bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corn Morphology, Mass, and Grain Yield as Affected by Early‐Season Red: Far‐Red Light Environments
Authors: Markham Melinda Y. , Stoltenberg David E. 
Published: January 2010

ABSTRACTThe spatial arrangement among plants affects both vegetative and reproductive meristem development. More axillary meristems develop at lower plant densities, which are associated with relatively high red:far‐red light ratios (R:FRs; 645:735 nm). However, little is known about the effect of R:FR on corn (Zea maysL.) productivity. We conducted field research to determine the effect of early‐season (VE–V7 corn) R:FR environments on corn morphology and productivity. Low, control, and high R:FR treatments were established by varying corn plant density (107,600, 53,800, and 3000 plants ha−1, respectively). At canopy closure (V7 corn), R:FR in the low, control, and high R:FR treatments was 0.23, 0.49, and 0.99, respectively. Each treatment was subsequently thinned to 3000 plants ha−1to avoid confounding effects of R:FR treatments and shading among plants. Grain yield per plant in the high R:FR treatment was 1.5 and 2.0 times greater than in control and low R:FR treatments, respectively, across years. Greater yield in the high R:FR treatment was attributed to greater tiller grain yield. Soil moisture and nutrient availability were similar among R:FR treatments. These results indicate that early‐season R:FR was an important factor affecting corn productivity. Greater understanding of the R:FR‐dependent pathway that controls axillary meristem development may provide direction for increasing productivity of elite nonprolific corn genotypes.
Vegetative Phase Change Characteristics and Resistance to Common Rust of Corn Cultivars Developed in Different Eras
Authors: Riedeman E. S. , Tracy W. F. 
Published: January 2010

ABSTRACTSince 1930, maize (Zea mays L.) yields in the United States have increased more than fourfold. Previous studies examining maize cultivars grown during that period have documented changes in yield, leaf angle, tassel size, drought tolerance, and insect resistance, but none have examined changes in vegetative phase change or resistance to common rust (Puccinia sorghi Schwein.). Vegetative phase change has been shown to affect both disease and insect resistance, and common rust can reduce yields in maize especially east of the Mississippi River. Thirty‐six widely used northern Corn Belt cultivars spanning the years of pre‐1930 to 2006 were evaluated for phase change traits and rust resistance. Cultivars were divided into early and late maturity groups from different eras and planted at two locations with two planting dates per location for 2 yr. Timing of vegetative phase change has not changed linearly over the eras examined. There was, however, a significant linear increase in rust resistance over that time. In the early maturity group, percentage of leaf area infected by rust was found to decrease at a rate of 0.1% yr−1 Whole‐plant rust resistance in the late maturity group was found to increase at a rate of 0.05% yr−1.
A Model to Predict Diurnal Pollen Shed in Maize
Authors: Viner Brian J. , Westgate Mark E. , Arritt Raymond W. 
Published: January 2010

ABSTRACTWe have developed a mathematical model to predict the diurnal pattern of maize (Zea mays L.) pollen shed on the basis of local meteorological conditions. Our goal is to improve simulations of maize pollen dispersion that have typically released pollen at a constant rate in contrast with measurements of pollen shed that show diurnal variation in the rate of shed. Measurements coupling pollen shed and local meteorological variables were made during controlled experiments and a 2004 field experiment to examine the influence of meteorological conditions on pollen shed. From these data, a model was developed to predict the diurnal pattern of pollen shed as a function of vapor pressure deficit, solar radiation, temperature, and the amount of pollen remaining to be shed. The model was validated by predicting the rate of pollen shed, normalized by the daily total of pollen shed, that occurred hourly for days during a 2003 field study () and results from van Hout et al. (2008; ). The model captured the general trend of pollen shed and predicted the time of peak shed within an hour of the measured peak on most days. The model, however, tended to underpredict the magnitude of the normalized peak rate of shed and did not account for secondary peaks in pollen shed that were occasionally observed. Thus, future model refinements will depend on identifying additional biological or environmental factors that impact the instantaneous rate of pollen shed.
Green Tea Catechins Applied to Susceptible Hosts Inhibit Parasitic Plant Attachment Success
Authors: Lewis Kristin C. , Alers‐García Janice , Wright Leslie J. 
Published: January 2010

