OPTICAL SEED SORTER-BASED SELECTION LOWERS DEOXYNIVALENOL ACCUMULATION IN SOFT RED WINTER WHEAT

Fusarium head blight (FHB) of wheat (Triticum aestivum L.) results in discolored grain contaminated with deoxynivalenol (DON). DON accumulation, an indicator of FHB resistance, can be quantified and used as the basis for direct phenotypic selection, but testing is expensive. The primary objective of this study was to evaluate an optical seed sorter as an alternative to DON testing for FHB resistance breeding. Three hundred F4 derived soft red winter wheat (SRWW) breeding lines were grown in an inoculated FHB nursery over several years in Lexington, KY. Grain from each breeding line was sorted using an optical seed sorter calibrated to reject scabby (discolored) and accept non-scabby kernels. The percentage of fusarium damaged kernels estimated with the optical sorter (FDKos) was recorded for each breeding line, and accepted seed was used to plant subsequent generations. DON was lowered each cycle of optical sorter-based selection (lines with low FDKos were selected). Breeding lines were genotyped at loci on chromosomes 3BS, 2DL, and 5A using the following DNA markers: TaHRC, CFD233, and GWM304. Each cycle of optical sorter-based selection increased the percentage of lines with the resistant genotype at TaHRC. In other words, the sorter selected lines with Fhb1, a major effect FHB resistance QTL. Optical sorter-based selection also enhanced FHB resistance in several different marker genotype combinations. To evaluate optical sorter-augmented genomic selection (OSA-GS) for lower DON accumulation, six hundred thirty-eight University of Kentucky (UKY) breeding lines were genotyped using genotyping-by-sequencing (GBS) and grown in the FHB nursery. One hundred twenty of the F4 derived lines were also genotyped using GBS. FDKos data from the 120 F4 derived lines was used to train a genomic prediction model. Genomic estimated breeding values (GEBVs) for FDKos were computed for the UKY lines, then lines were selected based on FDKos GEBVs. OSA-GS lowered DON; moreover, using previously published cost estimates for the price of an optical sorter, DON analysis, and GBS, we determined that OSA-GS required less financial investment than direct phenotypic selection. Taken together, our findings indicate that the optical seed sorter has efficacy as a tool for FHB resistance breeding in SRWW

Combined effect of wind-forcing and isobath divergence on upwelling at Cape Bathurst, Beaufort Sea

Cape Bathurst is at the northeastern end of the Canadian Beaufort Shelf in the southeastern Beaufort Sea where the continental shelf abruptly ends at Amundsen Gulf. In this area, the steep slope east of the cape joins the relatively flat shelf immediately north of the cape leading to strong isobath divergence at the cape. Hydrographic and satellite data show upwelling of nutrient-rich, Pacific-origin water to the surface at Cape Bathurst when surface stress is upwelling-favorable for the Canadian Beaufort Shelf. We suggest that this enhanced upwelling is forced by the adjustment of the along-shelf flow (that is part of upwelling circulation) to the isobath divergence at the cape. Mooring and drifter data near Cape Bathurst also support this, showing swift, surface-intensified along-isobath flow during upwelling-favorable surface stress. Benthic samples near the cape show high numbers and diversity of organisms which suggest that nutrients brought to the surface by upwelling allow additional primary production in the region that ultimately feeds the benthos

Novel Mutations That Affect Stomata Development in \u3cem\u3eArabidopsis thaliana\u3c/em\u3e

