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United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
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Full-Text Articles in Life Sciences
Accuracy Of Equations Predicting The Phyllochron Of Wheat, Gregory S. Mcmaster, Wallace Wilhelm
Accuracy Of Equations Predicting The Phyllochron Of Wheat, Gregory S. Mcmaster, Wallace Wilhelm
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Predicting the rate of leaf appearance, or phyllochron, aids in understanding and modeling grass development and growth. Nine equations predicting the phyllochron of wheat (Triticum aestivum L.) were evaluated using field data from a variety of locations, cultivars, and management practices. Each equation is referred to by the last name of the first author; if there is more than one equation by the first author, additional descriptors were included. The BAKER and KIRBY equations predict the phyllochron based on changes in daylength following seedling emergence; CAO-TEMP and CAO-DAY use a curvilinear relationship with temperature and daylength, respectively; CAO-T&D uses the …
Corn-Soybean Rotation Effects On Soil And Plant N Indices, G. E. Varvel, N. L. Klocke, Wallace Wilhelm
Corn-Soybean Rotation Effects On Soil And Plant N Indices, G. E. Varvel, N. L. Klocke, Wallace Wilhelm
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
An irrigated study comparing monoculture corn and corn-soybean systems is being conducted on a uniform site in the Platte Valley of Nebraska. Four corn hybrids differing in yield potential, maturity, and stay-green characteristics are used in both the monoculture and rotation systems with five N-fertilizer rates. Stalk nitrate-nitrogen concentrations determined in mature corn plants at harvest have been used in many areas of the country as an indicator of the amount of N available to those plants. In this study, stalk nitrate-nitrogen concentrations (taken after the 1992 and 1993 growing seasons) reflected differences in N status between and within the …
Yield And N Uptake Of Inbred Corn With Reduced N-Fertilizer Application, Wallace Wilhelm, B. E. Johnson, R. Koopman, W. R. Peterson
Yield And N Uptake Of Inbred Corn With Reduced N-Fertilizer Application, Wallace Wilhelm, B. E. Johnson, R. Koopman, W. R. Peterson
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Most corn planted in the United States is a single-cross hybrid; therefore the seed is produced on inbred lines. Inbreds are known to be less productive than the resultant hybrids; however, growers and seed companies want to maximize seed production. To this end growers attempt to keep mineral nutrition, especially nitrogen, non-limiting. Low production potential and high N fertilization rates can result in the likelihood of groundwater contamination. Key to proper N application is knowledge of the N response of inbred lines. The purpose of this research was to determine the yield and N uptake response of a group of …
Addition Of Cellulolytic Clostridia To The Bovine Rumen And Pig Intestinal Tract, Vincent H. Varel, J.T. Yen, Kelly K. Kreikmeier
Addition Of Cellulolytic Clostridia To The Bovine Rumen And Pig Intestinal Tract, Vincent H. Varel, J.T. Yen, Kelly K. Kreikmeier
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Studies were conducted to determine whether intestinal cellulolytic bacteria could be introduced into the bovine rumen or pig large intestine. In the first study, the ruminal fluid of three cows was evacuated and replaced with 20 liters of buffer and 6 liters of the ruminal or swine cellulolytic organism Clostridium longisporum or Clostridium herbivorans, respectively. The introduced organisms were the predominant cellulolytic bacterium in the fluid (>107 cells ml21) at 0 h. C. longisporum was still the predominant cellulolytic organism after 5 h, at 0.55 3 107 cells ml21; however, after 24 h the count of C. longisporum …
Environmental Modification Of Hard Red Winter Wheat Flour Protein Composition, Robert A. Graybosch, C. J. Peterson, P. Stephen Baenziger, D. R. Shelton
Environmental Modification Of Hard Red Winter Wheat Flour Protein Composition, Robert A. Graybosch, C. J. Peterson, P. Stephen Baenziger, D. R. Shelton
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
