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St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] is a popular warm‐season turfgrass in the southern United States. Gray leaf spot (GLS), caused by the fungal pathogen Pyricularia oryzae Cavara, is one of the major diseases in St. Augustinegrass. Although previous studies have reported polyploid lines with resistance to GLS, no comprehensive evaluations of sources of resistance have been performed in the genus. Such evaluations will enable breeders to identify resistant parents for cultivar development. In this study, 58 genotypes of St. Augustinegrass and two genotypes of pembagrass [Stenotaphrum dimidiatum (L.) Brongn.] were screened for resistance to three different P. oryzae sources of inoculum under controlled environmental conditions. The parameters evaluated were incubation period, number of leaves with lesions, mean lesion length, area under the disease progress curve (AUDPC), and area under the lesion expansion curve (AULEC). Significant differences among genotypes were identified. Polyploid genotypes PI 365031, PI 290888, PI 300129, PI 300130, and cultivar 'FX‐10' and diploid genotype PI 410353 consistently showed high levels of resistance across trials, inoculum sources, and parameters. The identification of resistance genes in diploid genotypes is of great importance for future St. Augustinegrass breeding efforts, as this germplasm pool can be more readily exploited because of the lack of reproductive barriers with most commercial cultivars and plant introductions. [ABSTRACT FROM AUTHOR]

Zoysiagrasses (Zoysia spp.) are relatively low‐input and warm‐season turfgrasses which have grown in popularity in the United States since their introduction in the 1890s. Over 30 improved zoysiagrass cultivars were released in the past three decades, but many lack freezing tolerance and their use is limited to warm‐humid climates. Understanding the genetic controls of winter hardiness and freezing tolerance in zoysiagrass could considerably benefit the breeding efforts to increase tolerance to freezing stress. In the present study, controlled environment acclimation and freezing tests were used to evaluate a Meyer × Victoria zoysiagrass mapping population for post‐freezing surviving green tissue (SGT) and regrowth (RG). Quantitative trait loci (QTL) mapping analysis identified nine QTL associated with SGT, eight QTL linked to RG, and 22 QTL common in both traits, accounting for between 6.4 and 12.2% of the phenotypic variation. Eleven regions of interest overlapped with putative winter injury QTL identified in a previous field study. Upon sequence analysis, homologs of several abiotic response genes were found underlying these overlapping QTL regions. The homologs of these gene encode transcription factors, cell wall modification‐related proteins, and defense signal transduction‐related proteins. After further validation, these QTL and their associated markers have potential to be used in future breeding efforts for the development of a broader pool of zoysiagrass cultivars capable of surviving in cold climates. [ABSTRACT FROM AUTHOR]

Zoysiagrasses (Zoysia spp.) are warm‐season turfgrasses primarily grown in the southern and transition zones of the United States. An understanding of the physiological and proteomic changes that zoysiagrasses undergo during cold acclimation may shed light on phenotypic traits and proteins useful in selection of freeze‐tolerant genotypes. We investigated the relationship between cold acclimation, protein expression, and freeze tolerance in cold acclimated (CA) and nonacclimated (NA) plants of Zoysia japonica Steud. cultivars Meyer (freeze‐tolerant) and Victoria (freeze‐susceptible). Meristematic tissues from the grass crowns were harvested for proteomic analysis. Freeze testing indicated that cold acclimation accounted for a 1.9‐fold increase in plant survival than nonacclimation treatment. Overall, proteomic analysis identified 62 protein spots differentially accumulated in abundance under cold acclimation. Nine and 22 unique protein spots were identified for Meyer and Victoria, respectively, with increased abundance or decreased abundance. In addition, 23 shared protein spots were found among the two cultivars in response to cold acclimation. Function classification revealed that these proteins were involved primarily in transcription, signal transduction and stress defense, carbohydrate and energy metabolism, and protein and amino acid metabolism. Several proteins of interest for their association with cold acclimation were identified. Further investigation of these proteins and their functional categories may contribute to increase our understanding of the differences in freezing tolerance among zoysiagrass germplasm. [ABSTRACT FROM AUTHOR]