Located on the epidermal surface of plants, stomata are small, pore-like structures that act as channels to exchange gas and water vapor between plant cells and the environment. Concentrations of gases and water within the plant cell are regulated through opening and closing of the stomata by turgor-driven movements. In Arabidopsis thaliana, development and differentiation of cells is controlled by the ERECTA (ER) family of genes (ERECTA, ERL1, and ERL2) which encode leucine-rich repeat-receptor-like kinases (LRR-RLKs). Acting synergistically, they direct cell division in different tissues and formation of stomata in epidermis. To better understand how ERECTA family genes regulate stomata development we conducted a forward genetic screen. Approximately 10,000 seeds of erl1erl2 were mutagenized using ethyl methanesulfonate (EMS). The M1 plants were grown and the M2 seeds were collected. Then, M2 seedlings were microscopically screened for stomata clustering. Two mutants, JMC19 and MC12 were chosen to pursue further because a high percentage of stomata in clusters was observed in their cotyledons. Both mutant lines were crossed with erl1erl2 in order to rid their genomes of other EMS induced mutations and to determine the nature of obtained mutations (recessive versus dominant; single or double). The phenotype of novel mutants (stomata index and stomata clustering) was compared to the erl1erl2. The two lines were also crossed with Col to see if the phenotype of novel mutations depended on erl1and/or erl2 mutations. After characterization of mutations, determining the location of the mutated JMC19 and MC12 genes through positional cloning is the next step. JMC19 and MC12 were crossed with Landsberg erecta (Ler) to analyze recombination frequency between mutant phenotype and a set of genetic markers. The frequency at which the mutant gene(s) recombined with markers on Ler chromosomes determined the location of the MC12. This method will also be used for JMC19 in the future. The overall goal of the study is to understand, through the use of forward genetics, the mechanism by which stomata are spaced and to identify the gene(s) that control this developmental process

Nitride Fuel Modeling Recommendation for Nitride Fuel Material Property Measurement Priority

The purpose of this effort was to provide the basis for a model that effectively predicts nitride fuel behavior. Material property models developed for the uranium nitride fuel system have been used to approximate the general behavior of nitride fuels with specific property models for the transuranic nitride fuels utilized as they become available. The AFCI fuel development program now has the means for predicting the behavior of the transuranic nitride fuel compositions. The key data and models needed for input into this model include: Thermal conductivity with burnup Fuel expansion coefficient Fuel swelling with burnup Fission gas release with burnup. Although the fuel performance model is a fully functional FEA analysis tool, it is limited by the input data and models

U.S./EURATOM INERI - Development of Inert Matrix Fuels for Plutonium and Minor Actinide Management in LWRs -- Fuel Requirements and Down-Select Report

This report documents the first milestone of the International Nuclear Energy Research Initiative (INERI) U.S./Canada Joint Proposal entitled “Development of Inert Matrix Fuels for Plutonium and Minor Actinide Management in Power Reactors.” The milestone represents the assessment and preliminary study of a variety of fuels that hold promise as transmutation and minor actinide burning fuel compositions for light water reactors. The most promising fuels of interest to the participants on this INERI program have been selected for further study. These fuel compositions are discussed in this report

AECL/U.S. INERI - Development of Inert Matrix Fuels for Plutonium and Minor Actinide Management in Power Reactors Fuel Requirements and Down-Select Report

This report documents the first milestone of the International Nuclear Energy Research Initiative (INERI) U.S./Euratom Joint Proposal 1.8 entitled “Development of Inert Matrix Fuels for Plutonium and Minor Actinide Management in Light-Water Reactors.” The milestone represents the assessment and preliminary study of a variety of fuels that hold promise as transmutation and minor actinide burning fuel compositions for light-water reactors. The most promising fuels of interest to the participants on this INERI program have been selected for further study. These fuel compositions are discussed in this report

Deterioration of perennial sea ice in the Beaufort Gyre from 2003 to 2012 and its impact on the oceanic freshwater cycle

