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...
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...
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,...
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 need to develop a shorter life cycle wheat cultivar which
would be more adapted to multiple cropping systems prompted this
study. Thus the following information was obtained.
Greatest variations in developmental patterns were found in the
stem elongation, booting, inflorescence emergence and anthesis for
five winter and five spring...
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...
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 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...
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...
Laboratory studies were conducted under different temperature and moisture regimes to evaluate the effects of temperature and moisture on stand establishment and seedling characteristics associated with stand establishment. Percent stand and days to 25% emergence were used as indexes of stand establishment. Seedling characteristics analyzed were: shoot length, coleoptile length,...
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 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...
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...
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...
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...
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...
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....
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,...
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...
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...
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...
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 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...
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...
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 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 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...
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 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,...
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...
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,...
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...
Four, six-rowed, spring barley cultivars were used as
parental material in this study. The parents were distinctly different
in plant height. Washington-6124-62 is a standard height
selection while Short Wocus and Minn. 66-102 are intermediate.
The fourth parent was a dwarf selection obtained from India. The
two intermediate cultivars and...
Parental and segregating populations derived from four winter x
spring wheat crosses were investigated to obtain information concerning
the inheritance and association of earliness, grain yield and yieldrelated
traits. Feasibility of selecting in early generations for these
characteristics was also evaluated. Four winter wheat cultivars
(Hyslop, Yamhill, Bezostaia 1, and...
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...
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...
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...
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...
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...
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 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...
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...