bluuebunny/crossref_metadata_2025 huggingface dataset:
Microsatellite Marker Characterization of Chilean Common Bean (Phaseolus vulgaris L.) Germplasm
Authors: Viviana Becerra V. , Mario Paredes C. , Carmen Rojo M. , Díaz Lucy M. , Blair Matthew W.
Published: August 2010

The Chilean national common bean germplasm collection consists of 1200 accessions, most of which have not been characterized or used in breeding programs. As part of the characterization of this germplasm we have formed a core collection of 246 accessions that represent 21% of the whole collection and that consists of many race Chile representatives as well as varieties from other races that are traditionally grown in the country. The specific objectives of this work were to use microsatellites to evaluate the level of polymorphism in the Chilean core collection and to determine the genetic variability of race Chile and its relationships with other races. The results indicate that the level of polymorphism detected with microsatellites was higher than that obtained with previous molecular or biochemical markers. The number of microsatellite alleles varied from 2 to 14 and the polymorphism information content (PIC) values were 0.08 to 0.84. Heterozygosity ranged from 0 to 0.052 for each of the markers. Euclidean genetic distance ranged from 0.12% between race Chile and race Nueva Granada to 0.71% between race Chile and race Mesoamerica. Multiple correspondence analysis (MCA) showed clustering of the accessions into the two main genepools, with race Chile genotypes grouping mainly with race Nueva Granada genotypes.
Prediction of Forage Quality from Remotely Sensed Data: Comparison of Cultivar‐Specific and Cultivar‐Independent Equations Using Three Methods of Calibration
Authors: Starks Patrick J. , Brown Michael A.
Published: August 2010

Remote sensing of pasture canopies could reduce laborious field sampling procedures and provide timely information to ranch and livestock managers. This study evaluated partial least squares (PLS) regression, multiple linear regression with maximum r2 improvement (MAXR), and artificial neural networks (ANN) for development of robust equations (i.e., cultivar‐independent [CI]) to predict concentrations of nitrogen (N), neutral detergent fiber (NDF), and acid detergent fiber (ADF) from hyperspectral remotely sensed reflectance data collected from six cultivars of live bermudagrass canopies. Specific study objectives were to: i) develop both cultivar‐independent and cultivar‐specific (CS) equations to predict N, NDF, and ADF from remotely sensed canopy reflectance, ii) validate the accuracy of these equations on a independent data set, iii) compare the results from the CS and CI equations to determine how well equations developed across cultivar perform relative to equations developed for a specific cultivar of bermudagrass, and iv) compare contributing wavelengths across calibration method.
Heterosis in Sweet Sorghum and Selection of a New Sweet Sorghum Hybrid for Use in Syrup Production in Appalachia
Authors: Pfeiffer T. W. , Bitzer M. J. , Toy J. J. , Pedersen J. F.
Published: August 2010

Although heterosis is well established in grain and forage sorghum [Sorghum bicolor (L.) Moench], reports of heterosis in sweet sorghum are limited to results from grain sorghum × sweet sorghum hybrids. Recent development of cytoplasmic male‐sterile sweet sorghum lines allows creation of sweet sorghum hybrids for research and industry. Male sterility may also affect allocation of photosynthate to plant parts, creating the potential to increase sugar content in stems by eliminating seed as a sink. The objectives of this study were to compare performance of A3 cytoplasmic male‐sterile lines and A3 cytoplasmic male‐sterile hybrids to fertile B3 counterparts and to each other. A3 cytoplasmic male‐sterile ‘Dale’, ‘Wray’, ‘Sugar Drip’, and N100 were crossed in all combinations to their male‐fertile counterparts, resulting in 20 genotypes including the male‐fertile lines. The 20 genotypes were grown in a randomized complete block in 2004 and 2005 at Lexington, KY. Male‐sterile hybrids and lines had higher brix than male‐fertile lines. Hybrids produced greater stalk yield due to taller plants with greater stem diameter. Juice fraction and juice composition remained relatively unchanged. Only six hybrids showed positive heterosis for brix. The greater juice yield and higher sugar content of selected hybrids such as A3 N100 × Dale could produce more total syrup or ethanol than current pure‐line sweet sorghum varieties.
Influence of Locations and Planting Dates on Protein Composition of Soybean Lines with Modified Beta‐Conglycinin and Glycinin Concentration
Authors: Jenkinson Jonathan E. , Fehr Walter R.
Published: August 2010

Soybean [Glycine max (L.) Merr.] cultivars with increased β‐conglycinin (BC) and reduced glycinin (Gly) may have both food production and human health benefits. The stability of BC and Gly concentrations over different environmental conditions will be an important factor in the production of these cultivars. The objective of this study was to evaluate the effect of locations and planting dates on the protein composition of soybean genotypes with varied combinations of Gy and gy alleles for reduced Gly and increased BC concentration. Six soybean lines with different gy allele combinations and one common cultivar with only wild‐type Gy alleles were grown at four locations with three planting dates at each location in 2008. There were no significant differences among planting dates for the mean concentration of BC, Gly, or their subunits. The means of locations were significantly different for all of the protein components, except for the A124 subunit of Gly. The genotype with four gy alleles produced 0 g kg−1 of Gly across locations and planting dates, but only three of the mutant gy alleles were required to maximize BC concentration. Grain produced at different locations likely would differ in BC and Gly concentration, but planting dates at a location would not be expected to significantly affect the protein components.
Genetic Analysis of Heat Tolerance at Anthesis in Rice
Authors: Jagadish S. V. K. , Cairns J. , Lafitte R. , Wheeler T. R. , Price A. H. , Craufurd P. Q.
Published: August 2010