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 1271-1305, doi:10.1002/2013JC008999.Time series of ice draft from 2003 to 2012 from moored sonar data are used to investigate variability and describe the reduction of the perennial sea ice cover in the Beaufort Gyre (BG), culminating in the extreme minimum in 2012. Negative trends in median ice drafts and most ice fractions are observed, while open water and thinnest ice fractions (<0.3 m) have increased, attesting to the ablation or removal of the older sea ice from the BG over the 9 year period. Monthly anomalies indicate a shift occurred toward thinner ice after 2007, in which the thicker ice evident at the northern stations was reduced. Differences in the ice characteristics between all of the stations also diminished, so that the ice cover throughout the region became statistically homogenous. The moored data are used in a relationship with satellite radiometer data to estimate ice volume changes throughout the BG. Summer solid fresh water content decreased drastically in consecutive years from 730 km3 in 2006 to 570 km3 in 2007, and to 240 km3 in 2008. After a short rebound, solid fresh water fell below 220 km3 in 2012. Meanwhile, hydrographic data indicate that liquid fresh water in the BG in summer increased 5410 km3 from 2003 to 2010 and decreased at least 210 km3 by 2012. The reduction of both solid and liquid fresh water components indicates a net export of approximately 320 km3 of fresh water from the region occurred between 2010 and 2012, suggesting that the anticyclonic atmosphere-ocean circulation has weakened.Support for Krishfield, Proshutinsky, and Timmermans, partial financial support of logistics, hydrographic observations on the board of Canadian icebreaker, and full financial coverage of all mooring instrumentation was provided by the National Science Foundation (under grants OPP-0230184, OPP-0424864, ARC-0722694, ARC-0806306, ARC- 0856531, ARC-1107277, and ARC- 1203720), and Woods Hole Oceanographic Institution internal funding. Funding for Tateyama was provided by the International Arctic Research Center – Japan Aerospace Exploration Agency (IJIS) Arctic project, and for Williams, Carmack, and McLaughlin by Fisheries and Oceans Canada

Arctic Ocean Microbial Community Structure before and after the 2007 Record Sea Ice Minimum

Increasing global temperatures are having a profound impact in the Arctic, including the dramatic loss of multiyear sea ice in 2007 that has continued to the present. The majority of life in the Arctic is microbial and the consequences of climate-mediated changes on microbial marine food webs, which are responsible for biogeochemical cycling and support higher trophic levels, are unknown. We examined microbial communities over time by using high-throughput sequencing of microbial DNA collected between 2003 and 2010 from the subsurface chlorophyll maximum (SCM) layer of the Beaufort Sea (Canadian Arctic). We found that overall this layer has freshened and concentrations of nitrate, the limiting nutrient for photosynthetic production in Arctic seas, have decreased. We compared microbial communities from before and after the record September 2007 sea ice minimum and detected significant differences in communities from all three domains of life. In particular, there were significant changes in species composition of Eukarya, with ciliates becoming more common and heterotrophic marine stramenopiles (MASTs) accounting for a smaller proportion of sequences retrieved after 2007. Within the Archaea, Marine Group I Thaumarchaeota, which earlier represented up to 60% of the Archaea sequences in this layer, have declined to <10%. Bacterial communities overall were less diverse after 2007, with a significant decrease of the Bacteroidetes. These significant shifts suggest that the microbial food webs are sensitive to physical oceanographic changes such as those occurring in the Canadian Arctic over the past decade

Deterioration of perennial sea ice in the Beaufort Gyre from 2003 to 2012 and its impact on the oceanic freshwater cycle

