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...
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...
A diallel cross consisting of ten parents was grown on the
Hyslop Agronomy Farm near Corvallis, Oregon, in order to obtain
estimates of the gene action contributing to yield and its components
in wheat. Gene action estimates were obtained by two methods of
diallel analysis and from narrow sense heritability...
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...
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...
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...
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...
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 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...
Studies were conducted to verify the existence of IAA in wheat
seedlings and to determine the effect of (2-chloroethyl)-trimethyl-ammonium
chloride (CCC) on the IAA content of club wheat,
Triticum aestivum compactum, variety Omar. The shoots of CCC-treated
and untreated wheat plants were extracted with ethanol, the
plant extract purified, separated...
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...
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...
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...
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 volatile flavor fraction of lightly milled wheat grown in
eastern Oregon was isolated for study by two methods: steam distillation
under vacuum and steam distillation at atmospheric pressure.
The sample obtained under vacuum was extracted with ether
which was then evaporated to yield the desired wheat essence.
Steam distillation...
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...
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...
A study was made on the effect of CCC (2-chloroethyl)-trimethyl-ammonium
chloride), a plant growth retardant, on the RNA (ribonucleic
acid) content of wheat plants, It was found that the RNA content of
wheat leaves generally decreased with increasing levels of CCC up to
1x10⁻⁵M. Thereafter, the RNA content again increased...
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...
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...