ABSTRACTParasitic plants utilize cell wall degrading enzymes (CWDEs) to penetrate their host plant and attach to host vasculature. Inhibition of CWDEs may confer resistance on susceptible hosts, offering a strategy for parasitic plant control. Here, exogenous application of green tea catechins, which inhibit pectin methylesterase (a CWDE), was used to delay parasitic plant attachment. Texas bluebonnet (Lupinus texensisHook.) was grown with its naturally occurring root hemiparasite, Texas paintbrush (Castilleja indivisaEngelm.). Catechins, fertilizer (ammonium nitrate), or water were added to soil twice weekly. Parasite attachment was detected using Dragendorff reagent. Effects on growth and germination were also assessed. Parasite attachment to the host was prevented by 5 g L−1of catechins through 20 d and reduced through 36 d after parasite seedling addition. Five grams per liter of catechins delayed germination in Texas bluebonnet but not in Texas paintbrush. To test the effects of CWDE inhibitors on aboveground parasitism,Arabidopsis thaliana(L.) Heynh. seedlings were grown with field dodder (Cuscuta pentagonaEngelm.), a promiscuous shoot holoparasite. Ten grams per liter of catechins applied to theA. thalianashoot surface inhibited field dodder attachment, although prehaustorial development was not affected. Our findings corroborate existing evidence that CWDE inhibition is a critical component of natural resistance to parasitic plants and open a new area of research into the use of exogenous CWDE inhibitors to control parasitic plant attachment.
Validation of Molecular Markers Associated with Net Blotch Resistance and Their Utilization in Barley Breeding
Authors: Grewal Tajinder S. , Rossnagel Brian G. , Scoles Graham J. 
Published: January 2010

ABSTRACTWith the advancement of molecular marker technology and computer software, mapping quantitative trait loci (QTL) for complex traits in agricultural crops is frequent; however, exploitation of these QTL in practical breeding programs is limited. Here we report the validation of molecular markers linked to net blotch resistance QTL and their utilization in a barley (Hordeum vulgare L.) breeding program. Barley net blotch, caused by Pyrenophora teres Drechs. [anamorph: Drechslera teres (Sacc.) Shoemaker], is a serious foliar disease in Canada and other parts of the world. Simple sequence repeat (SSR) markers linked to net‐form net blotch (NFNB) resistance QTL (QRpt6) and spot‐form net blotch (SFNB) resistance QTL (QRpts4) were validated in two barley populations unrelated to the original mapping population. Marker‐assisted selection (MAS) was performed with SSR markers to select resistant and susceptible lines in two other populations. The lines homozygous for the resistant‐parent alleles at both marker loci had significantly lower infection than lines homozygous for the susceptible‐parent alleles at both markers, indicating that MAS for net blotch resistance is practical. Since the major QTL, QRpt6, may provide adequate NFNB field resistance in western Canada, the plan for the Crop Development Centre (CDC) barley breeding program is to routinely utilize MAS for QRpt6 followed by normal field screening in disease nurseries to select the most resistant lines having additional resistance provided by less critical genes associated with other identified QTL. The CDC program has implemented routine MAS for QRpt6 and recommends this approach to other barley breeding programs.
Seed Yield, Development, and Variation in Diverse Poa pratensis Accessions
Authors: Johnson R. C. , Johnston W. J. , Bertoli F. B. , Golob C. T. 
Published: January 2010

ABSTRACTPost‐harvest residue removal is critical for high seed production of Kentucky bluegrass (Poa pratensis L.). Previous work showed some accessions have little yield reduction with mechanical removal of post‐harvest residue compared with the controversial practice of open‐field burning. Using 10 of these accessions, our objectives were (i) to relate seed yield and yield components in spaced plants to yield in row‐seeded plots, (ii) to link yield to growth and development factors, and (iii) to determine variation for seed production factors among accessions. Seed yield, seeds per panicle, panicle number, weight per seed, heading, anthesis, and harvest dates showed strong accession differences on spaced plants in 2002 and 2003. Yields in row‐seeded plots from 1998 and 1999 data were consistently correlated with yield per plant per area in spaced plants in 2002 (r = 0.75, P < 0.05) and 2003 (r = 0.90, P < 0.01). Turf quality was negatively correlated with yield per plant per area in 2002 and 2003 but was not consistently correlated with yield components. Days from heading to anthesis consistently correlated with yield per plant per area in 2002 (r = 0.81, P < 0.01) and 2003 (r = 0.85, P < 0.01). Variation for seed yield and yield components was observed within accessions both years and differed among accessions. The results show that seed yield per plant per area in spaced plants may be a useful predictor of yield in field stands and that a long heading to anthesis period promotes seeds per panicle and seed yield.
Molecular Mapping of Wheat Leaf Rust Resistance Gene Lr42
Authors: Sun Xiaochun , Bai Guihua , Carver Brett F. , Bowden Robert 
Published: January 2010