Water table data collected for hydric soil and wetland identification studies require supporting analysis of rainfall normality. Water table measurements made after periods when precipitation is within a normal range are believed to represent long-term trends, whereas data collected following periods of abnormally high precipitation represent rare events, potentially resulting in erroneous hydric soil determinations. The USDA-NRCS currently uses two different methods to assess normal precipitation ranges; both have been used to assess hydric soils. This study compared methodologies that identify normal precipitation periods by using: (i) the range defined by the 30th and 70th percentiles observed within a 30-yr period [i.e., the Climate Analysis for Wetlands Tables (WETS) method] and (ii) long-term monthly mean precipitation ± one SD (i.e., the U.S. Soil Taxonomy method). Comparisons were made for 30 geographically diverse locations and soil moisture regimes. The results demonstrated that the U.S. Soil Taxonomy method yielded normal precipitation ranges approximately twice as large as those from the WETS method. As a result, the U.S. Soil Taxonomy method precluded the occurrence of drier than normal conditions in many instances and displayed increased sensitivity to infrequent high rainfall events. Three case studies evaluated the implications of method selection on hydric soil identification, demonstrating that the U.S. Soil Taxonomy method identified normal conditions more frequently than the WETS method. As a result, the adoption of the WETS method, which accounts for the non-normal distribution of precipitation data, as the sole method to determine normal precipitation periods for hydric soil assessment is recommended. [ABSTRACT FROM AUTHOR]

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) is one of the most widely used herbicides worldwide, and groundwater contamination is of concern, especially in heavily used regions and in edaphic conditions prone to leaching. Soil sorption plays an essential role in atrazine environmental fate, yet consistent atrazine risk prediction remains limited. A quantitative meta-analysis was conducted to characterize the effect of soil properties on atrazine sorption, using 378 previous observations in 48 publications from 1985 to 2015 globally, which included data on soil properties and sorption parameters. A supplemental regional study was conducted to test the derived meta-analysis models. The meta-analysis indicated that percentage organic C (OC) was the most important parameter for estimating atrazine sorption, followed by percentage silt, soil pH, and percentage clay. Meta-analysis and supplemental study models were developed for Freundlich sorption coefficients (K1) and sorption distribution coefficients (Kd) as a function of OC. The global meta-analysis models generated positive linear trends for OC with Kf and Kd (R² = 0.197 and 0.205, respectively). Organic C was highly correlated with Kf and Kd in supplemental experimental study models (R² = 0.93 and 0.92, respectively), indicating accurate prediction of sorption within the evaluated region. Continental models were investigated, which improved the goodness of fit. Models developed via metaanalysis may be used to predict atrazine sorption over wide ranges of data, whereas more accurate and refined prediction can be achieved by specific regional models through experimental studies. However, such models could be improved if standardized agroclimatic conditions, soil classification, and other key variables were more widely reported. [ABSTRACT FROM AUTHOR]

Objectives: Certified Safe Farm (CSF) is a multimodal intervention composed of four components: safety, health, education, and economic incentive. North Carolina has conducted the largest implementation of CSF outside of the Midwestern United States where it was developed. This paper describes the Efficacy dimension of the Reach Effectiveness Adoption Implementation Maintenance (RE-AIM) framework for the implementation of CSF in North Carolina during 2009-2012 on 113 farms in a three-county, highly productive and diverse agricultural area. Methods: Using descriptive statistics, analysis of variance, correlational analyses, and logistic regression, quantitative data were examined from on-farm safety reviews, as well as primary operators’ use of cost-share funds as an economic incentive (34% participation) to make identified safety and health improvements on the farm. Results: Overall farm safety review scores were generally high (96% passing rate). Category scores revealed hazards in seven key categories: Chemical Storage; Tractors; Machine Shop, Repair Area; Gravity Flow, Auger, and Forage Wagons; Portable Augers; Dairy and Beef Structures; and Swine and Poultry Structures. The cost-share economic incentive component was utilized in addressing hazards in five of these categories, as well as in nine others. The average per farm cost-share reimbursement was $3,276, with a median of $1,615. In total, an investment of $255,307 (farmer investment plus incentive) was made in safety and health improvements on farms (n = 38). Correlation and logistic regression analyses revealed no significant relationships among scores, cost-share investments, and selected farm demographics. Conclusion: Findings suggest the 50% cost-share for safety and health improvements is a promising economic incentive model for CSF implementation. [ABSTRACT FROM AUTHOR]

