This study was conducted to investigate the possible contamination
of foreign pollen at different stages of a wheat breeding
program. These included spaced planted F₂ segregating populations,
replicated yield trials and seed multiplication. The experimental
wheat materials consisted of four different F₂ populations, four
cultivars and two experimental lines.
Two...
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...
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...
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...
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....
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...
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,...
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...
To remain competitive in the international marketplace,
soft white wheat cultivars grown in the Pacific Northwest
must have consistent and predictable flour properties
including kernel texture. As a consequence, there is a need
to develop wheat cultivars for specific end uses. Wheat
cultivars with very soft kernels are used largely...
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 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...
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...
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...
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...
Crosses between four near isogenic lines for height reducing genes
Rht₁ and Rht₂ and one agronomically superior dwarf line, including
generations through F₃ with reciprocal backcrosses constituted the
experimental materials. Mean, range and standard deviation values for
eleven traits pertaining to the different generations were obtained.
Heterosis and inbreeding depression...
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...
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...
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...
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...
Effective chemical control of pollination would
provide an alternative to the cytoplasmic male-sterile
system in hybrid wheat (Triticum aestivum L.) production.
The objective of this study was to determine
concentration, formulation, growth stage of application
and genotypic effects on levels of induced pollen
suppression and subsequent natural out-crossing from
foliar...
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...
Parents and progeny populations from a cross of 'Stephens'x 'Tibet dwarf' were grown in a spaced-planted experiment to obtain information concerning the nature of inheritance and possible associations between grain yield and the components of yield. Agronomic traits measured on an individual plant basis were: heading date, days to maturity,...
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...
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,...
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 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...
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...
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...
Three stem rust Puccinia graminis graminicola, resistant sources of perennial ryegrass, Lolium perenne, 4A, 48A, and 77A, were crossed in a partial diallel design with one susceptible source, MP-2, resulting in six crosses excluding reciprocals. The F1's and cloned parental populations were inoculated in the field and rated on a...
Four isogenic lines possessing different combinations of height
reducing genes Rht₁ and Rht₂ from 'Norin 10' were crossed to a short
stature, early maturing, septoria susceptible cultivar identified as the
'Tibet Dwarf'. The isogenic lines originated from the backcross
population of 'Itana'/3/'Norin 10'/'Brevor 14'//6*'Itana'. Parents, F₁
and F₂ generations provided...
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...
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...
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...
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 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...
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...
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 regarding the most effective means of evaluating
segregating generations of spring barley prompted this investigation. Three methods of selection were considered: bulk, pedigree, and single seed descent. F₆ lines derived by each method
were grown in a replicated yield trial. The effectiveness of each
method was measured in terms...
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...