bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maternal Effects on Fatty Acid Composition of Soybean Seed Oil
Authors: Gilsinger J. J. , Burton J. W. , Carter T. E. 
Published: August 2010

ABSTRACTThe 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

ABSTRACTInbred 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

ABSTRACTManagement 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

ABSTRACTPlant 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

ABSTRACTAn 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

ABSTRACTForage 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

ABSTRACTMoisture 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

ABSTRACTGreen 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

ABSTRACTThe 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

ABSTRACTPhomopsis 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

ABSTRACTWisconsin 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

ABSTRACTAnnual 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

ABSTRACTNew 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

ABSTRACTGrass 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

ABSTRACTSwitchgrass (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.