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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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 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...
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...
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...
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,...
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....
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 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...
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,...
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...
Crossover frequencies for seven selected regions on five
chromosomes of maize were measured to ascertain the effect of
chelating agents on recombination. Ethylenediamine tetraacetic acid,
EDTA, and dimethyl sulfoxide, DMSO, were used in three concentrations
singly, and in all combinations. Plants heterozygous for
for linked genes governing seed and seedling...
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...
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...
The focus of this study was to determine if S₁ family recurrent
selection might be successfully used for barley improvement.
Objectives were: 1) to identify suitable methods of evaluating grain
yield in small plots, 2) to study the effects of intermating on mean
values and variances of selected agronomic characters,...
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 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...
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...
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....
Despite many investigations genotype by environment interaction remains
one of the least understood factors in plant improvement. Understanding genotypic
differences responsible for such interactions could assist in making more informed
breeding decisions. The components of yield being less complex than grain yield
per se may be useful for selection to...
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...
This study was undertaken to see if a method of handling
segregating populations could be employed which combined the positive
attributes of the traditional pedigree and-bulk methods. Derived F₅
lines from the pedigree, bulk, and what is identified as a modified
bulk method, were obtained from three winter wheat crosses....
A set of genes which show developmental and tissue
specificity are expressed late in embryo maturation during
grain formation in wheat (Triticum aestivum). Two members
of this maturation gene set (MGS) are Em and triticin, a 7S
globulin. Results presented here show that during
embryogenesis, the expression of Em mRNA...
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...
A major factor limiting the efficiency of plant improvement programs is the lack of knowledge as to which parental combinations to make when working with quantitatively inherited traits. The primary objective of this study was to provide information regarding the use of combining ability analysis to predict which cross combinations...