We investigated impacts of simultaneous production of biomass for biofuel and quality timber on soil nitrogen (N) cycling in a poorly drained forest soil of eastern North Carolina, U.S.A. Treatments included traditional loblolly pine (PINE) and pine-switchgrass intercropping (PSWITCH). Treatments were replicated three times on 0.8 ha plots drained by parallel open ditches which were 1.2 m deep and spaced 100 m apart. Net N mineralization ( N m ) and nitrification ( N n ) rates were measured in the field using sequential in-situ technique over two years with multiple measurements in each year and laboratory by incubating soil samples for one-, two-, eight-, and thirteen weeks. Soil incubation in-situ or sample collection for laboratory incubation was conducted at nine sampling points within a 30 × 40 m subplot at each plot center and 20 cm from the soil surface. Soil samples were composited by location including near tree (NT), between two trees on the same bed (BT), and in the middle of four trees on two adjacent beds (M4T). Composite samples from NT and BT were categorized as tree-bed (BED), while those from M4T were grouped as interbed (INT). Field results showed that total soil N availability and its temporal variations over two years were not significantly affected by PSWITCH. However, it significantly reduced N n rates, particularly in the INT. The plot-level mean N m rates in PINE were 0.21 and 0.26 mg N·kg soil −1  d −1 , while in PSWITCH they were 0.10 and 0.21 mg N kg soil −1  d −1 in 2011 and 2012, respectively. The plot-level mean N n rates in PINE were 0.09 and 0.10 mg N kg soil −1  d −1 in 2011 and 2012, respectively, while in PSWITCH they remained at 0.03 mg N kg soil −1  d −1 across these two years. At the INT, mean N n rates in PINE were 0.11 and 0.12 mg N kg soil −1  d −1 in 2011 and 2012, respectively, while in PSWITCH, N n rate remained at 0.02 mg N kg soil −1  d −1 over two years. Laboratory results indicated that change in litter quality inputs (changing from mixed species to switchgrass) in the INT did not significantly affect N m rates. Results of this study contributed to a better understanding of the changes in soil N cycling due to loblolly pine-switchgrass interactions, which is important in sustainable nutrient management of this new land use. Further, the results suggested that growing switchgrass as intercrop to managed loblolly pine has positive water quality implication since ammonium N is less mobile in soil than nitrate N. [ABSTRACT FROM AUTHOR]

Nicotine is naturally synthesized in tobacco roots and accumulates in leaves as a defense compound against herbivory attack. Nicotine biosynthesis pathway has been extensively studied with major genes and enzymes being isolated and functionally characterized. However, the molecular regulation of nicotine synthesis has not been fully understood. The phytohormone jasmonic acid (JA) mediates many aspects of plant defense responses including nicotine biosynthesis. In this study, five key genes (AtLOX2, AtAOS, AtAOC2, AtOPR3, AtJAR1) involved in JA biosynthesis from Arabidopsis were individually overexpressed, and a JA‐Ile hydrolysis‐related gene, NtJIH1, was suppressed by RNAi approach, to understand their effects on nicotine accumulation in tobacco. Interestingly, while transgene expression was high, levels of JA‐Ile (the biologically active form of JA) were often significantly reduced. Meanwhile, nicotine content in these transgenic plants did not increase. The research revealed a tightly controlled JA signaling pathway and a complicated regulatory network for nicotine biosynthesis by JA signaling. [ABSTRACT FROM AUTHOR]