Genetic analysis of heat tolerance will help breeders produce rice (Oryza sativa L.) varieties adapted to future climates. An F6 population of 181 recombinant inbred lines of Bala (tolerant) × Azucena (susceptible) was screened for heat tolerance at anthesis by measuring spikelet fertility at 30°C (control) and 38°C (high temperature) in experiments conducted in the Philippines and the United Kingdom. The parents varied significantly for absolute spikelet fertility under control (79–87%) and at high temperature (2.9–47.1%), and for relative spikelet fertility (high temperature/control) at high temperature (3.7–54.9%). There was no correlation between spikelet fertility in control and high‐temperature conditions and no common quantitative trait loci (QTLs) were identified. Two QTLs for spikelet fertility under control conditions were identified on chromosomes 2 and 4. Eight QTLs for spikelet fertility under high‐temperature conditions were identified on chromosomes 1, 2, 3, 8, 10, and 11. The most significant heat‐responsive QTL, contributed by Bala and explaining up to 18% of the phenotypic variation, was identified on chromosome 1 (38.35 mega base pairs on the rice physical genome map). This QTL was also found to influence plant height, explaining 36.6% of the phenotypic variation. A comparison with other studies of abiotic (drought, cold, salinity) stresses showed QTLs at similar positions on chromosomes 1, 3, 8, and 10, suggesting common underlying stress‐responsive regions of the genome.
Maternal Effects on Fatty Acid Composition of Soybean Seed Oil
Authors: Gilsinger J. J. , Burton J. W. , Carter T. E.
Published: August 2010

The success of genetically altering the fatty acid composition of soybean (Glycine max (L.) Merr.) seed oil is determined by the rate of genetic gain through selection. Maternal effects can influence genetic gain. Objectives of this study were to investigate the presence and magnitude of maternal effects on fatty acid content of soybean oil. Maternal effects for unsaturated fatty acid content were evaluated over 2 yr using reciprocal F1 soybean seed from crosses between the mid‐oleic/low‐linolenic line ‘N98‐4445A’ and six cytoplasmically diverse cultivars. Maternal effects were significant across genetically diverse materials and likely the result of the phenotype of the maternal plant. The magnitude of the maternal effect was typically less when N98‐4445A was used as the maternal parent. These data suggest that selection based on the oil composition of single F2 seeds might be ineffective but less so if the altered fatty acid parent is the maternal parent. Maternal effects on saturated fatty acid content were evaluated both in the field and in vitro using reciprocal F1 soybean seed from the cross between the high‐palmitic line ‘N02‐4441’ and ‘Dare’. Maternal effects were significant when grown in the field. When reciprocal F1 and parental 25 d old embryo seeds were grown in vitro, maternal effects between reciprocal crosses were not apparent, while significant differences between the parents were maintained. This suggests that factors translocated from the maternal plant may be causing the maternal effect on developing F1 seeds.
Testcross Response to Four Cycles of Half‐sib and S2 Recurrent Selection in the BS13 Maize (Zea mays L.) Population
Authors: Edwards Jode
Published: August 2010

Inbred progeny recurrent selection has been shown to be theoretically superior to several forms of noninbred‐progeny recurrent selection. However, recent improvements to theory and empirical evidence suggest that inbred‐progeny recurrent selection is not a superior method of recurrent selection. In the BS13(S) population, inbred‐progeny recurrent selection has not been effective at improving population per se performance. However, no other selection programs have been evaluated in BS13(S), so there is no basis to compare inbred‐progeny recurrent selection in BS13(S) to other methods to determine if other methods might be more effective. Four cycles of half‐sib selection with inbred line B97 as tester have been completed. The first four cycles of half‐sib selection and first four cycles of inbred‐progeny selection were testcrossed to B97 and evaluated in a replicated experiment in 2007 and 2008. Half‐sib selection improved grain yield, grain moisture, stalk lodging, root lodging, test weight, and final plant density, whereas inbred‐progeny selection did not improve any of these traits. This study adds to growing empirical literature suggesting that inbred‐progeny recurrent selection is inferior to noninbred‐progeny selection methods. A hypothesis has been put forth that pseudo‐overdominance caused by linkage disequilibrium may have limited response to inbred‐progeny recurrent selection in BS13(S) as well as other maize populations.
Dairy Manure Compost Application Rate and Timing Influence Bermudagrass Yield and Nutrient Concentration
Authors: Muir James P. , Butler Twain , Helton Thomas J. , McFarland Mark L.
Published: August 2010

