Disease has been implied as an important selective
force acting in plant populations. This study was
conducted to determine the effects of stripe rust (Puccinia
striiformis) on the population dynamics of wheat (Triticum
aestivum) cultivar mixtures.
Five wheat cultivars were grown in pure stands and all
possible mixtures at three...
Kura clover (Trifolium ambiguum M. Bieb.) is slow to establish and
has low seed yields the year after establishment. Intercropping a cereal
grain during clover seed field establishment could provide additional
revenue to seed growers, provided that intercropping did not jeopardize
future clover seed yields. Factorial combinations of spring- and...
Farmers and researchers are aware of spatial variation in
grain yield within farms or fields. Fertilizer management may be
improved if techniques can be developed to identify grain yield
variations in wheat fields. Aerial color infrared (CIR)
photography was used to identify winter wheat (Triticum aestivum
L.) canopy biomass variability...
A series of experiments were conducted from 1983 to 1985 to
determine the effects of dinoseb [2-(1-methylpropyl)-4,6-dinitrophenol]
on winter wheat (Triticum aestivum L. em Thell) yields. Field trials
on dinoseb timing and dinoseb plus supplemental pesticides were
established in an effort to elucidate the possible factors involved in
the yield...
Increases in wheat production due to breeding may be reaching
a plateau. The application of N-fertilizer beyond optimum levels
leads to lodging and to an increase in tiller death. The use of
plant growth regulators (retardants) may be an answer for future
increases in production.
Experiments were conducted in 1983...
Nitrogen deficiency during the winter where winter wheat
(Triticum aestivum L.) follows wheat and large amounts of straw
have been plowed down has been a factor limiting yield in the
Willamette Valley of western Oregon. Field experiments were
established to determine if an application of N on the stubble or...
Germination of immature (Stage III) and mature (Stage V) wheat (Triticum aestivum L. var. Chinese Spring and Yamhill) embryos is prevented by the inclusion of 10⁻⁴ M abscisic acid (ABA) in culture medium. In addition, Stage III embryos develop into mature embryos in culture medium containing ABA. In the absence...
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...
Dryland winter wheat in eastern Oregon is usually subjected to
water stress several times during the growing period. Moreover, the
last three months of growth period depend strongly on the available
soil water. The fertility level, stage of growth, availability of
soil water and climatic conditions all interact to determine...
Volunteer winter wheat (Triticum aestivum 'Daws')
severely suppressed growth of fall-planted alfalfa
(Medicago sativa (L.) 'Vernal') seedlings. Wheat
competition began soon after alfalfa emerged and continued
until the first forage harvest the following May. Alfalfa
yield at the first cutting was reduced by 1% for each day
volunteer wheat was...
Wheat endosperm morphogenesis was studied by light microscopy
during the entire growth period of anthesis to maturity. Four
developmental stages have been described in this thesis: (1) double
fertilization, (2) formation of the lower endosperm cells, (3)
termination of nuclear divisions, and (4) initiation of protein
bodies.
The first manuscript...
Visual selection for grain yield may be a limiting factor in
identifying superior yielding genotypes in a breeding program. This
investigation was conducted (1) to compare the effectiveness of
visual selection for grain yield by three selector groups representing different levels of plant breeding experience, and (2) to
examine the...
Deliberately underirrigating a crop may yield economic
benefits. The optimal use of water by an irrigator
should be achieved under a deficit irrigation regime. It
is important to know how water deficits affect yields and
the interaction of the deficits with the scheduling of
irrigations.
A field experiment was conducted...
Stand establishment plays a significant role in the development
and yield of winter wheat (Triticum aestivum L.). Availability of
soil moisture to the germinating seed is one of the most critical
factors affecting stand establishment. Water injection is a method
of applying supplemental moisture to the soil in direct contact...
Four winter wheat cultivars, Bezostaya, Maris-Hobbit, Roussalka
and Stephens, selected on the basis of the diversity of their pedigree and phenotype, were planted at Hyslop Experiment Station near
Corvallis in Western Oregon to study their performance at three
different row spacings (10, 16 and 24 cm), three seeding rates
(100,...
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...