Zoysia japonica Steud. (2 n = 4 × = 40) is a C turfgrass well-adapted for the warm-humid and transitional climatic zones of the USA. Its use is limited to warmer climates because of a relative lack of winter hardiness compared to C grasses. Molecular markers associated with this trait would be useful for effective selection of winter hardy germplasm before field testing. A pseudo-F mapping population of 175 individuals was developed from crosses between Z. japonica cultivars 'Meyer' (freeze-tolerant) and 'Victoria' (freeze-susceptible) and used to generate a high-density genetic map of 104 SSR markers and 2359 sequencing-derived SNP markers. The map covers 324 Mbp and 2520 cM as well as the 20 chromosomes for the zoysiagrass haploid genome. Phenotypic data on winter injury, establishment, and turf quality collected in North Carolina and Indiana in 2014-2016 were used in conjunction with this map to identify quantitative trait loci (QTL) associated with winter hardiness. Fifty-six QTL associated with winter injury, establishment, and turf quality were identified over six environments. Twelve of those were identified in two or more environments. Furthermore, seven regions of interest were identified on chromosomes 8, 11, and 13 where co-location of QTL for three or more traits occurred. Within these regions, analysis with NCBI basic local alignment search tool (BLAST) identified proteins related to cold and other abiotic stresses tolerance. These QTL and associated markers could be valuable in implementing marker-assisted selection for winter hardiness in zoysiagrass breeding programs. [ABSTRACT FROM AUTHOR]

The adaptation of St. Augustinegrass (Stenotaphrum secundatum [Walt.] Kuntze) in the transitional climatic zone of the United States is limited due to a lack of sufficient freeze tolerance. Lab-based freeze testing provides plant breeders with a reliable method for evaluating freeze tolerance. However, in developing protocols for freeze testing it is important to account for the underlying mechanisms that affect freeze tolerance. The objective of this research was to evaluate the effects of cold acclimation and deacclimation on nine St. Augustinegrass genotypes ranging in their levels of freeze tolerance. Results indicated that accounting for all levels of acclimation provided excellent genotype separation across freezing temperatures(- 3 and - 4°C) and supports the hypothesis that the inclusion of acclimation response offers the best overall assessment of freeze tolerance. Genotypes with the highest known field winter survival had also the highest improved freeze tolerance upon cold-acclimation. Other genotypes did not respond to cold-acclimation which resulted in poor survival and recovery rates. Conversely, a significant loss of freeze tolerance was identified when plants were subjected to deacclimation events suggesting that St. Augustinegrass can be negatively affected by rapid temperature changes in the transitional climatic zone leading to increased sensitivity to winterkill. Overall, this study provides preliminary information regarding the complex relationships within and between mechanisms affecting freeze tolerance in St. Augustinegrass. Moreover, results presented here should aid in the development of protocols for selection of freeze tolerant breeding materials under controlled environmental conditions. [ABSTRACT FROM AUTHOR]

Soil and foliar arthropod populations in agricultural settings respond to environmental disturbance and degradation, impacting functional biodiversity in agroecosystems. The objective of this study was to evaluate system level management effects on soil and foliar arthropod abundance and diversity in corn and soybean. Our field experiment was a completely randomized block design with three replicates for five farming systems which included: Conventional clean till, conventional long rotation, conventional no-till, organic clean till, and organic reduced till. Soil arthropod sampling was accomplished by pitfall trapping. Foliar arthropod sampling was accomplished by scouting corn and sweep netting soybean. Overall soil arthropod abundance was significantly impacted by cropping in corn and for foliar arthropods in soybeans. Conventional long rotation and organic clean till systems were highest in overall soil arthropod abundance for corn while organic reduced till systems exceeded all other systems for overall foliar arthropod abundance in soybeans. Foliar arthropod abundance over sampling weeks was significantly impacted by cropping system and is suspected to be the result of in-field weed and cover crop cultivation practices. This suggests that the sum of management practices within production systems impact soil and foliar arthropod abundance and diversity and that the effects of these systems are dynamic over the cropping season. Changes in diversity may be explained by weed management practices as sources of disturbance and reduced arthropod refuges via weed reduction. Furthermore, our results suggest agricultural systems lower in management intensity, whether due to organic practices or reduced levels of disturbance, foster greater arthropod diversity. [ABSTRACT FROM AUTHOR]