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 1271-1305, doi:10.1002/2013JC008999.Time series of ice draft from 2003 to 2012 from moored sonar data are used to investigate variability and describe the reduction of the perennial sea ice cover in the Beaufort Gyre (BG), culminating in the extreme minimum in 2012. Negative trends in median ice drafts and most ice fractions are observed, while open water and thinnest ice fractions (<0.3 m) have increased, attesting to the ablation or removal of the older sea ice from the BG over the 9 year period. Monthly anomalies indicate a shift occurred toward thinner ice after 2007, in which the thicker ice evident at the northern stations was reduced. Differences in the ice characteristics between all of the stations also diminished, so that the ice cover throughout the region became statistically homogenous. The moored data are used in a relationship with satellite radiometer data to estimate ice volume changes throughout the BG. Summer solid fresh water content decreased drastically in consecutive years from 730 km3 in 2006 to 570 km3 in 2007, and to 240 km3 in 2008. After a short rebound, solid fresh water fell below 220 km3 in 2012. Meanwhile, hydrographic data indicate that liquid fresh water in the BG in summer increased 5410 km3 from 2003 to 2010 and decreased at least 210 km3 by 2012. The reduction of both solid and liquid fresh water components indicates a net export of approximately 320 km3 of fresh water from the region occurred between 2010 and 2012, suggesting that the anticyclonic atmosphere-ocean circulation has weakened.Support for Krishfield, Proshutinsky, and Timmermans, partial financial support of logistics, hydrographic observations on the board of Canadian icebreaker, and full financial coverage of all mooring instrumentation was provided by the National Science Foundation (under grants OPP-0230184, OPP-0424864, ARC-0722694, ARC-0806306, ARC- 0856531, ARC-1107277, and ARC- 1203720), and Woods Hole Oceanographic Institution internal funding. Funding for Tateyama was provided by the International Arctic Research Center – Japan Aerospace Exploration Agency (IJIS) Arctic project, and for Williams, Carmack, and McLaughlin by Fisheries and Oceans Canada

Geochemistry of small Canadian Arctic rivers with diverse geological and hydrological settings

Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 125(1), (2020): e2019JG005414, doi:10.1029/2019JG005414.A survey of 25 coastal‐draining rivers across the Canadian Arctic Archipelago (CAA) shows that these systems are distinct from the largest Arctic rivers that drain watersheds extending far south of the Arctic circle. Observations collected from 2014 to 2016 illustrate the influences of seasonal hydrology, bedrock geology, and landscape physiography on each river's inorganic geochemical characteristics. Summertime data show the impact of coincident gradients in lake cover and surficial geology on river geochemical signatures. In the north and central CAA, drainage basins are generally smaller, underlain by sedimentary bedrock, and their hydrology is driven by seasonal precipitation pulses that undergo little modification before they enter the coastal ocean. In the southern CAA, a high density of lakes stores water longer within the terrestrial system, permitting more modification of water isotope and geochemical characteristics. Annual time‐series observations from two CAA rivers reveal that their concentration‐discharge relationships differ compared with those of the largest Arctic rivers, suggesting that future projections of dissolved ion fluxes from CAA rivers to the Arctic Ocean may not be reliably made based on compositions of the largest Arctic rivers alone, and that rivers draining the CAA region will likely follow different trajectories of change under a warming climate. Understanding how these small, coastal‐draining river systems will respond to climate change is essential to fully evaluate the impact of changing freshwater inputs to the Arctic marine system.This work was only possible through a network of enthusiastic and devoted collaborators. Partners included Polar Knowledge Canada and the Canadian High Arctic Research Station, the Arctic Research Foundation, the Kugluktuk Angoniatit Association, and the Canadian Arctic GEOTRACES Program. We acknowledge support from the Department of Fisheries and Oceans Canada, the Woods Hole Oceanographic Institution Coastal Ocean Institute, The G. Unger Vetlesen Foundation, Jane and James Orr, and the Woods Hole Research Center. Many thanks go to Austin Maniyogena, Angulalik Pedersen, Adrian Schimnowski, JS Moore, Les Harris, Oksana Schimnowski, as well as Barbara Adjun, Amanda Dumond, and Johnny Nivingalok, and the captains and crew of the research vessels CCGS Amundsen and R/V Martin Bergmann, all of whom supported our research and helped with sample collection. Special thanks also go to Valier Galy, Zhaohui “Aleck” Wang, Marty Davelaar, Michiyo Yamamoto‐Kawai, Hugh McLean, Mike Dempsey, Baba Pedersen, Maureen Soon, Katherine Hoering, Sean Sylva, Ekaterina Bulygina, and Anya Suslova for their invaluable contributions during field program planning, preparations, and laboratory analyses. Robert Max Holmes is thanked for many fruitful discussions. We also thank several anonymous reviewers for their helpful comments on the paper's content and structure. All of the data presented in this paper can be found at https://doi.org/10.1594/PANGAEA.908497