ABSTRACTLeaf rust, caused by Puccinia triticina Eriks., is an important foliar disease of wheat (Triticum aestivum L.) worldwide. Leaf rust resistance gene Lr42 from Aegilops tauschii Coss. has been used as a source of rust resistance in breeding programs. To identify molecular markers closely linked to Lr42, a segregating population of near‐isogenic lines contrasting for the presence of Lr42 was developed in the hard winter wheat cultivar Century background and evaluated for rust infection type at both seedling and adult‐plant stages. Simple sequence repeat (SSR) markers were screened using bulked‐segregant analysis. Two markers closely linked to Lr42 were identified on chromosome 1DS. The closest marker, Xwmc432, is about 0.8 cM from Lr42. Physical mapping of both SSR markers using Chinese Spring nullitetrasomic and ditelosomic genetic stocks confirmed that the markers linked to Lr42 were on 1DS. Markers for Lr42 were highly polymorphic between parents and among a diverse set of wheat germplasm collected from several countries, indicating that these markers are useful for marker‐assisted selection for Lr42.
Feasibility of Seed Production from Nonflowering Orchardgrass
Authors: Casler M. D. , Johnson R. C. , Barker R. E. , Jenderek M. M. , Papadopoulos Y. A. , Cherney J. H. 
Published: January 2010

ABSTRACTNonflowering or sparse flowering orchardgrass (Dactylis glomerata L.) would greatly simplify management of intensive rotational grazing systems. Our objective was to quantify seed production on nonflowering orchardgrass clones selected in cold‐winter climates, but grown for seed in mild‐winter climates. We evaluated 98 orchardgrass clones for seed production traits at four locations. Most plants (∼92%) flowered at the three northern locations, but only 38% flowered at Parlier, which may have a winter insufficiently cold for adequate floral induction and vernalization. Mean panicle number was lowest (11%) for plants selected at the location with the warmest winter conditions, and highest (37%) for plants selected at the location with the coldest winter conditions. These results confirm our expectations that the most desirable plants (nonflowering under cold winters and normal flowering under mild winters) should arise from selection under more severe winters. Selection for nonflowering under mild winter conditions simply leads to nonflowering plants under all conditions. These results demonstrate that individual orchardgrass genotypes are capable of dual phenotypic expression, flowering in mild‐winter climates or expressing the nonflowering trait in cold‐winter climates and that the expression of this trait depends on both the selection and evaluation location.
Response of Oat Genotypes to Fusarium Head Blight in Eastern Canada
Authors: Yan Weikai , Fregeau‐Reid Judith , Rioux Sylvie , Pageau Denis , Xue Allen , Martin Richard , Fedak George , de Haan Brad , Lajeunesse Julie , Savard Marc 
Published: January 2010

ABSTRACTRecent investigations in northern Europe and western Canada suggested that mycotoxins caused by Fusarium head blight (FHB) could be a potential problem for oat (Avena sativa L.) production and oat food safety. Here we report studies conducted in eastern Canada to address this issue. In one study, oat genotypes of diverse origin were evaluated for grain and groat deoxynivalenol (DON) contamination owing to artificial FHB inoculation at Ottawa, ON, in 2006 and 2007. In a separate study, oat genotypes tested in the yearly Quebec Oat Registration and Recommendation Trials were evaluated for DON contamination due to artificial inoculation in Quebec from 2003 to 2008. Deoxynivalenol was detected in all tested genotypes, and up to 43 μg g−1 of DON was observed in the oat grain. Up to 86% of the DON in the oat grain was removed by dehulling. However, some genotypes still retained up to 9 μg g−1 of DON in the groat. Genotype ranking in DON content was relatively consistent across years, planting dates, and experiments, and genotypes with consistently low and high DON levels were identified. It was concluded that FHB is a potential problem for oat production and oat food safety under high FHB pressures; however, the severity of this problem needs to be further assessed by extensive monitoring of the DON level under natural conditions. The most susceptible genotypes identified in this study can be useful for this purpose.
Probability of Yield Response to Inoculants in Fields with a History of Soybean
Authors: De Bruin J. L. , Pedersen P. , Conley S. P. , Gaska J. M. , Naeve S. L. , Kurle J. E. , Elmore R. W. , Giesler L. J. , Abendroth L. J. 
Published: January 2010