Management strategies for applying composted dairy manures on perennial forages are not well defined. We researched compost application timing and rate with and without supplemental inorganic nitrogen on ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.]. Treatments were 18, 36, and 72 Mg ha−1 dry dairy compost rates (supplying 112, 224, and 448 kg N ha−1) applied in November, January, or March and supplemented with 0 or 112 kg ha−1 inorganic N fertilizer as ammonium nitrate after each harvest. The addition of compost increased (P < 0.05) yield compared with no‐compost plots the first year, but the benefits were only measureable at the 72 Mg rate by the second year. Waiting to apply compost until March resulted in 26% greater (P < 0.05) yields the first year at the 72 Mg compost rate, 15% at the 36 Mg rate, and 17% at the 18 Mg rate compared with the January applications at the same rates. November compost application resulted in greater uptake of compost‐phosphorus by plants, March dates improved compost‐potassium uptake, while grass N uptake was independent of application date. On composted plots, plant N and K concentration increases were discernable in early harvests, while P increases were apparent in subsequent harvests compared with no compost. Supplemental N increased dry matter (DM) and P yields. Results indicated that compost application dates and amounts change P uptake rates or inorganic fertilizer N efficiency.
Plant Breeding and Rural Development in the United States
Authors: Woeste Keith E. , Blanche Sterling B. , Moldenhauer Karen A. , Nelson C. Dana
Published: August 2010

Plant breeders contributed enormously to the agricultural and economic development of the United States. By improving the profitability of farming, plant breeders improved the economic condition of farmers and contributed to the growth and structure of rural communities. In the years since World War II, agriculture and the quality of rural life have been driven by policies that encouraged and subsidized an agroindustrial production model. Plant breeders responded by developing methods and deploying products attuned to agroindustrial clients. Major achievements by plant breeders of the era include the development of higher‐yielding crops suitable to new environments and mechanized harvesting and shipping. As social, technological, and economic changes reinforced the expansion and dominance of the agroindustrial model, rural communities sustained high levels of out‐migration. At the same time, a variety of societal and economic forces have encouraged new food system models, including the locavores and community‐supported agriculture. Sustainability indices reflect the desire of megaretailers to make the relationship between consumers and the production of their food more transparent. These forces, along with an increased focus on the quality of rural life in America, represent opportunities for plant breeders to address the needs of new clients, to develop methods appropriate to their client's values, and to serve traditional clients in new ways.
The Relationship between Coverage and Dry Matter Contribution of Forage Legumes in Binary Legume–Grass Mixtures
Authors: Himstedt Maike , Fricke Thomas , Wachendorf Michael
Published: August 2010

An efficient and accurate detection of the contribution of legume dry matter (DM) in legume–grass mixtures is of great importance for a targeted management of legume‐based swards. Legume coverage is a frequently used parameter to describe the dominance structure in vegetation because it is easily accessible. The present study investigates the relationships between legume coverage and different legume species and growth stages. A dataset was generated from a pot experiment that was conducted under controlled conditions across a wide range of legume species (Trifolium repens L., T. pratense L., Medicago sativa L.), proportions of legumes (0–800 g kg−1), and growth stages (tillering to heading). Multiple regression analysis revealed a positive relationship between legume contribution and coverage for the separate legume species (R2 = 0.98–0.99), as well as for the combined dataset including all legumes (R2 = 0.98). Total biomass was related to clover coverage in a complex manner, reducing legume contribution by up to 180 g kg−1 with an increase of total biomass from 300 to 1500 kg DM ha−1 The validation of the models with mixed swards of grass and either white or red clover that were grown in the field showed good results (r2 = 0.98).
Relative Cattle Preference of 24 Forage Kochia (Kochia prostrata) Entries and Its Relation to Forage Nutritive Value and Morphological Characteristics
Authors: Waldron Blair L. , Davenport Burke W. , Malechek John C. , Jensen Kevin B.
Published: August 2010

Forage kochia [Kochia prostrata (L.) Schrad.] has been shown to be nutritious fall and winter forage on western U.S. rangelands; however, its utilization by livestock is not well understood. This study compared relative cattle preferences among forage kochia accessions, alfalfa (Medicago sativa L.), and winterfat (Krascheninnikovia spp.), and how they related to nutritional and morphological characteristics. Relative preference was measured as biomass consumed on experimental plots near Promontory, UT, during September of 2002 and 2003. Preference differences (P < 0.01) were found among forage kochia accessions; however, all were consumed to some level, ranging from 71 to 35% of biomass consumed. Traits highly associated with biomass consumed included pregrazing biomass (r = 0.93), phenological maturity (r = −0.85), branch density (r = 0.80), and leafiness (r = 0.70) suggesting that productive, leafy, less mature plants are preferred by cattle. Crude protein, fiber, and digestibility were moderately associated with cattle preference but were not consistent predictors. Overall, we conclude that forage kochia is a palatable shrub for grazing during the fall, with preference and utilization of some entries being comparable to alfalfa and greater than winterfat. Grazing behavior also suggested that forage kochia growing in a mixture with adapted grasses would enhance livestock utilization.
Moisture Deficit and Defoliation Effects on White Clover Yield and Demography
Authors: García J. A. , Piñeiro G. , Arana S. , Santiñaque F. H.
Published: August 2010