Genotype × environment interaction (G×E) can lead to diff erences in the performance of genotypes across environments. A G×E analysis can be used to analyze the stability of genotypes and the value of test locations. We developed a SAS program (SASG×E) that calculates univariate stability statistics, descriptive statistics, pooled and yearly ANOVA, genotypic and location variation, cluster analysis for location, and correlations among stability parameters. Univariate stability statistics calculated are Wricke's ecovalence (Wi2), Shukla's variance (si2), Lin and Binns cultivar superiority measure (Pi), Francis and Kannenberg coeffi cient of variation (CVi), Kang's yield stability statistic (YSi), Perkins and Jinks b (bi), regression slope (bi), and deviation from regression (Sd2). Other output includes input files for analyzing stability in R soft ware using AMMI and GGEBiplotGUI packages. SASG×E uses SAS programming language features (macro and structured query language [SQL]) for repetitive tasks, making it efficient and flexible for the simultaneous analysis of multiple dependent variables. SASG×E is free and intended for use by scientists studying the performance of polygenic or quantitative traits in multiple environments. The SASG×E program is presented here and is also available at http://cuke.hort.ncsu.edu/cucurbit/wehner/soft ware.html. [ABSTRACT FROM AUTHOR]

Marker assisted selection (MAS) has not been initiated in tomato (Solanum lycopersicum L.) for septoria leaf spot (SLS) resistance caused by Septoria lycopersici Speg due to lack of molecular markers. We studied the inheritance of SLS resistance and identified molecular markers linked to SLS resistance using bulked segregant analysis (BSA) in a segregating F2 population. Tomato inbred lines, NC 85L-1W (2007), susceptible to SLS and NC 839-2(2007)-1, resistant to SLS were used to develop the segregating population. A total of 250 F2 plants, and 10 plants each of P1, P2 and F1 were grown at the Mountain Horticultural Crops Research and Extension Center (MHCREC), Mills River NC in the summer of 2009. Disease severity was scored using a scale of 0 to 5, where 0 = no disease and 5 = complete development of disease. DNA was extracted from 2-3 week old plants and parental lines were screened with a total of 197 random amplified polymorphic DNA (RAPD) primers, of which 34 were polymorphic. Two DNA bulks, called resistant bulk (RB) and susceptible bulk (SB) were prepared from the F2 individuals. The RB and SB consisted of 8 individuals each with disease scores of 0, and 4.0 or 4.5, respectively. The segregation ratio of resistant and susceptible plants in F2 generation fit the expected Mendelian ratio of 3:1 for a single dominant gene. Five RAPD markers were linked to the SLS disease reaction, of which two were linked to susceptibility and three to the resistance. Subject to verification in independent populations, these markers may be useful for MAS of SLS resistance in tomato. [ABSTRACT FROM AUTHOR]

Background: The mosquitoes Aedes aegypti and Aedes albopictus are vectors of pathogenic viruses that cause major human illnesses including dengue, yellow fever and chikungunya. Both mosquito species are expanding their geographic distributions and now occur worldwide in temperate and tropical climates. Collection of eggs in oviposition traps (ovitraps) is commonly used for monitoring and surveillance of container-inhabiting Aedes populations by public health agencies charged with managing mosquito-transmitted illness. Addition of an organic infusion in these traps increases the number of eggs deposited. Gravid females are guided to ovitraps by volatile chemicals produced from the breakdown of organic matter by microbes. Methods: We previously isolated and cultured 14 species of bacteria from attractive experimental infusions, made from the senescent leaves of canebrake bamboo (Arundinaria gigantea). Cultures were grown for 24 h at 28 °C with constant shaking (120 rpm) and cell densities were determined with a hemocytometer. Behavioral responses to single bacterial isolates and to a mix of isolates at different cell densities were evaluated using two-choice sticky-screen bioassay methods with gravid Ae. aegypti and Ae. albopictus. Results: In behavioral assays of a mix of 14 bacterial isolates, significantly greater attraction responses were exhibited by Ae. aegypti and Ae. albopictus to bacterial densities of 107 and 108 cells/mL than to the control medium. When we tested single bacterial isolates, seven isolates (B1, B2, B3, B5, B12, B13 and B14) were significantly attractive to Ae. aegypti, and six isolates (B1, B5, B7, B10, B13 and B14) significantly attracted Ae. albopictus. Among all the isolates tested at three different cell densities, bacterial isolates B1, B5, B13 and B14 were highly attractive to both Aedes species. Conclusions: Our results show that at specific cell densities, some bacteria significantly influence the attraction of gravid Ae. aegypti and Ae. albopictus females to potential oviposition sites. Attractive bacterial isolates, when formulated for sustained release of attractants, could be coupled with an ovitrap containing a toxicant to achieve area-wide management of Aedes mosquitoes. [ABSTRACT FROM AUTHOR]

