Agriculture Commons^™

Perennializing Marginal Croplands: Going Back To The Future To Mitigate Climate Change With Resilient Biobased Feedstocks, Salvador Ramirez Ii, Marty R. Schmer, Virginia L. Jin, Robert B. Mitchell, Catherine E. Stewart, Jay Parsons, Daren D. Redfearn, John J. Quinn, Gary E. Varvel, Kenneth P. Vogel, Ronald F. Follett

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Managing annual row crops on marginally productive croplands can be environmentally unsustainable and result in variable economic returns. Incorporating perennial bioenergy feedstocks into marginally productive cropland can engender ecosystem services and enhance climate resiliency while also diversifying farm incomes. We use one of the oldest bioenergy-specific field experiments in North America to evaluate economically and environmentally sustainable management practices for growing perennial grasses on marginal cropland. This long-term field trial called 9804 was established in 1998 in eastern Nebraska and compared the productivity and sustainability of corn (Zea mays L.)—both corn grain and corn stover—and switchgrass (Panicum virgatum …

First Draft Genome Of Thecaphora Frezii, Causal Agent Of Peanut Smut Disease, Renee S. Arias, Cinthia Conforto, Valerie A. Orner, Edgardo J. Carloni, Juan H. Soave, Alicia N. Massa, Marshall C. Lamb, Nelson Bernardi-Lima, Alejandro M. Rago

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Objectives: The fungal pathogen Thecaphora frezii Carranza & Lindquist causes peanut smut, a severe disease currently endemic in Argentina. To study the ecology of T. frezii and to understand the mechanisms of smut resistance in peanut plants, it is crucial to know the genetics of this pathogen. The objective of this work was to isolate the pathogen and generate the first draft genome of T. frezii that will be the basis for analyzing its potential genetic diversity and its interaction with peanut cultivars. Our research group is working to identify peanut germplasm with smut resistance and to understand the genetics …

Federal Agency Perspectives And Funding Opportunities For Weed And Invasive Plant Research, Stephen L. Young, James J. Kells, Vijay K. Nandula

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Weeds and invasive plants know no borders and have collectively impacted many ecosystems worldwide, including croplands, forests, grasslands, rangelands, wetlands, and riparian areas. Losses continue to mount, affecting yield and productivity, species diversity, and ecosystem services, with both short- and long-term repercussions on the sustainability of plant and animal communities and the livelihoods of many. New and emerging invasive plants, along with many of the most intractable weeds, have undermined even the best control efforts, serving as a reminder of the constant need for improvements in science, application, and technology. One of the main reasons for the success of weeds …

Agricultural Research Service Weed Science Research: Past, Present, And Future, Stephen L. Young, James V. Anderson, Scott R. Baerson, Joanna Bajsa-Hirschel, Dana M. Blumenthal, Chad S. Boyd, Clyde D. Boyette, Eric B. Brennan, Charles L. Cantrell, Wun S. Chao, Joanne C. Chee-Sanford, Charlie D. Clements, F. Allen Dray, Stephen O. Duke, Kayla M. Eason, Reginald S. Fletcher, Michael R. Fulcher, Brenda J. Grewell, Erik P. Hamerlynck, Robert E. Hoagland, David P. Horvath, Eugene P. Law, Daniel E. Martin, Clint Mattox, Steven B. Mirsky, Patrick J. Moran, Rebecca C. Mueller, Vijay K. Nandula, Beth A. Newingham, Zhiqiang Pan, Lauren M. Porensky, Paul D. Pratt, Andrew J. Price, Brian G. Rector, Krishna N. Reddy, Roger L. Sheley, Lincoln Smith, Melissa C. Smith, Keirith A. Snyder, Matthew A. Tancos

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) has been a leader in weed science research covering topics ranging from the development and use of integrated weed management (IWM) tactics to basic mechanistic studies, including biotic resistance of desirable plant communities and herbicide resistance. ARS weed scientists have worked in agricultural and natural ecosystems, including agronomic and horticultural crops, pastures, forests, wild lands, aquatic habitats, wetlands, and riparian areas. Through strong partnerships with academia, state agencies, private industry, and numerous federal programs, ARS weed scientists have made contributions to discoveries in the newest fields of robotics and genetics, as well …