ABSTRACTInoculants containing Bradyrhizobium japonicum are available for soybean [Glycine max (L.) Merr.] production but may not be necessary in fields where soybean previously has been produced. The objective of this study was to determine yield response and probability of an economic return from inoculants in fields with a recent history of soybean production. Fifty‐one inoculant products were evaluated in experiments (n = 73) conducted in Indiana, Iowa, Minnesota, Nebraska, and Wisconsin between 2000 and 2008. Inoculant products were similar and did not produce a yield response relative to an untreated control different from zero (P > 0.05) at 63 environments. Probability for a break‐even economic return at a soybean sale price of $0.33 kg−1 was 59% for Nebraska, 36% for Wisconsin, 25% for Minnesota, 25% for Indiana, and 4% for Iowa. Attaining a return on investment of 67 kg ha−1 (a 2:1 return) reduced success to 11, 2, 1, 7, and 0.2%, for the five states, respectively. Data from this range of environments and products indicate that application of an inoculant offers limited success for either a yield increase or improved economic return on soils where soybean has previously been grown in the upper Midwest.
Genotypic Variation in Peanut for Transpiration Response to Vapor Pressure Deficit
Authors: Devi M. Jyostna , Sinclair Thomas R. , Vadez Vincent 
Published: January 2010

ABSTRACTConservation of soil water resulting from decreases in stomata conductance under atmospheric high vapor pressure deficit (VPD) conditions is a possible approach for enhanced tolerance of water deficit by crops. Water deficit is usually a concern in peanut (Arachis hypogea L.) since it is frequently grown on sandy soils with low water‐holding capacity. Seventeen peanut genotypes were studied to determine the response of their transpiration rates (TR) to VPD. The results of this study demonstrated variation among peanut genotypes with nine genotypes exhibiting a breakpoint in their VPD response at about 2.2 kPa, above which there was little or no further increase in TR. Therefore, these genotypes with a breakpoint have the possibility of soil water conservation when VPD exceeded 2.2 kPa. The remaining eight genotypes had a linear response in TR over the whole range of tested VPD. Also, the 17 genotypes could be separated into groups with differing rates of increasing TR at low VPD. The change in TR with increasing VPD may be important in determining the rate at which soil water is used under field conditions.
Mineralization of teeth and bones of the cave bear (Ursus spelaeus) from the Biśnik Cave, Southern Poland
Authors: Rogóż Anna , Sawłowicz Zbigniew , Socha Paweł , Stefaniak Krzysztof 
Published: January 2010

Mineralization of teeth and bones of the cave bear (Ursus spelaeus) from the Biśnik Cave, Southern PolandThe studied bones and teeth of the cave bear (Ursus spelaeus) come from the Biśnik Cave, located in the Częstochowa Upland (Southern Poland). The specimens originate from different geological layers formed since the Odra Glaciation (250-270 thousand years BP). The fossilized bones and teeth were studied using optical microscopy, scanning electron microscopy, X-ray diffraction, FTIR spectroscopy, and INAA. They are built of recrystallized carbonate-rich apatite-(CaOH) and/or apatite-(CaOH). The teeth additionally contain some apatite-(CaF). The lack of collagen and minor REE contents suggest rapid burial and collagen decay in the early stage of diagenesis. The bones and teeth have only limited mineral infillings. In some teeth, Mn-Fe (hydroxy)oxides were found in the dentine canaliculi and in bones, some osteocyte lacunae contain Fe (hydroxy)oxides with admixture of Mn. In one bone specimen, calcite infillings are present in Haversian canals. The infillings formed during later stages of diagenesis and were succeeded by non-filled cracks.
Serum Levels and in Vitro Production of Th1- and Th2-Type Cytokines by Peripheral Blood Mononuclear Cells in Patients Suffering from Systemic Lupus Erythematosus
Authors: Đorđević Vidosava , Zvezdanović Lilika , Ćosić Vladan , Vlahović Predrag , Kundalić Slavica , Jevtović-Stoimenov Tatjana , Stamenković Bojana , Mitrović Dragoslav 
Published: January 2010