Moisture stress and high temperatures during the summer are major factors limiting white clover (Trifolium repens L.) productivity in Uruguay. Our objective was to determine the influence of irrigation and defoliation on the growth of white clover. Two white clover cultivars were sown with tall fescue [Schedonorus arundinaceus (Schreb.) Dumort = Lolium arundinaceum (Schreb.) Darbysh.] and subjected to three defoliation regimes with and without low volume irrigations during the summer. Dry matter (DM) yield, botanical composition, number of stolons, and volunteer seedlings were recorded for 3 yr. Irrigation was the main factor affecting clover growth. Clover yields under irrigation were 5.0, 7.4, and 6.9 Mg DM ha−1 in the first, second, and third year compared with 3.0, 5.1, and 1.6 Mg DM ha−1 for the same years in the nonirrigated swards. Defoliation frequency did not affect pasture yields in the nonirrigated swards but the more frequent defoliation produced higher yields under irrigation after the second year. Deferring defoliation during summer did not improve clover yield or persistence. Stolons increased during autumn and winter and decreased in spring and summer. White clover declined after the second summer in the nonirrigated swards while irrigation maintained good clover stand and yield. Profuse seedlings emergences were observed but only 1% survived, suggesting that they were not a reliable mechanism for persistence. Successful reseeding occurred only at the end of the experiment after a severe drought followed by a long wet season.
Candidate Genes within Tissue Culture Regeneration QTL Revisited with a Linkage Map Based on Transcript‐Derived Markers
Authors: Tyagi Neerja , Dahleen Lynn S. , Bregitzer Phil
Published: August 2010

Green plant regeneration from tissue culture is under the genetic control of multiple genes. Candidate genes for regeneration have been identified in multiple species using quantitative trait loci (QTL) and microarray analyses, and some of these genes have been verified as improving regeneration through transformation. Multiple studies have located QTL for regeneration from barley (Hordeum vulgare L.) tissue cultures, but these studies have been based on restriction fragment length polymorphism markers that do not provide information on candidate genes. A recent transcript‐derived marker barley map based on expressed sequence tags was used to locate QTL for barley green plant regeneration and identify candidate genes. Quantitative trait loci analysis identified four significant regions, on chromosomes 2H, 3H, 6H, and 7H, in places where QTL were previously identified. An additional four regions were suggestive for green and/or albino plant regeneration on chromosomes 1H, 3H, 4H, and 5H. Examination of transcript‐derived markers at the QTL peaks showed that many genes identified as important for regeneration in other species were located in these QTL peaks, including a gene for ferredoxin‐nitrate reductase and genes involved in hormone response and synthesis, cell division and the cell cycle, chloroplast development, and transcription factors. Identifying these genes allows manipulation to better understand the processes involved in regeneration from barley tissue cultures.
Identification of Flanking Markers for the Stem Rust Resistance Gene Sr6 in Wheat
Authors: Tsilo Toi J. , Jin Yue , Anderson James A.
Published: August 2010

The wheat (Triticum aestivum L. and T. turgidum L.) stem rust resistance gene Sr6 confers a high level of resistance against a wide range of races of Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. and E. Henn. in North America. In this study, we report the identification of flanking markers for Sr6. We used a population of 139 recombinant inbred lines from the cross MN99394 × MN98550. A partial linkage map of chromosome 2D comprised Xgwm484, Xcfd77, Xcfd43, Xwmc453, Sr6, XwPt_4381, XwPt_0330, Xgpw94049, and Xgwm102. Four markers mapped distal to Sr6, while the other four were proximal within distances of 4.8 and 6.5 cM, respectively. Marker‐assisted selection and pyramiding of Sr6 with other stem rust resistance genes could benefit from the availability of Sr6‐flanking markers.
Irrigation and Time of Harvest Effects on Evaluation of Selected Soybean Accessions Against Phomopsis longicolla
Authors: Mengistu A. , Smith J. R. , Bellaloui N. , Paris R. L. , Wrather J. A.
Published: August 2010

Phomopsis seed decay (PSD) of soybean (Glycine max L. Merr) is primarily caused by Phomopsis longicolla. Currently, percent seed infection is used as a method for evaluating resistance to PSD. However, researchers need a common system for classifying soybean genotypes for their reaction to P.longicolla that is consistent across environments. The purpose of this research was: (i) to evaluate the reaction of a select set of soybean accessions to P. longicolla, and (ii) determine the effects of irrigation and two harvest regimes (normal and delayed) on seed infection. We propose a classification system for comparing reactions to P. longicolla among accessions based on a Phomopsis seed infection index (PSII), derived by dividing the percent seed infection of each accession by percent seed infection values of susceptible standards selected within early and late maturity groups. Percent seed infection by P. longicolla infection was greater when accessions were irrigated during the growing season and harvested at normal maturity. Some lines such as MO/PSD‐0259 were rated as resistant to P. longicolla (7% seed infection) when not irrigated and harvested at maturity, but were rated as susceptible (39% seed infection) with irrigation and delayed harvest. The resistance ratings to P. longicolla using percent seed infection and PSII varied among accessions. SS93–6012, for example, had similar ratings for both (9% seed infection and 16% PSII). PI 416942 exhibited some resistance to P. longicolla based on percent seed infection (8%), but no resistance based on PSII (32%). Accessions PI 594478, Delmar, SS93–6012, SS93–6181, PI 594603A, and PI 594712 were classified by PSII as moderately resistant under irrigation and with delayed harvest. These results indicate that simple comparisons of percent seed infection among accessions without irrigation, without delayed harvest, and without a standard control of a similar maturity group might result in false conclusions about resistance to P. longicolla.
Selection for Forage Yield and Composition on the Wisconsin Quality Synthetic Maize Population
Authors: Gustafson T. J. , Coors J. G. , de Leon N.
Published: August 2010