Intensification Differentially Affects The Delivery Of Multiple Ecosystem Services In Subtropical And Temperate Grasslands, Shishir Paudel, Nuria Gomez-Casanovas, Elizabeth H. Boughton, Samuel D. Chamberlain, Pradeep Wagle, Brekke L. Peterson, Rajen Bajgain, Patrick J. Starks, Jefferey Basara, Carl J. Bernacchi, Evan H. Delucia, Laura E. Goodman, Prasanna H. Gowda, Ryan Reuter, Jed P. Sparks, Hilary M. Swain, Xiangming Xiao, Jean L. Steiner

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Intensification, the process of intensifying land management to enhance agricultural goods, results in “intensive” pastures that are planted with productive grasses and fertilized. These intensive pastures provide essential ecosystem services, including forage production for livestock. Understanding the synergies and tradeoffs of pasture intensification on the delivery of services across climatic regions is crucial to shape policies and incentives for better management of natural resources. Here, we investigated how grassland intensification affects key components of provisioning (forage productivity and quality), supporting (plant diversity) and regulating services (CO2 and CH4 fluxes) by comparing these services between intensive versus extensive pastures in subtropical …

Two Qtls Govern The Resistance To Sclerotinia Minor In An Interspecific Peanut Ril Population, Melina H. Rosso, Francisco J. De Blas, Alicia N. Massa, Claudio Oddino, Damian F. Giordano, Jose G. Seijo, Renee S. Arias, Juan H. Soave, Sara J. Soave, Mario I. Buteler, Marina Bressano

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Sclerotinia blight is a soilborne disease caused by Sclerotinia minor Jagger and can produce severe decrease in yield. Cultural management strategies and chemical treatment are not completely effective; therefore, growing peanut-resistant varieties is likely to be the most effective control method for this disease. Sclerotinia blight resistance has been identified in wild Arachis species and further transferred to peanut elite cultivars. To identify the genome regions conferring Sclerotinia blight resistance within a tetraploid genetic background, this study evaluated a population of recombinant inbred lines (RIL) with introgressed genes from three wild diploid species: A. cardenasii, A. correntina, and A. batizocoi. …

The Impact Of Crop Rotation And Spatially Varying Crop Parameters In The E3sm Land Model (Elmv2), Eva Sinha, Ben Bond-Lamberty, Katherine V. Calvin, Beth A. Drewniak, Gautam Bisht, Carl Bernacchi, Bethany J. Blakely, Caitlin E. Moore

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Earth System Models (ESMs) are increasingly representing agriculture due to its impact on biogeochemical cycles, local and regional climate, and fundamental importance for human society. Realistic large scale simulations may require spatially varying crop parameters that capture crop growth at various scales and among different cultivars, as well as common crop management practices, but their importance is uncertain, and they are often not represented in ESMs. In this study, we examine the impact of using constant versus spatially varying crop parameters using a novel, realistic crop rotation scenario in the Energy Exascale Earth System Model (E3SM) Land Model version 2 …

Climate And Pest Interactions Pose A Cross-Landscape Management Challenge To Soil And Water Conservation, Joshua W. Campbell, Michael R. Fulcher, Brenda J. Grewell, Stephen L. Young

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Climate change and biological invasions by plant pests (weeds), agriculture and forest insect pests (insects), and microbial pests (plant pathogens) are complex interactive components of global environmental change. The influence of pest distribution and prevalence across landscapes are challenging the conservation and sustainability of natural resources, agricultural production, native biological diversity, and the valuable ecosystem services they provide (Huenneke 1997; Vitousek 1997; Juroszek and von Tiedemann 2013; Ziska and Dukes 2014). Since 2000, numerous scientific studies indicate accelerating climate change is posing substantial risks to natural and managed systems in North America (IPPC 2022). Intensified droughts, largescale wildfires, and increased …

Invasive Annual Grasses—Reenvisioning Approaches In A Changing Climate, David Archer, David Toledo, Dana M. Blumenthal, Justin Derner, Usda Ars Burns, Oregon, Kirk Davies, Erik Hamerlynck, Roger Sheley, Pat Clark, Fred Pierson, Charlie Clements, Beth Newingham, Brian Rector, John Gaskin, Carissa L. Wonkka, Kevin Jensen, Tom Monaco, Lance T. Vermeire, Stephen L. Young

