resulting from the systematic combining of gene pools
represented by winter and spring types of wheats.
It was the objective of this study to provide information regarding
the nature of this genetic variability for nine agronomic characters
in populations...
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...
Concern regarding the lack of genetic variability and the apparent yield plateau reached in wheat breeding have prompted this investigation. The systematic crossing of spring and winter wheat types which have evolved to form somewhat different gene pools, may provide a source of additional usable genetic variability for future yield...
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...
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...
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....
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...
The Asian noodle market is responsible for the increased volume of wheat
imported to that region in recent years. Soft white wheat produced in the Pacific
Northwest is mainly used for baked products, whereas an Australian wheat,
Australian Standard White, is preferred for noodles. To enter this market soft
white-wheat...
Grain yield and grain protein are often negatively associated in
wheat. When yield increases and grain protein decreases, there can be
an adverse effect on the milling and baking quality if the desired end
product is bread flour. It has been suggested that this inverse
association is the result of...
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...
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...
Five winter wheat cultivars and their diallel crosses were evaluated for plant height, harvest index, deading-maturity duration, the components of yield, (spikes per plant, spikelets per spike, kernel weight and kernels per spikelet)and total plant yield. Two diverse locations, Moro, a dryland site (250 mm annually) located in central Oregon...
Barley Yellow Dwarf Virus (BYDV) is a major disease of wheat. Unfortunately, unlike barley where the Yd2 gene provides adequate levels of resistance, the situation in wheat is more complex. This study was designed to provide information regarding: 1) evaluation of methods of measuring resistance among selected cultivars; 2) identification...
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...
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...
Five genetically and morphologically different winter wheat
cultivars, Hyslop (H), Yamhill (Y), Paha (P), Luke (L), and Sprague
(5) were blended in all possible combinations. These composites
plus the five pure stands were planted in the fall of 1973 at three
environmentally diverse locations in Oregon: Hyslop Agronomy Farm,
Corvallis;...
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...
Immature embryo explants taken eight days after anthesis were used
to establish callus cultures of spring barley. Two types of calli
were observed. A soft watery callus which produced a limited number
of shoots and a harder yellowish callus that gave rise to numerous
green primordia and shoots. Gamborg's B5...
The seeds of Douglas fir, a representative of the gymnosperm
flora, were studied at six stages of germination to discern the structures
of food reserves and to study ultrastructural changes occurring
during germination in the embryo and resulting seedlings.
The materials were fixed in three fixatives, dehydrated with
ethanol series,...
Concerns regarding maintaining wheat yield per hectare and extending
the commercial life expectancy of cultivars grown in the Yaqui
Valley of Mexico prompted this investigation. Four genetically diverse
spring wheat cultivars were grown in pure stands and in all possible
combinations at the Northwest Agricultural Research Center at Ciudad
Obregon...
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...
Pre-harvest sprouting in wheat costs farmers millions of dollars every year. Pre-harvest sprouting tolerance (PST) has minimized this problem, but improvement of PST is still necessary. Synthetic hexaploid wheats (synthetics) have been used as sources of
genes coding for many useful traits. Two studies evaluated the PST of a synthetic...
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...
Differential grain yield response of two winter wheat cultivars
('Yamhill' and'McDermid) when grown on acid soils prompted this investigation.
Root samples were taken at two soil depths at late
tillering and anthesis from plots established on an acid nonpareil
soil in Douglas County, Oregon. The soil pH was 5.2-5.3 and...
Four agronomically and genetically diverse winter wheat parents
were utilized as the experimental organisms. Atlas 66 and NB 68513
were selected as cultivars with a high and stable protein content when
grown under different environmental condidtions. They are intermediate
for grain yield when grown in the Pacific Northwest. Yamhill
and...
Factors which influence the effectiveness of making early generation
selections within bulk populations were investigated. Material
utilized included the parents, F₁, and F₂ through F₅ bulk populations
resulting from a diallel cross. Information concerning the response
of two traits, plant height and grain yield, was obtained for these populations
at...
The purpose of this study was to determine the nature and amountof genetic variation and possible associations between winterhardinessand earliness in winter x spring wheat crosses.Four winter wheat cultivars selected for differences in earlinessand winterhardiness were crossed with a nonhardy, day length insensitivespring wheat cultivar. The following year, experiments containing...
Wheat (Triticum aestivum) is the major food crop produced
on the Anatolian Plateau of Turkey where due to limited
rainfall the farmers follow the traditional system of fallow
farming. They are presently producing an average of 1.15
tons of grain per hectare during the crop year. This rate
of production...
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,...
Responses to two cycles of mass selection for heading date,
followed by selfing or intermating, were studied in two diverse
winter wheat (Triticum aestivum L. em. Thell) crosses. Selection
was bidirectional, resulting in early and late populations for
each mating system, cycle, and cross. The influence of mass
selection for...
Until recently, the viscoamylograph had been the primary method for
measuring starch as it relates to noodle quality in wheat. This method
requires a large sample of flour and is time consuming. With the introduction
of the rapid visco-analyser (RVA) in 1986 and the more recent flour swelling
volume procedure,...
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...
Physical properties of gluten and pigment content are of primary importance in determining quality in durum wheat (Triticum turqidum L. var. durum). The objective of this investigation was to evaluate the contribution of different -y-gliadin protein subunits in durum wheat pasta quality as measured by the sodium dodecyl sulphate microsedimentation...
Six wheat hybrids from two sets of parents and their respective
parents were grown at Hyslop Agronomy Farm near Corvallis, Oregon
in the year 1965-66. The object of the experiment was to evaluate the
influence of population densities and different planting patterns on
grain yield and factors which determine grain...
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...
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...
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...
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...
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....
The effectiveness of early generation selection for yield and
yield stability and the possible identification of superior parental
combinations were studied in winter wheat populations representing
different levels of genetic diversity. Experimental material for
evaluating yield stability consisted of nine bulk and seven modified
bulk populations derived from nine parental...