The objective of this study was to determine interrelationships among agronomic traits in early and late maturing populations. Two populations were obtained from the crosses, Roussalka/Tesopaco 76 and Yamhill/Aspen. Seeds were space planted with split plot design and nine agronomic traits were observed. In comparative studies between early and late...
Three chemicals SD 55446, SD 55447 and WL 84245 were found to
induce male sterility in cultivars of wheat or triticale. Both SD 55446
and SD 55447 when applied at a concentration of 0.896 kg/ha resulted
in 90% male sterility. However, SD 55447 caused female sterility at
the same concentration...
With the development of new selective herbicides and the frequent
change in commercial wheat cultivars, information is needed as to the
possible interaction between cultivars and herbicides. The responses
of five genotypically diverse wheat cultivars (Bezostaya, Daws, Maris
Hobbit, Stephens and Yamhill) to diuron [3-(3,4-dichloropheny1)-1,1-
dimethylurea], diclofop methyl 2-[4-(2,4-dichlorophenoxy)phenoxy]
propanoate...
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 major objective of this study was to determine why certain
winter wheat cultivars, when hybridized, will produce a greater proportion
of desirable plants in subsequent, segregating generations.
Three winter wheat parents were chosen as the experimental material,
based on their known performance as parents. Yamhill and
Pullman Selection 101...
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...
The effect of cooked wheat bran on the excretion of
fecal nutrients, fecal weight, and transit time was investigated
in 10 men, aged 20 to 35 years. The study was
divided into three 18-day periods. The subjects were
divided into two groups; one received the basal diet supplemented
with 15...
Two experiments were conducted to determine the effects of
moisture stress on physiological changes that occur during the vegetative
and reproductive stages of the wheat (Triticum aestivum L.)
plant, and to relate these effects to seed yield, quality and performance.
In a field experiment, different levels of moisture stress were...
The objective of this research was to identify the
optimum cultural practices for the production of the highest
quality wheat seed in Oregon. The production methods
included locations, irrigation, N levels and seeding rates.
The seed quality factors studied were seed weight, bushel
weight, protein content and seedling vigor.
Foundation...
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...
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;...
The effects of soil moisture (-2 to -17 bars), temperature (5 to 20°C), bulk density (0.90 to 1.40 gm/cm³) and texture (Bashaw silty clay and Woodburn silt loam) on germination and seedling emergence of three varieties (Yamhill, Bezostaya, Kirac 66) of wheat (Triticum Aestivum, L.) were evaluated under laboratory and...
Five newly released and two Eastern European winter wheat
cultivars were grown under five different seeding rates (80, 160,
240, 320, 400 seeds per m²). Four of these newly released cultivars
were grown at three different locations which have different environmental
conditions. Data were obtained on grain yield, tiller number...
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...
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...
The purpose of this study was to evaluate the effect of seed
protein content on plant growth of barley (Hordeum vulgare L. )
and wheat (Triticum aestivum L. ). The effects of nitrogen application
on chemical and morphological characteristics of the seed
were also studied.
Seeds of 'Casbon' winter barley...
The effect of soil temperature and plant water stress on nitrogen
uptake, growth rate and transpiration rate of wheat (Triticum aestivum
VILL. , Host) seedlings was studied. A special apparatus for the control
of plant water stress and root temperature was used.
Leaf area was measured by the air flow...
The effect of soil temperature and soil water suction on the rate
of phosphorus uptake and growth rate of wheat (Triticum aestivum
VILL. ,
Host) was studied.
Plants were grown in perlite slabs
separated from an osmotic solution by a semi-permeable membrane.
Measurements were made at temperatures of 10.0, 18.3,...
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...
Several studies were conducted to determine the influence of
various environmental factors on the toxicity of 2-tert.butylamino-
4-ethylamino-6-methylthio-s-triazirxe (Igran) to winter wheat.
The effect of temperature on Igran toxicity was studied by
growing wheat plants in pots submerged in water baths to control soil
temperature and in controlled-environment chambers. Igran...
Studies of some components of test weight in Soft White wheat
revealed distinct subclass differences. Wheat kernels of Soft White
more completely occupied a given volume than did kernels of White
Club. The Soft White kernels were larger and had a higher density
than the White Club kernels. Because of...