The intrinsic processing quality of wheat (Triticum aestivum L.) cultivars is modified significantly by cultural conditions and climate. In an attempt to understand the biochemical basis of such variation, environmental modification of flour protein content and composition was measured. Thirty hard red winter wheat cultivars and experimental lines were grown at 17 Nebraska environments during 1990 and 1991. Environmental conditions, including grain filling duration, temperature and relative humidity during grain filling, were monitored. Grain yield and test weight also were determined as environmental indicators. Significant linear correlations between flour protein content, as measured by near-infrared spectroscopy, were observed only …
Umingmakstrongylus Pallikuukensis Gen. Nov. Et Sp. Nov. (Nematoda: Protostrongylidae) From Muskoxen, Ovibos Moschafus, In The Central Canadian Arctic, With Comments On Biology And Biogeography, Eric P. Hoberg, Lydden Polley, A. Gunn, J. S. Nishi
Umingmakstrongylus Pallikuukensis Gen. Nov. Et Sp. Nov. (Nematoda: Protostrongylidae) From Muskoxen, Ovibos Moschafus, In The Central Canadian Arctic, With Comments On Biology And Biogeography, Eric P. Hoberg, Lydden Polley, A. Gunn, J. S. Nishi
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Umingmakstrongylus pallikuukensis gen. nov. et sp. nov. is established for a protostrongylid nematode in muskoxen, Ovibos moschatus, from the Kitikmeot Region (central Arctic) of the Northwest Territories, Canada. It is distinguished from Cystocaulus and other Muelleriinae by characters that include the following: males: deeply incised, bilobed bursa, independent externodorsal rays, telamon composed of distal transverse plate, absence of falcate crurae, and spicules not distally split; females: absence of provagina; and first-stage larvae: presence of three cuticular folds on the tail. The great length of females (468 mm) and males (171 mm) is exceptional among the Protostrongylidae. Pathognomonic lesions include …
Coordination Of Adsorbed Boron: A Ftir Spectroscopic Study, Chunming Su, Donald L. Suarez
Coordination Of Adsorbed Boron: A Ftir Spectroscopic Study, Chunming Su, Donald L. Suarez
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
We studied B adsorption on amorphous aluminum and iron hydroxides, allophane, and kaolinite as a function of pH and initial B concentration. Boron adsorption lowered the point of zero charge of all four adsorbents, implying specific adsorption (inner-sphere complexation) of B. We provided novel information on the coordination of B adsorbed at mineral-water interfaces by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The ATR-FTIR spectra of interfacial B species were influenced by pH and mineral type. Strong trigonal B and weak tetrahedral B bands of the asymmetric stretching mode were observed on the difference spectra at pH
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Endocrinology Of The Avian Reproductive System, Mary Ann Ottinger, Murray R. Bakst
Endocrinology Of The Avian Reproductive System, Mary Ann Ottinger, Murray R. Bakst
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
The purpose of this review is to provide an overview of the avian reproductive system. Attention is given to the neuroendocrine regulation of hypothalamic and pituitary gland hormones as well as the target tissues regulated by these hormones. Emphasis is placed on the dynamics of the system and the effects of alterations resulting from environmental and other influences on the function of the reproductive system. The ovulatory cycle, oviduct, and shell gland are discussed relative to egg formation and the hormonal regulation of this process. Testicular function and the cellular bases for spermatogenesis and steroid production are also discussed.
Quantitative Mass Production Of Hydrotaea Aenescens (Diptera: Muscidae), Jerome Hogsette, Frank Washington
Quantitative Mass Production Of Hydrotaea Aenescens (Diptera: Muscidae), Jerome Hogsette, Frank Washington
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
A covered oviposition device was developed that allows collection of large numbers of Hydrotaea aenescens (Wiedemann) (formerly Ophyra aenescens) eggs. Eggs can be measured and known numbers added to larval rearing medium so this beneficial fly can be reared quantitatively for the first time. With the use of quantitative rearing techniques and a new diet consisting of 5 parts Gainesville house fly diet and 1 part meat and bone meal, H. aenescens can be mass-reared easily for biological control studies.