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

For nearly a century, invasive annual grasses have increasingly impacted terrestrial ecosystems across the western United States. Weather variability associated with climate change and increased atmospheric carbon dioxide (CO2) are making even more difficult the challenges of managing invasive annual grasses. As part of a special issue on climate change impacts on soil and water conservation, the topic of invasive annual grasses is being addressed by scientists at the USDA Agricultural Research Service to emphasize the need for additional research and future studies that build on current knowledge and account for (extreme) changes in abiotic and biotic conditions. Much research …

Leaf, Plant, To Canopy: A Mechanistic Study On Aboveground Plasticity And Plant Density Within A Maize–Soybean Intercrop System For The Midwest, Usa, Elena A. Pelech, Jochem B. Evers, Taylor L. Pederson, David W. Drag, Peng Fu, Carl J. Bernacchi

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Plants have evolved to adapt to their neighbours through plastic trait responses. In intercrop systems, plant growth occurs at different spatial and temporal dimensions, creating a competitive light environment where aboveground plasticity may support complementarity in light-use efficiency, realizing yield gains per unit area compared with monoculture systems. Physiological and architectural plasticity including the consequences for light-use efficiency and yield in a maize-soybean solar corridor intercrop system was compared, empirically, with the standard monoculture systems of the Midwest, USA. The impact of reducing maize plant density on yield was investigated in the following year. Intercropped maize favoured physiological plasticity over …

Optimal Stomatal Theory Predicts Co2 Responses Of Stomatal Conductance In Both Gymnosperm And Angiosperm Trees, Anna Gardner, Mingkai Jiang, David S. Ellsworth, A. Robert Mackenzie, Jeremy Pritchard, Martin Karl Friedrich Bader, Craig V.M. Barton, Carl Bernacchi, Carlo Calfapietra, Kristine Y. Crous, Mirindi Eric Dusenge, Teresa E. Gimeno, Marianne Hall, Shubhangi Lamba, Sebastian Leuzinger, Johan Uddling, Jeffrey Warren, Göran Wallin, Belinda E. Medlyn

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Optimal stomatal theory predicts that stomata operate to maximise photosynthesis (Anet) and minimise transpirational water loss to achieve optimal intrinsic water-use efficiency (iWUE). We tested whether this theory can predict stomatal responses to elevated atmospheric CO2 (eCO2), and whether it can capture differences in responsiveness among woody plant functional types (PFTs). We conducted a meta-analysis of tree studies of the effect of eCO2 on iWUE and its components Anet and stomatal conductance (gs). We compared three PFTs, using the unified stomatal optimisation (USO) model to account for confounding effects of leaf–air vapour pressure difference (D). We expected smaller gs, but …

Modeling Perennial Bioenergy Crops In The E3sm Land Model (Elmv2), Eva Sinha, Katherine V. Calvin, Ben Bond-Lamberty, Beth A. Drewniak, Daniel M. Ricciuto, Khachik Sargsyan, Yanyan Cheng, Carl Bernacchi, Caitlin E. Moore

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Perennial bioenergy crops are increasingly important for the production of ethanol and other renewable fuels, and as part of an agricultural system that alters the climate through its impact on biogeophysical and biogeochemical properties of the terrestrial ecosystem. Few Earth System Models (ESMs) represent such crops, however. In this study, we expand the Energy Exascale Earth System Land Model to include perennial bioenergy crops with a high potential for mitigating climate change. We focus on high-productivity miscanthus and switchgrass, estimating various parameters associated with their different growth stages and performing a global sensitivity analysis to identify and optimize these parameters. …

First Draft Genome And Transcriptome Of Cercosporidium Personatum, Causal Agent Of Late Leaf Spot Disease Of Peanut, Renee Arias, John T. Dobbs, Jane E. Stewart, Emily G. Cantonwine, Valerie A. Omer, Victor S. Sobolev, Marshall C. Lamb, Alicia Massa

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Objective Two main fungal leaf spot diseases occur in peanut, namely early leaf spot (ELS) and late leaf spot (LLS), these cause a yearly average of $44 million losses. Limited genetic information, 3534 bp of sequencing, exists about the causal agent of LLS, Cercosporidium personatum (syn. Nothopassalora personata, syn. Phaeoisariopsis personata). The extremely slow growth of this fungus, approximately 1 cm colony in 6 months, and challenges in nucleic acid extractions have hindered research on LLS. Our goal in this work is to provide a reference genome for research on this pathogen.