Demand for agricultural production systems that are both economically viable and environmentally conscious continues to increase. In recent years, reduced tillage systems, and grass and pasture rotations have been investigated to help maintain or improve soil quality, increase crop yield, and decrease labor requirements for production. However, documentation of the effects of reduced tillage, fescue rotation systems as well as other management practices, including pesticides, on pest damage and soil arthropod activity in peanut production for the Mid-Atlantic US region is still limited. Therefore, this project was implemented to assess impacts of fescue-based rotation systems on pests and other soil organisms when compared with cash crop rotation systems over four locations in eastern North Carolina. In addition, the effects of tillage (strip vs. conventional) and soil chlorpyrifos application on pod damage and soil-dwelling organisms were also evaluated. Soil arthropod populations were assessed by deploying pitfall traps containing 50% ethanol in each of the sampled plots. Results from the present study provide evidence that location significantly impacts pest damage and soil arthropod diversity in peanut fields. Cropping history also influenced arthropod diversity, with higher diversity in fescue compared with cash crop fields. Corn rootworm damage to pods was higher at one of our locations (Rocky Mount) compared with all others. Cropping history (fescue vs. cash crop) did not have an effect on rootworm damage, but increased numbers of hymenopterans, acarina, heteropterans, and collembolans in fescue compared with cash crop fields. Interestingly, there was an overall tendency for higher number of soil arthropods in traps placed in chlorpyrifos-treated plots compared with nontreated controls. [ABSTRACT FROM AUTHOR]

In this study we examined the effects of two quantitative trait loci (QTL) for southern leaf blight (SLB) resistance on several agronomic traits including disease resistance and yield. B73-3B and B73-6A are two near-isogenic lines (NILs) in the background of the maize (Zea mays L.) inbred B73, each carrying one introgression (called 3B and 6A respectively) encompassing a QTL for SLB resistance. Sets of isohybrid triplets were developed by crossing B73, B73-3B, and B73-6A to several inbred lines. A subset of these triplets for which the B73-3B and/or B73-6A hybrid was significantly more SLB resistant than the B73 check hybrid was selected and assessed in multi-environment yield trials with and without disease. In the presence of SLB, 3B was associated with an approximately 3% yield increase over B73. 6A was associated with a yield advantage in the presence of SLB in specific pedigrees where the 6A resistance phenotype was highly expressed. Results suggested that both introgressions might confer a yield cost in the absence of SLB, but only introgression 6A was associated with a statistically significant reduction. We present evidence to suggest that the yield cost is associated with the resistance phenotype rather than with linkage drag. [ABSTRACT FROM AUTHOR]

Among agricultural workers, migrant and seasonal farmworkers have been recognized as a special risk population because these laborers encounter cultural challenges and linguistic barriers while attempting to maintain their safety and health within their working environments. The crop-specificPesticides and Farmworker Health Toolkit(Toolkit) is a pesticide safety and health curriculum designed to communicate to farmworkers pesticide hazards commonly found in their working environments and to address Worker Protection Standard (WPS) pesticide training criteria for agricultural workers. The goal of this preliminary study was to test evaluation items for measuring knowledge increases among farmworkers and to assess the effectiveness of theToolkitin improving farmworkers’ knowledge of key WPS and risk communication concepts when theToolkitlesson was delivered by trained trainers in the field. After receiving training on the curriculum, four participating trainers provided lessons using theToolkitas part of their regular training responsibilities and orally administered a pre- and post-lesson evaluation instrument to 20 farmworker volunteers who were generally representative of the national farmworker population. Farmworker knowledge of pesticide safety messages significantly (P <.05) increased after participation in the lesson. Further, items with visual alternatives were found to be most useful in discriminating between more and less knowledgeable farmworkers. The pilot study suggests that thePesticides and Farmworker Health Toolkitis an effective, research-based pesticide safety and health intervention for the at-risk farmworker population and identifies a testing format appropriate for evaluating theToolkitand other similar interventions for farmworkers in the field. [ABSTRACT FROM AUTHOR]