Effect Of Semen Storage On The Number Of Spermatozoa In The Perivitelline Layer Of Laid Turkey Eggs, A. M. Donoghue, M. R. Bakst, D. R. Holsberger, D. J. Donoghue
Effect Of Semen Storage On The Number Of Spermatozoa In The Perivitelline Layer Of Laid Turkey Eggs, A. M. Donoghue, M. R. Bakst, D. R. Holsberger, D. J. Donoghue
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
A progressive decline in fertility over the course of egg production may be observed when turkey hens are inseminated weekly with semen stored for 24 h. In vitro storage of spermatozoa before insemination results in lower fertilization, possibly because fewer spermatozoa survive selection and storage in the hen's sperm storage tubules in vivo; alternatively, stored spermatozoa may be as capable of reaching the egg as are fresh spermatozoa, but unable to penetrate and fertilize the egg normally. The objective of this study was to determine whether this decline in fertility is a result of fewer spermatozoa reaching the egg …
Seed Physiology, Production & Technology, Wallace Wilhelm, B.E. Johnson, J. S. Schepers
Seed Physiology, Production & Technology, Wallace Wilhelm, B.E. Johnson, J. S. Schepers
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Detasseling is used in hybrid corn (Zea mays L.) seed production to ensure harvested seeds have the desired genetic complement. Both mechanical and hand detasseling result in loss of some leaf tissue and plant N. The objective of this study was to determine if seed yield and quality and N content of grain and stover were affected by leaf removal during detasseling. The treatments evaluated were removal of tassel only, tassel plus one leaf, tassel plus two leaves, tassel plus three leaves, tassel plus four leaves, and no tissue removed (control). The leaf area index (LAI) declined linearly, about …
Genetic And Phenotypic (Co)Variances For Growth And Carcass Traits Of Purebred And Composite Populations Of Beef Cattle, K. E. Gregory, L. V. Cundiff, R. M. Koch
Genetic And Phenotypic (Co)Variances For Growth And Carcass Traits Of Purebred And Composite Populations Of Beef Cattle, K. E. Gregory, L. V. Cundiff, R. M. Koch
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Least squares means, genetic (σg), and phenotypic (σp) standard deviations, and phenotypic coefficients of variation (CV) were estimated on an age-constant basis for growth, carcass, and meat traits of castrate males from 12 breed groups combined, for 9 purebreds combined, and for the F3 generation of three composite populations combined to which the nine purebreds contributed. Also, heritabilities ( h2) and genetic ( rg) and phenotypic ( rp) correlations were estimated among growth, carcass, and meat traits for all breed groups combined involving 1,594 individuals that were the progeny of …
Symposium On The Phyllochron: Importance Of The Phyllochron In Studying Development And Growth In Grasses, Wallace Wilhelm, Gregory S. Mcmaster
Symposium On The Phyllochron: Importance Of The Phyllochron In Studying Development And Growth In Grasses, Wallace Wilhelm, Gregory S. Mcmaster
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
The phyllochron, which is defined as the interval between similar growth stages of successive leaves on the same culm, has been used extensively to describe and understand development of grasses. The purpose of this paper is to introduce seven papers presented as part of the symposium Understanding Development and Growth in Grasses: Role of the Phyllochron Concept. Environmental (temperature, water, and day length) factors and genetics affect the duration of the phyllochron. The following seven papers broaden the discussion of these topics and present new concepts about how the environment and genetics impact the relationship between leaf appearance and …
Local Action Of Trophoblast Interferons In Suppression Of The Development Of Oxytocin And Oestradiol Receptors In Ovine Endometrium, G. E. Lamming, D. C. Wathes, A. P. F. Flint, J. H. Payne, K. R. Stevenson, J. L. Vallet
Local Action Of Trophoblast Interferons In Suppression Of The Development Of Oxytocin And Oestradiol Receptors In Ovine Endometrium, G. E. Lamming, D. C. Wathes, A. P. F. Flint, J. H. Payne, K. R. Stevenson, J. L. Vallet
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Luteolysis in sheep is associated with uterine secretion of pulses of prostaglandin F2α(PGF2α) due to the action of luteal oxytocin on endometrial oxytocin receptors. For pregnancy to become established inhibition of oxytocin receptors is important as an antiluteolytic mechanism. The maternal recognition of pregnancy in cattle and sheep involves production, by the trophoblast, of a type 1 interferon (IFN-τ)that suppresses uterine development of oxytocin receptors and the generation of luteolytic episodes of PGF2α. The action of IFN-τ in surgically prepared unilaterally pregnant ewes was investigated. Finn-Dorset ewes were anaesthetized on day 6 or 7 …