Serum Levels and in Vitro Production of Th1- and Th2-Type Cytokines by Peripheral Blood Mononuclear Cells in Patients Suffering from Systemic Lupus ErythematosusTh1-type and Th2-type cytokine profiles and adhesion molecules in the serum of patients suffering from systemic lupus erythematosus and the cytokine production by peripheral blood mononuclear cells (PBMC) were studied. Tumor necrosis factor-alpha (TNF-α), interferongamma (IFN-γ), interleukin-1β (IL-1β), IL-4, IL-10, IL-13, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were measured using ELISA technique in the sera of 16 systemic lupus erythematosus patients without vasculitis (SLE), 30 SLE patients with vasculitis (LV), and in 18 healthy controls. The cytokines were also measured in the culture media of unstimulated, concana valin-A (Con-A) and phorbol-12-myristate-13-acetate (PMA) stimulated PBMC. TNF-α serum levels were significantly elevated in both SLE and LV patients and those of IL-1β in SLE patients. TNF-α was also significantly increased in SLE compared to LV patients. Serum levels of all three Th-2 cytokines were significantly elevated in both SLE and LV patients compared to healthy controls. Serum IFN-γ and Th2 cytokine levels were significantly increased in patients with more active disease. Both ICAM-1 and VCAM-1 were significantly increased in SLE patients and only VCAM-1 in LV patients. ICAM-1 showed a significant correlation with IL-1β, IFN-γ, IL-4 and IL-10 in both patient groups. In the SLE group VCAM-1 correlated significantly only with ICAM-1, but in the LV group only with IL-1β and IFN-γ. Compared to healthy controls, basal TNF-α and IL-4 production by unstimulated PBMC derived from SLE patients were significantly increased. Con-A-stimulated PBMC of both SLE groups produced significantly more IFN-γ, IL-4 and IL-13 than Con-A-stimulated control cells. Con-A-stimulated cells derived from LV patients produced much more INF-γ than cells from SLE patients. PMA strongly stimulated INFγ, TNFα and IL-13 production by cells derived from both SLE groups but had no effect on IL-4 production. In addition, it had little if any effect on the production of INFγ and IL-13 by PBMC derived from healthy donors. These findings suggest that the altered pattern of cytokine production by PBMC may play an important role in the SLE pathophysiology, accounting for differences in the clinical expression of the disease. The differences in adhesion molecules production and their correlation with cytokines suggest ICAM-1 and VCAM-1 as useful markers in SLE patients stratification.
Molecular, genetic and epigenetic pathways of peroxynitrite-induced cellular toxicity
Authors: Korkmaz Ahmet , Oter Sukru , Seyrek Melik , Topal Turgut 
Published: January 2010

Molecular, genetic and epigenetic pathways of peroxynitrite-induced cellular toxicityOxidative stress plays a key role in the pathogenesis of cancer and many metabolic diseases; therefore, an effective antioxidant therapy would be of great importance in these circumstances. Nevertheless, convincing randomized clinical trials revealed that antioxidant supplementations were not associated with significant reduction in incidence of cancer, chronic diseases and all-cause mortality. As oxidation of essential molecules continues, it turns to nitro-oxidative stress because of the involvement of nitric oxide in pathogenesis processes. Peroxynitrite damages via several distinctive mechanisms; first, it has direct toxic effects on all biomolecules and causes lipid peroxidation, protein oxidation and DNA damage. The second mechanism involves the induction of several transcription factors leading to cytokine-induced chronic inflammation. Finally, it causes epigenetic perturbations that exaggerate nuclear factor kappa-B mediated inflammatory gene expression. Lessons-learned from the treatment of several chronic disorders including pulmonary diseases suggest that, chronic inflammation and glucocorticoid resistance are regulated by prolonged peroxynitrite production.