Wisconsin Quality Synthetic (WQS) is a maize population that has undergone four cycles of S2–topcross selection for increased silage yield and feed quality. This study evaluated forage yield and quality for each cycle of WQS per se as well as testcrosses to two Stiff Stalk‐type testers. Linear improvement was seen in whole‐plant yield, stover yield, and whole‐plant quality both in the population per se and in testcrosses. Stover quality has not improved through selection. Starch content has increased while crude protein has decreased. Milk yields on a Mg dry matter and hectare basis have increased with selection. Changes in silage dry matter yield have been greater on a percent basis than changes in silage quality, suggesting that the current selection protocol of selecting S2–topcrosses first for yield then for quality may be more efficient at improving yield than quality. Selection directly focused on stover quality may be necessary if more rapid improvement in stover composition is desired.
Forage Yield, Growth Rate, and Nitrogen Uptake of Faba Bean Intercrops with Wheat, Barley, and Rye in Three Seeding Ratios
Authors: Lithourgidis A. S. , Dordas C. A.
Published: August 2010

Annual cool‐season grain legumes like faba bean (Vicia faba L.) grown in mixtures with winter cereals such as wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), or rye (Secale cereale L.) may offer advantages over cereal‐alone crops grown for forage production. A 2‐yr field study was conducted to evaluate the effects of intercropping faba bean with each of the above cereals in three seeding ratios (i.e., 75:25, 50:50, and 75:25) on growth rate, plant height, chlorophyll content, forage yield, and N uptake. Growth rate of faba bean and cereals was lower in the mixtures than in the monocultures, especially in the faba bean–barley mixtures because of the strong competitive ability of barley. Chlorophyll content was lower in faba bean compared with the cereals, and there was no difference among seeding ratios. Plant height of faba bean was higher in the intercrops compared with its monocrop at 3 wk after tillering (WAT), whereas at 6 WAT, the trend was different since faba bean plants in the monocrop were higher than in the intercrops. Rye monocrop and rye–faba bean intercrops provided the greatest forage yield. Although the three intercrops of faba bean with rye had lower crude protein (CP) content than the faba bean monocrop, they provided the highest CP yields per hectare because of their higher forage yield than the faba bean monocrop.
Bahiagrass Tiller Dynamics in Response to Defoliation Management
Authors: Interrante S. M. , Sollenberger L. E. , Blount A. R. S. , White‐Leech R. , Liu K.
Published: August 2010

New bahiagrass (Paspalum notatum Flügge) genotype PCA Cycle 4 is more productive than existing bahiagrass cultivars during the cool season, but it may not persist as well when defoliated frequently or to short stubble. Characterizing tiller dynamics forms a basis for understanding mechanisms of grass yield and persistence responses to defoliation. A 2‐yr field experiment studied the effects of two stubble heights (4 and 8 cm) and two harvest frequencies (7 and 21 d) on tiller dynamics of diploid (PCA Cycle 4, ‘Pensacola’, and ‘Tifton 9’) and tetraploid (‘Argentine’ and Tifton 7) bahiagrass. Tiller number of highly persistent Argentine and Pensacola was unaffected by defoliation treatment and generally greatest among cultivars. Tiller number of Tifton 9 and PCA Cycle 4 varied by up to 970 and 730 tillers m−2, respectively, among defoliation treatments and was greatest with frequent harvests at short stubble. PCA Cycle 4 tiller mass was relatively low. Net tiller appearance rate was positive in spring and early summer, and was nearly zero or negative throughout the remainder of the growing season. This study showed that Tifton 9 and PCA Cycle 4 responded to frequent, close defoliation by increasing tiller number, but tiller mass was the least or not different from the least among entries tested. Very small tillers may indicate a weakening stand under frequent, close defoliation, and management practices such as rotational stocking may be necessary for PCA Cycle 4 to persist.
Role of Summer Dormant Perennial Grasses as Intercrops in Rainfed Mediterranean Vineyards
Authors: Volaire F. , Lelièvre F.
Published: August 2010

Grass swards are increasingly used in vineyards to improve ecosystem function, reduce vine vigor, and enhance grape (Vitis vinifera L.) quality. In Mediterranean rainfed vineyards, the use of intercropping has been constrained because of excessive competition for water with the vine over summer. We aimed to test cultivars of Mediterranean forage grasses with a range of summer dormancy, which confers low competitiveness for water and high persistence. A 4‐yr experiment compared a bare soil control and three perennial grass cultivars as interrows in a vineyard: orchardgrass (Dactylis glomerata L.) ‘Kasbah’ and ‘Bacchus’ and tall fescue [Lolium arundinaceum (Schreb.) Darbysh] ‘Centurion’. In the spring of 2006, Centurion had extracted water to the 150‐cm depth, whereas neither orchardgrasses had extracted water beyond the 120‐cm depth. In the summers of 2006 and 2007, Centurion used 30 to 50 mm more of the soil water reserve in the 0‐ to 150‐cm soil layer than the bare soil control. Vine predawn leaf water potential, vine leaf area index (LAI), and biomass of pruned shoot and of vine fruit were also significantly affected by intercrops. The best intercrop was the least competitive cultivar, Kasbah, because of its low biomass production and complete summer dormancy. Bacchus is not summer dormant and was the least persistent. Centurion was the most competitive because of its deep root system and incomplete summer dormancy. The results raise the needs for breeding a larger range of adapted cultivars for intercropping rainfed Mediterranean vineyards.
Differential Growth and Carbohydrate Usage in Switchgrass Ecotypes under Suboptimal Temperatures
Authors: Gesch R. W. , Johnson J. M‐F.
Published: August 2010

