Both red (Trifolium pratense L.) and white (Trifolium repens L.) clover
seed yields can be highly variable and low in western Oregon. The objectives of
this study were to: i) determine crop water requirements and supplemental
irrigation timing, and ii) quantify the effects of soil and water status on
inflorescence...
The production of barley (Hordeum vulgare L.) haploids by crossing with
H. bulbosum is a widely used tool in breeding and genetics. Certain barley
genotypes have low seed set in this interspecific cross, a phenomenon known
as partial incompatibility. Haploid production efficiency and gamete sampling
are important issues with the...
Geostatistical methods were used to find efficient and accurate means for
salinity assessment using regionalized random variables and limited sampling. The
random variables selected, sodium absorption ratio (SAR), electrical conductivity
(EC), and clay content were measured on samples taken over an area of fifteen
square miles. Ordinary kriging and co-kriging...
The CERES-Wheat Crop Growth and Development model treats temperature,
nitrogen and water stresses as limiting factors. For each day the model calculates a
stress index for temperature, N and water, compares the magnitude of the indices,
and then adjusts the calculated daily potential growth using the index of the most...
Sandy soils are among the least productive soils because of their inability to
store adequate water for plant growth. Their high percolation rate not only allows
water to move quickly beyond the root zone, but also washes nutrients below the reach
of plant roots. High evaporation occurs from the soil...
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 usefulness of preplant nitrogen (N) in establishing
alfalfa in colder production areas has not been
well characterized. This study was conducted to determine
the effect of preplant N and soil temperature on
yield, percent N derived from biological nitrogen fixation
(PBNF), and shoot N concentration in alfalfa (Medicago
sativa...
Italian ryegrass growth and production from
positionally selective applications and sublethal rates of a
nonselective herbicide were compared to growth and
production when treated with diuron applied preemergence as
a broadcast treatment and safened by activated carbon
applied over the crop row. In the positionally selective
treatments, herbicide spray was...
No-tillage winter wheat (Triticum aestivum L.) grown in a
wheat-fallow cropping system has consistently produced lower grain
yields than conventionally tilled soils in the semiarid Pacific
Northwest. A 2-year study was conducted in a long-term tillage trial
at Moro, OR to determine factors responsible for differences in wheat
growth and...
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...
Potato leafroll virus (PLRV) causes yield and quality losses in
potato. PLRV is identified by plant symptoms and serological tests
such as an enzyme-linked immunosorbent assay (ELISA). A similar
serological test, direct tissue blotting assay (DTBA), was used to
detect and monitor PLRV movement in field-inoculated Russet Burbank
plants and...
Calls for increased farmer involvement in research and extension programs
have been numerous and well supported. One approach to integrate the collective
knowledge and experience of agricultural scientists and farmers is through whole
farm case studies (WFCS). An interdisciplinary team of 34 research and extension
personnel at Oregon and Washington...
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....
Concerns have been expressed that wheat (Triticum aestivum L.) cultivars selected under optimum conditions may lack adequate adaptation for stress environments. Experimental populations were grown under three environmental conditions 1) optimum, 2) reduced irrigation, and 3) high temperature. Field experiments were conducted at the Center for Northwest Experimental Station (CIANO),...
Legislation to reduce open field burning in grass seed fields within the Willamette valley of western Oregon changed established production practices. In the creeping grasses such as Kentucky bluegrass (Poa pratensis L.) and creeping red fescue (Festuca rubra L.) non-thermal management resulted in reduced yield. Studies were conducted to examine...
The assessment of optimum nitrogen (N) fertilizer need for winter wheat (Triticum
aestivum L.) is important for economic and environmental sustainability. A comprehensive understanding of fertilizer N requirement depends on estimation of the quantity of N needed by the crop versus that supplied by soil.
The objectives of this study...
Birdsfoot trefoil (Lotus corniculatus L.) is a popular perennial, non-bloating forage legume used for pasture, hay and silage throughout the temperate regions of Europe, Asia Minor, North Africa and North and South America. It is regarded as the most morphologically and biochemically variable species in the genus. Research investigating the...
There is no information available on water management of birdsfoot
trefoil grown for seed. Information is also not available describing how to
minimize seed losses due to shattering in order to obtain consistently high
birdsfoot trefoil seed yields. The objectives of this research are to: (i) quantify
crop water use,...
Summer drought is a major factor limiting the regrowth of perennial ryegrass seed crops. This phase of crop development has a strong influence on seed yield because most of the tillers that contribute towards next season's seed crop are produced or regrown during this period. In recent years many seed...
Rotating wheat with other crops is a common practice in the Willamette Valley of
western Oregon. Depending upon previous crop and soil type, current N fertilizer
recommendations for wheat in the Willamette Valley vary widely. Excessive fertilizer
poses environmental risk, whereas lower N inputs than required by the crop represent...
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...