Results Whole genome and transcriptome sequencing of the …

Increased Bundle-Sheath Leakiness Of Co2 During Photosynthetic Induction Shows A Lack Of Coordination Between The C4 And C3 Cycles, Yu Wang, Samantha S. Stutz, Carl J. Bernacchi, Ryan A. Boyd, Donald R. Ort, Stephen P. Long

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Use of a complete dynamic model of NADP-malic enzyme C4 photosynthesis indicated that, during transitions from dark or shade to high light, induction of the C4 pathway was more rapid than that of C3, resulting in a predicted transient increase in bundle-sheath CO2 leakiness (ϕ). Previously, ϕ has been measured at steady state; here we developed a new method, coupling a tunable diode laser absorption spectroscope with a gas-exchange system to track ϕ in sorghum and maize through the nonsteady-state condition of photosynthetic induction. In both species, ϕ showed a transient increase to > 0.35 before declining to a steady state …

Removal Of Redox-Sensitive Rubisco Activase Does Not Alter Rubisco Regulation In Soybean, Christopher M. Harvey, Amanda P. Cavanagh, Sang Yeol Kim, David A. Wright, Ron G. Edquilang, Kayla S. Shreeves, Juan Alejandro Perdomo, Martin H. Spalding, Donald R. Ort, Carl J. Bernacchi, Steven C. Huber

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Rubisco activase (Rca) facilitates the catalytic repair of Rubisco, the CO2-fixing enzyme of photosynthesis, following periods of darkness, low to high light transitions or stress. Removal of the redox-regulated isoform of Rubisco activase, Rca-α, enhances photosynthetic induction in Arabidopsis and has been suggested as a strategy for the improvement of crops, which may experience frequent light transitions in the field; however, this has never been tested in a crop species. Therefore, we used RNAi to reduce the Rca-α content of soybean (Glycine max cv. Williams 82) below detectable levels and then characterized the growth, photosynthesis, and Rubisco activity of the …

Difference In Seasonal Peak Timing Of Soybean Far-Red Sif And Gpp Explained By Canopy Structure And Chlorophyll Content, Genghong Wu, Chongya Jiang, Hyungsuk Kimm, Sheng Wang, Carl Bernacchi, Caitlin E. Moore, Andy Suyker, Xi Yang, Troy Magney, Christian Frankenberg, Youngryel Ryu, Benjamin Dechant, Kaiyu Guan

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Recent advances in remotely sensed solar-induced chlorophyll fluorescence (SIF) have provided an exciting and promising opportunity for estimating gross primary production (GPP). Previous studies mainly focused on the linear correlation between SIF and GPP and the slope of the SIF-GPP relationship, both of which lack rigorous consideration of the seasonal trajectories of SIF and GPP. Here, we investigated the timing of seasonal peaks of far-red SIF and GPP in soybean fields by integrating tower data, satellite data, and process-based Soil Canopy Observation of Photosynthesis and Energy (SCOPE, v2.0) model simulations. We found inconsistency between the seasonal peak timing of far-red …

Patch-Burn Grazing Impacts Forage Resources In Subtropical Humid Grazing Lands, Elizabeth H. Boughton, Nuria Gomez-Casanovas, Hilary Swain, Carl Bernacchi, Raoul K. Boughton, Keith Brinsko, Haoyu Li, Alan Rivero, Evan H. Delucia, Jed Sparks

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Subtropical humid grazing lands represent a large global land use and are important for livestock production, as well as supplying multiple ecosystem services. Patch-burn grazing (PBG) management is applied in temperate grazing lands to enhance environmental and economic sustainability; however, this management system has not been widely tested in subtropical humid grazing lands. The objective of this study was to determine how PBG affected forage resources, in comparison with the business-as-usual full-burn (FB) management in both intensively managed pastures (IMP) and seminative (SN) pastures in subtropical humid grazinglands. We hypothesized that PBG management would create patch contrasts in forage quantity …