Switchgrass (Panicum virgatumL.) is widely adapted throughout North America, but its productivity tends to decline with increasing latitude. Little is known about its genetic potential to photosynthetically acclimate to suboptimal growth temperature, although such potential could be useful to enhance productivity. To examine this, a growth chamber study was conducted with two lowland (Alamo and Kanlow) and two upland (Cave in Rock and Sunburst) ecotypes grown under day/night air temperatures of 32/24°C and later switched to 22/14°C. Photosynthesis, growth, and carbohydrates were analyzed before and after temperature switching. Photosynthesis was greater in lowland than upland cultivars at 32°C air temperature. After switching to 22/14°C and allowing plants to adjust, photosynthesis declined with little difference among cultivars. Moreover, photosynthetic capacity among cultivars slightly decreased or remained similar compared to before the temperature switch. However, after switching to 22/14°C, Alamo gained the most dry matter (3.9 g plant−1), which was 69, 82, and 152% greater than that of Sunburst, Kanlow, and Cave in Rock, respectively. Total nonstructural carbohydrates increased at 22/14°C, but Alamo showed the least change and no difference in leaf sucrose/starch ratio following the switch. Maintenance of carbon metabolism favoring growth, but not photosynthetic acclimation, may be a key to enhancing switchgrass productivity under suboptimal growth temperatures.
Effect of soil temperature and moisture on the pathogenicity of two species of entomopathogenic nematodes (Rhabditida: Steinernematidae)
Authors: Radová Štěpánka , Trnková Zuzana
Published: August 2010

Effect of soil temperature and moisture on the pathogenicity of two species of entomopathogenic nematodes (Rhabditida: Steinernematidae)

This study investigated the impact of soil temperature and soil moisture on the virulence of the entomopathogenic nematodes Steinernema carpocapsae and S. feltiae. The effects of temperatures of 10, 15 and 25 °C and humidity of 6% and 12.5% were tested against the larvae of Tenebrio molitor. The nematodes were tested in two concentrations of 50 nematodes and 500 nematodes per box. S. carpocapsae was generally significantly more efficient at the highest temperature (25 °C) than S. feltiae, especially at the lower concentration of 50 nematodes per box. S. feltiae recorded higher insect mortality at lower temperatures (15 °C and 10 °C). The virulence of both tested nematode species was low (0-26%) at 10 °C after 7 days, but in the case of S. feltiae increased to 66% after 14 days. The efficacy when tested with 6% moisture at 15 °C was low (4% for both nematode species) compared with 12.5% moisture, where after seven days it reached 54% for S. carpocapsae and 70% for S. feltiae, although generally, S. feltiae was more efficient under dry conditions than S. carpocapsae. Insect mortality inreased significantly after remoistening of the soil, especially with S. feltiae (500 nematodes per box) where mortality reached 46% two weeks after remoistening.
Content of selected biologically active compounds in tea infusions of widely used European medicinal plants
Authors: Dadáková Eva , Vrchotová Naděžda , Tříska Jan
Published: August 2010

Content of selected biologically active compounds in tea infusions of widely used European medicinal plants

Herbal tea infusions are a very important source of flavonoids and other biologically active compounds in human medicine and nutrition. Melissa officinalis, Agrimonia eupatoria, Sambucus nigra, Achillea millefolium, Filipendula ulmaria, Betula pendula and Glechoma hederacea were selected as common European medicinal herbs and sources for tea infusion preparations. Quercetin, rutin, catechin, chlorogenic acid, and squalene were determined in the prepared infusions. Free quercetin was not found in any of the infusions, but tea infusions did contain rutin and other quercetin glycosides, the content of which was, after acid hydrolysis, determined as quercetin. The highest levels of total quercetin were found in infusions from Filipendula ulmaria and Sambucus nigra (120 and 108 mg L-1, respectively) corresponding to the content of rutin found also in these two infusions (25.2 and 194 mg L-1, respectively). The Sambucus nigra infusion contained the largest content of chlorogenic acid (166 mg L-1), and infusions from Melissa officinalis, Agrimonia eupatoria, Betula pendula and Glechoma hederacea contained only small amounts of squalene.
Can pre-colonisation of the soil substrate increase the efficacy of entomopathogenic nematodes (Rhabditida: Steinernematidae)?
Authors: Radová Štěpánka
Published: August 2010

Can pre-colonisation of the soil substrate increase the efficacy of entomopathogenic nematodes (Rhabditida: Steinernematidae)?

The effects of soil pre-colonisation with entomopathogenic nematodes Steinernema feltiae, S. carpocapsae and S. arenarium on the mortality of Tenebrio molitor larvae were tested under laboratory conditions. The soil was inhabited with the nematodes for 7 days prior to the addition of the larvae. Nematode concentrations of 50 and 500 infective juveniles per box were used. S. carpocapsae reacted to pre-colonisation negatively and the efficacy decreased at the concentrations tested. S. arenarium showed generally low efficacy against Tenebrio molitor larvae and pre-colonisation showed only a slight positive effect on the efficacy of this species. S. feltiae increased its efficacy at the concentration of 500 infective juveniles per box compared with other tested nematodes.
Analysis of longterm trends in the performance of dairy cows on low-input mountain farms
Authors: Frelich Jan , Šlachta Martin , Kobes Milan
Published: August 2010

Analysis of longterm trends in the performance of dairy cows on low-input mountain farms