Soybean [Glycine max (L.) Merr.] oil normally contains 2 to 4% stearic acid. Oil with higher levels of stearic acid is desired for use in the baking industry for both its chemical properties and human health benefits. Several lines with increased stearic acid have been identified; however, the agronomic consequences of high seed stearic acid are poorly understood. This study evaluates the effects of high stearic acid mutant alleles for two different Δ9-stearoylacyl carrier protein-desaturase genes, SACPDB and SACPD-C, on agronomic performance. Fifty F2-derived lines developed in a previous study were evaluated in a germination chamber and two field environments. Lines were either homozygous for the SACPD-C fasnc allele previously identified in FAM94-41, homozygous for the SACPD-B fas2nc allele from the induced 'Holladay' mutant TCJWB03-806-7-19, homozygous for both mutant genes, or homozygous wild-type for both genes. SACPD-C mutant lines were agronomically indistinguishable from the wild-type lines and yielded as well (3534 vs. 3414 kg ha-1). SACPD-B mutant lines suffered from a decreased seedling growth rate, were 15% shorter at maturity, had a 4% seed size reduction, and yielded 6% less than the wild-type lines. The different agronomic performance between SACPD-C and SACPD-B mutant lines was attributed to altered fatty acid composition in vegetative tissues of the SACPD-B mutant lines. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) affects whole spikes of small grain plants, yet little is known about how FHB develops following infection, or about the concentration or progression of the mycotoxin deoxynivalenol (DON) in non-grain spike tissues. Fusarium mycotoxin levels in whole small-grain spikes are of concern to producers of whole-crop silage, as well as users of straw containing chaff for animal bedding or winter livestock rations. A 2-year field experiment was performed in Kinston, NC to reveal the time course of FHB development. Eight winter wheat cultivars with varying levels of FHB resistance were used in the 2006 experiment, and four of them were used in 2007. Plots were spray-inoculated with Fusarium graminearum macroconidia at mid-anthesis. Four durations of post-anthesis mist were applied: 0, 10, 20, or 30 days. Spike samples were collected and bulked by plot at 15, 25, 35, 45, 55, and 65 days after anthesis (daa); samples were separated into grain, glume, and rachis fractions. Increasing durations of post-anthesis moisture elevated grain DON and reduced the effect of cultivar on DON, presumably by affecting the expression of resistance, in all spike tissues. fksanwm-damaged kernels increased from early kernel-hard to harvest-ripe in both years. Percent infected kernels increased from medium-milk to harvest-ripe. During grain-fill, DON concentrations declined in grain but increased in rachises and glumes, peaking at early kernel-hard, before declining. Higher mean and maximum DON levels were observed in rachises and glumes than in grain. Estimated whole-spike DON peaked at early kernel-hard. In a high-FHB year, whole-plant harvest for forage should be conducted as early as possible. Straw that may be consumed by livestock could contain significant amounts of DON in chaff, and DON can be minimized if straw is sourced from low-symptom crops. Cultivar FHB resistance ratings and disease data should be useful in predicting whole-spike DON levels. Overall, associations between grain DON levels in harvest-ripe and prior samples were stronger the later the prior samples were collected, suggesting limits to the possibility of predicting harvest-ripe grain DON from earlier levels. [ABSTRACT FROM AUTHOR]