Attributing Differences Of Solar-Induced Chlorophyll Fluorescence (Sif)-Gross Primary Production (Gpp) Relationships Between Two C4 Crops: Corn And Miscanthus, Genghong Wu, Kaiyu Guan, Chongya Jiang, Hyungsuk Kimm, Guofang Miao, Carl J. Bernacchi, Caitlin E. Moore, Elizabeth A. Ainsworth, Xi Yang, Joseph A. Berry, Christian Frankenberg, Min Chen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

There remains limited information to characterize the solar-induced chlorophyll fluorescence (SIF)-gross primary production (GPP) relationship in C4 cropping systems. The annual C4 crop corn and perennial C4 crop miscanthus differ in phenology, canopy structure and leaf physiology. Investigating the SIF-GPP relationships in these species could deepen our understanding of SIF-GPP relationships within C4 crops. Using in situ canopy SIF and GPP measurements for both species along with leaf-level measurements, we found considerable differences in the SIF-GPP relationships between corn and miscanthus, with a stronger SIF-GPP relationship and higher slope of SIF-GPP observed in corn compared to miscanthus. These differences were …

High-Throughput Characterization, Correlation, And Mapping Of Leaf Photosynthetic And Functional Traits In The Soybean (Glycine Max) Nested Association Mapping Population, Christopher M. Montes, Carolyn Fox, Álvaro Sanz-Sáez, Shawn P. Serbin, Etsushi Kumagai, Matheus D. Krause, Alencar Xavier, James E. Specht, William D. Beavis, Carl J. Bernacchi, Brian W. Diers, Elizabeth A. Ainsworth

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Photosynthesis is a key target to improve crop production in many species including soybean [Glycine max (L.) Merr.]. A challenge is that phenotyping photosynthetic traits by traditional approaches is slow and destructive. There is proof-of-concept for leaf hyperspectral reflectance as a rapid method to model photosynthetic traits. However, the crucial step of demonstrating that hyperspectral approaches can be used to advance understanding of the genetic architecture of photosynthetic traits is untested. To address this challenge, we used full-range (500-2,400 nm) leaf reflectance spectroscopy to build partial least squares regression models to estimate leaf traits, including the rate-limiting processes of photosynthesis, …

Advances In Field-Based High-Throughput Photosynthetic Phenotyping, Peng Fu, Christopher M. Montes, Matthew H. Siebers, Nuria Gomez-Casanovas, Justin M. Mcgrath, Elizabeth A. Ainsworth, Carl J. Bernacchi

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Gas exchange techniques revolutionized plant research and advanced understanding, including associated fluxes and efficiencies, of photosynthesis, photorespiration, and respiration of plants from cellular to ecosystem scales. These techniques remain the gold standard for inferring photosynthetic rates and underlying physiology/biochemistry, although their utility for high-throughput phenotyping (HTP) of photosynthesis is limited both by the number of gas exchange systems available and the number of personnel available to operate the equipment. Remote sensing techniques have long been used to assess ecosystem productivity at coarse spatial and temporal resolutions, and advances in sensor technology coupled with advanced statistical techniques are expanding remote sensing …

Development Of A Data-Assimilation System To Forecast Agricultural Systems: A Case Study Of Constraining Soil Water And Soil Nitrogen Dynamics In The Apsim Model, Marissa S. Kivi, Bethany Blakely, Michael Masters, Carl J. Bernacchi, Fernando E. Miguez, Hamze Dokoohaki

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

As we face today's large-scale agricultural issues, the need for robust methods of agricultural forecasting has never been clearer. Yet, the accuracy and precision of our forecasts remains limited by current tools and methods. To overcome the limitations of process-based models and observed data, we iteratively designed and tested a generalizable and robust data-assimilation system that systematically constrains state variables in the APSIM model to improve forecast accuracy and precision. Our final novel system utilizes the Ensemble Kalman Filter to constrain model states and update model parameters at observed time steps and incorporates an algorithm that improves system performance through …