The productive and reproductive performance of dairy cows was examined on thirty-four low-input farms in the Šumava Mts. between 2000 and 2007. Milk production increased by an average of 986 kg and 948 kg per lactation by Holstein and by Czech Fleckvieh cows, respectively (P<0.001), while the mean number of lactations decreased from 2.7 to 2.5 in Holstein and from 3.4. to 3.0 in Czech Fleckvieh cows (P<0.001) in the same period. The mean number of lactations decreased also in the culled cows - from 3.2 to 2.9 by Holstein and from 4.3 to 3.5 by Czech Fleckvieh cows (P<0.001). A higher cow milk yield was accompanied by a deterioration in reproductive performance. Between the periods 2000-2003 and 2004-2007 the number of days open lengthened by an average of 6 and 4 days (P<0.01) and the calving period by an average of 11 and 6 days (P<0.001) in Holstein and Czech Fleckvieh cows respectively. The results indicated an increased replacement of cows in the herds examined as a coincidental feature of the steadily rising milk performance. This may have a negative impact on the rentability of low-input mountain dairy farming in the region.
Reasons for the culling of dairy cows on low-input mountain farms
Authors: Frelich Jan , Šlachta Martin , Kobes Milan
Published: August 2010

Reasons for the culling of dairy cows on low-input mountain farms

Reasons for the culling of dairy cows were scrutinized on thirty-four low-input farms in the Šumava mountains in the Czech Republic. An increase in the frequency of the most common culling category - category 58 (other health reasons) - was identified in both the Holstein and Czech Fleckvieh breeds between 2000 and 2007: from 35% to 59% in the Holstein cows and from 19% to 41% in the Czech Fleckvieh cows (X2 test; P<0.001). This brought the Czech Fleckvieh cows to the same level of frequency as in the Czech Republic population, while the frequency among Holstein cows was on average 11% higher than in the Czech Republic population. The frequency of category 58 was higher in the Holstein than in the Czech Fleckvieh cows, but category 52 (low milk production) was more frequent in the Czech Fleckvieh than in the Holstein cows (P<0.001). There is a link between category 58 ‘other health reasons’ and an increase in the milk productivity of the cows; this results eventually in a higher incidence of metabolic disorders and is discussed in this paper.
Retrotransposons and ethyl methanesulfonate-induced diversity in hexaploid wheat and Triticale
Authors: Bonchev Georgi , Georgiev Sevdalin , Pearce Stephen
Published: August 2010

The bulk of large plant genomes consists of retrotransposons. Retrotransposons are able to integrate into a multitude of loci in the genome, and can thereby generate insertional polymorphism between individuals, as well as mutations and new characteristics. Retrotransposons are largely quiescent during development, but become more active in response to biotic and abiotic stresses, which cause them to produce larger pools of transcripts. The present study assesses the structural dynamics and putative transcriptional activation of BARE-1 and WIS 2-1A retrotransposons in ethyl methanesulfonate (EMS)-induced hexaploid wheat and Triticale sphaerococcum mutants, via an RT-PCR approach that utilized the retrotransposon based markers SSAP, IRAP and REMAP. Our results demonstrate a polymorphic pattern distribution of BARE-1/WIS 2-1A members, and identify new insertions. The WIS 2-1A retrotransposon members have a modulated transcriptional profile, which strongly suggests that EMS treatment encourages their activation Retrotransposon-based methods are efficient for fingerprinting and genetic polymorphism studies of sphaerococcum mutant forms, and can illuminate the genome dynamics affecting the genes responsible for the sphaerococcum phenotype.
The anatomical and micromorphological characteristics of Salvia vermifolia (Section Aethiopis Bentham, Lamiaceae) from Central Anatolia, Turkey
Authors: Bagherpour Safi , Kahraman Ahmet , Doğan Musa , Celep Ferhat , Başer Birol , Pehlivan Sevil
Published: August 2010

The gross anatomical features, namely stem, blade and petiole and the micromorphological features, trichome, pollen and nutlet of Salvia vermifolia Hedge & Hub.-Mor. (Sect. Aethiopis Bentham, Lamiaceae) were examined using light microscopy (LM) and scanning electron microscopy (SEM). S. vermifolia is a perennial endemic herb growing on igneous and serpentine slopes in Sivas province, Central Anatolia, Turkey. The results obtained from anatomical studies show that the stem is made up of 4–8-layers of collenchyma cells and 1-3-layers chlorenchyma cells. The blade is amphistomatic, bifacial, with 2-3-layered palisade cells on the adaxial. The petiole has three large central bundles and six small subsidiary bundles. Peltate glandular, capitate glandular and non-glandular trichomes are present in S. vermifolia. The peltate glandular trichomes are present in abundance on the calyx and corolla, and capitate glandular trichomes are predominant on the calyx, inflorescence axis, pedicel and stem. The acicular non-glandular trichomes are mainly situated on the calyx, corolla, inflorescence axis and pedicels whereas the floccose non-glandular trichomes are common on both sides of the leaf, inflorescence axis and petiole. The pollen grains are hexacolpate to octacolpate, medium to large (P, polar axis=45.29–62.49 μm; E, equatorial axis=45.32-62.38 μm), oblate-spheroidal to prolate-spheroidal (P/E=0.91–1.02) and their exine ornamentation is bireticulate. The nutlets are 2.70–2.90 mm long and 1.90–2.13 mm wide, brown, ovoid-oblong in their outline, rounded-trigonous in transverse section, and their surface is glabrous and colliculate.
Ceruloplasmin and oxidized LDL colocalize in atherosclerotic lesions of hamster
Authors: Stancu Camelia , Constantinescu Elena , Sima Anca
Published: August 2010