The MEPDG (ARA, Inc., "NCHRP 1-37A Final Report: Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures," NCHRP Program 1-37,4 Project, National Research Council, Washington, D.C., 2004) introduces the dynamic modulus as the material property to characterize asphalt concrete. One of the challenges of acquiring the dynamic modulus from existing pavements is the standard dimensions of the test specimen. The specimen size specified in AASHTO TP62-07 (2007, "Standard Method of Test for Determining Dynamic Modulus of Hot-Mix Asphalt Concrete Mixtures," AASHTO, Washington, D.C.) cannot be obtained from many pavement layers. This study evaluates two other geometries, indirect tension specimens and prismatic specimens, to determine whether the measured dynamic modulus is the same as the modulus obtained from TP62 protocol. This study provides a comparison of the effects of a non-uniform state of stress and anisotropy. These effects are isolated by comparing specimens prepared by Superpave gyratory compaction and vibratory steel-wheel compaction. The comparisons are verified using four 12.5-mm surface course mixtures with different aggregate shapes and binder types, and one 25.0-mm base mixture. The results show that the difference between the dynamic modulus values obtained from different geometries is statistically insignificant. The results provide justification for using alternative methods for acquiring the dynamic modulus experimentally--specifically, for previously constructed pavements. [ABSTRACT FROM AUTHOR]

1. The insect Heliothis subflexa Guenée is a specialist on plants in the genus Physalis. In the present study, the physical response of Physalis leaves to egg deposition by H. subflexa is described. 2. It was observed that the leaves of Physalis plants respond to the eggs of H. subflexa, while co-occurring non-host plants do not. Leaves of Physalis angulata L. and Physalis pubescens L. respond to H. subflexa eggs by the formation of (i) necrotic tissue, (ii) undifferentiated cells that form a bump (neoplasm) under the eggs of this herbivore, or (iii) both types of responses. 3. Greenhouse experiments showed that 64% of eggs laid on P. angulata elicited a response, and that a response to an egg decreased the probability of hatching. Further experiments in the field with P. angulata showed that the mean response to eggs by leaves was 31%, and that this response increased as temperature increased. Field experiments also confirmed that a plant response to an egg decreased the probability of hatching and increased the probability of removal from the plant by physical dislodgement or predation. 4. Eggs that elicited a response had a 25% lower probability of hatching and a 28% lower probability of remaining on the plant, resulting in an average fitness cost of 19.3% for H. subflexa. This is the first study to show an induced direct physical defence of a plant against eggs of a noctuid moth. [ABSTRACT FROM AUTHOR]

Freshwater mussels fulfill an essential role in aquatic communities, but are also one of the most sensitive and rapidly declining faunal groups in North America. Rising water temperatures, caused by global climate change or industrial discharges, can further challenge impaired unionid communities, but thermal stress is almost certainly not the only stressor affecting freshwater mussels. Metals, such as copper (Cu), are a common source of toxicant exposure in aquatic environments. The toxic effects of Cu on the early life stages of freshwater mussels have been well studied, and freshwater mussels are more sensitive to Cu than most aquatic organisms. The purpose of the present study was to determine the effect of a sublethal copper concentration on the upper thermal tolerance of three species, Lampsilis siliquoidea, Potamilus alatus, and Ligumia recta, of juvenile freshwater mussels in 48- and 96-h tests. Thermal tolerance was determined over a range of experimental temperatures (20–42°C) at three acclimation temperatures (17, 22, and 27°C). Median lethal temperatures (LT50s) were calculated in the absence and presence of Cu, and at 48 h ranged from 34.6 to 44.4°C (mean 37.7°C) without Cu, and from 33.8 to 38.9°C (mean 35.8°C) with Cu. The LT50s at 96 h ranged from 32.5 to 35.6°C (mean 34.5°C) without Cu and from 33.0 to 35.4°C (mean 34.2°C) with Cu. Potamilus alatus had a significantly lower 48 h LT50 with Cu than without Cu at the 22°C acclimation temperature; there were no other significant differences in LT50s attributed to Cu. Survival trends showed limited evidence of interactive effects between copper and temperature for all three species, suggesting the combined stress of elevated temperatures and copper exposure to freshwater mussels should be further explored. Environ. Toxicol. Chem. 2010;29:691–699. © 2009 SETAC [ABSTRACT FROM AUTHOR]