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...