Epidemiological studies show that the risk for cardiovascular diseases increases with increasing levels of free-copper in plasma. It is known that intact ceruloplasmin (CP), the major protein transporter of copper in human plasma, oxidizes low density lipoproteins (LDL) in vitro. Our aim was to study the interaction between LDL and CP in vitro and in vivo, in an animal model of diet-induced atherosclerosis. In order to visualize the pathway of LDL into the arterial wall, human native LDL was labeled with fluorescent DiI and injected into male, Golden Syrian hyperlipemic hamsters. In vitro results demonstrated that slightly degraded CP has a significant oxidation potential against LDL at neutral pH. In vivo, after 24 hours circulation, LDL-DiI was taken up by the enlarged intima and fatty streaks of the arterial wall. Immunohistochemical localization of oxidized LDL and CP revealed their presence in the same areas of the arteries that take up LDL-DiI. Co-localization of LDL and CP in the enlarged intima of pro-atherosclerotic areas might explain the possible copper-induced oxidation process that might occur after native LDL is taken-up from the blood, transcytosed through the endothelium and accumulated in focalized deposits.
Three-dimensional Finite Element Solution of the Flow in Single and Twin-Screw Extruders
Authors: Ilinca F. , Hétu J.-F.
Published: August 2010

This work is aimed at the numerical modeling of the flow inside single and twin-screw extruders. Numerical solutions are obtained using a recently developed immersed boundary finite element method capable of solving the flow in the presence of complex non-stationary solid boundaries. The method is first validated against the solution obtained on a body-conforming grid for a single screw extruder and then applied to a twin-screw mixer. The time dependent single screw problem can also be solved in a rotating reference frame for which a steady state solution can be obtained. This allows the evaluation of time integration errors of the moving immersed interface algorithm. For instance the flow is considered isothermal and the material behaves as a Generalized Newtonian fluid. Because the viscosity depends on the shear rate, solutions will be shown for various rotation velocities of the screw and compared with solutions obtained on body-conforming grids. The method is shown to give very accurate results and can be used for a more in-depth investigation of the material behavior in extruders.
RheoDSC Analysis of Hardening of Semi-Crystalline Polymers during Quiescent Isothermal Crystallization
Authors: Janssens V. , Block C. , Van Assche G. , Van Mele B. , Van Puyvelde P.
Published: August 2010

The crystallization of semi-crystalline polymers is often analyzed by rheometry and calorimetry. By rheometry the viscosity evolution during crystallization can be followed, whereas from a calorimetric measurement, the evolution of the degree of crystallinity can be calculated. The time evolution of these material properties is valuable input for polymer processing simulation software and in order to combine the data in a reliable manner, hardening curves are used as a characterization tool. Such a hardening curve correlates the relative increase of the viscosity resulting from crystallization, to the advancing degree of crystallinity. In this study, these are extracted from simultaneous measurements on one sample using a RheoDSC device. The RheoDSC technique allows for the direct combination of the rheological and calorimetric signal without the need of combining separate stand-alone measurement results. In this study, isothermal crystallization experiments are used to discuss the benefits of this approach. This will lead to the recommendation that measuring the hardening effect in steady shear measurements at very low shear rates in a direct combined RheoDSC setup is the most reliable method to compile unambiguously a material specific hardening curve for semi-crystalline polymers.
Correlating Bid Price with the Number of Bidders and Final Construction Cost of Public Street Projects
Authors: Shrestha Pramen Prasad , Pradhananga Nipesh
Published: August 2010

The vast majority of highway and street projects in the United States are procured by state or local governments through a competitive bidding process. In a competitively bid public project, awarding the contract to the lowest bidder is a predominant practice. A few studies measured the effect of awarding the contract to the lowest bidder on construction cost growth. This paper analyzes a sample of 435 bids on 113 public street projects in Clark County, Nevada, to determine a correlation between a lowest bid price and construction cost growth. The sample included projects completed between 1991 and 2008 and more than $554 million in construction value. The study also determined a correlation between the number of bidders and the deviation of the bid cost from the engineers’ estimate. The study showed no correlation between the lowest bid price and the construction cost growth. It showed that public owners would have received the lowest construction bid price if more bidders had been involved in the bidding process. The study found a strong correlation between the lowest bid price and the final construction cost. Therefore, a regression model was developed to predict the final construction cost of a street project by using the lowest bid price. A validation of the model showed that on average the predicted cost of a project was within 3.51% of the actual construction cost. Other findings included recommendations for future study.
Quantifying Time and User Cost Savings for Rapid Bridge Construction Technique
Authors: Abudayyeh Osama , Cai Hubo , Mellema Brock , Yehia Sherif
Published: August 2010

The rapid bridge construction (RBC) technique is the most recent application of precast concrete technology. While time saving is the main advantage of this emerging technology, a major obstacle to adopting RBC is the common perception that it has a high initial cost. This paper presents a methodology for assessing the savings in time and user costs associated with adopting RBC techniques. A case study is also presented to demonstrate how the assessment methodology can be implemented. A comparison study was carried out to assess the performance of RBC through use of an actual bridge construction project. The results of this study indicate that RBC technology may offer a more efficient and economical alternative to the conventional method.