Linking Soil Microbial Community Structure To Potential Carbon Mineralization: A Continental Scale Assessment Of Reduced Tillage, Elizabeth L. Rieke, Shannon B. Cappellazzi, Michael Cope, Daniel Liptzin, G. Mac Bean, Kelsey L.H. Greub, Charlotte E. Norris, Paul W. Tracy, Ezra Aberle, Amanda Ashworth, Oscar Bañuelos Tavarez, Andy I. Bary, R. L. Baumhardt, Alberto Borbón Gracia, Daniel C. Brainard, Jameson R. Brennan, Dolores Briones Reyes, Darren Bruhjell, Cameron N. Carlyle, James J.W. Crawford, Cody F. Creech, Steve W. Culman, Bill Deen, Curtis J. Dell, Justin D. Derner, Thomas F. Ducey, Sjoerd W. Duiker, Miles F. Dyck, Benjamin H. Ellert, Avelino Espinosa Solorio, Steven J. Fonte, Simon Fonteyne, Ann Marie Fortuna, Jamie L. Foster, Lisa M. Fultz, Audrey V. Gamble, Charles M. Geddes, Deirdre Griffin-Lahue, John H. Grove, Stephen K. Hamilton

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical …

A Generalist–Specialist Trade-Off Between Switchgrass Cytotypes Impacts Climate Adaptation And Geographic Range, Joseph D. Napier, Paul P. Grabowski, John T. Lovell, Jason Bonnette, Sujan Mamidi, Maria Jose Gomez-Hughes, Acer Vanwallendael, Xiaoyu Weng, Lori H. Handley, Min K. Kim, Arvid R. Boe, Philip A. Fay, Felix B. Fritschi, Julie D. Jastrow, John Lloyd-Reilley, David B. Lowry, Roser Matamala, Robert B. Mitchell, Francis M. Rouquette, Yanqi Wu, Jenell Webber, Teresa Jones, Kerrie Barry, Jane Grimwood, Jeremy Schmutz, Thomas E. Juenger

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Polyploidy results from whole-genome duplication and is a unique form of heritable variation with pronounced evolutionary implications. Different ploidy levels, or cytotypes, can exist within a single species, and such systems provide an opportunity to assess how ploidy variation alters phenotypic novelty, adaptability, and fitness, which can, in turn, drive the development of unique ecological niches that promote the coexistence of multiple cytotypes. Switchgrass, Panicum virgatum, is a widespread, perennial C4 grass in North America with multiple naturally occurring cytotypes, primarily tetraploids (4×) and octoploids (8×). Using a combination of genomic, quantitative genetic, landscape, and niche modeling approaches, we detect …

Alternative Pathway To Photorespiration Protects Growth And Productivity At Elevated Temperatures In A Model Crop, Amanda P. Cavanagh, Paul F. South, Carl J. Bernacchi, Donald R. Ort

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Adapting crops to warmer growing season temperatures is a major challenge in mitigating the impacts of climate change on crop production. Warming temperatures drive greater evaporative demand and can directly interfere with both reproductive and vegetative physiological processes. Most of the world’s crop species have C3 photosynthetic metabolism for which increasing temperature means higher rates of photorespiration, wherein the enzyme responsible for fixing CO2 fixes O2 instead followed by an energetically costly recycling pathway that spans several cell compartments. In C3 crops like wheat, rice and soybean, photorespiration translates into large yield losses that are predicted to increase as global …

Transformation Of Major Peanut (Arachis Hypogaea) Stilbenoid Phytoalexins Caused By Selected Microorganisms, Victor S. Sobolev, Travis E. Walk, Renee S. Arias, Alicia N. Massa, Valerie A. Orner, Marshall C. Lamb

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The peanut plant accumulates defensive stilbenoid phytoalexins in response to the presence of soil fungi, which in turn produce phytoalexin-detoxifying enzymes for successfully invading the plant host. Aspergillus spp. are opportunistic pathogens that invade peanut seeds; most common fungal species often produce highly carcinogenic aflatoxins. The purpose of the present research was to evaluate the in vitro dynamics of peanut phytoalexin transformation/detoxification by important fungal species. This work revealed that in feeding experiments, Aspergillus spp. from section Flavi were capable of degrading the major peanut phytoalexin, arachidin-3, into its hydroxylated homolog, arachidin-1, and a benzenoid, SB-1. However, Aspergillus niger from …

Drought Imprints On Crops Can Reduce Yield Loss: Nature's Insights For Food Security, Peng Fu, Deepak Jaiswal, Justin M. Mcgrath, Shaowen Wang, Stephen P. Long, Carl J. Bernacchi

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The Midwestern “Corn-Belt” in the United States is the most productive agricultural region on the planet despite being predominantly rainfed. In this region, global climate change is driving precipitation patterns toward wetter springs and drier mid- to late-summers, a trend that is likely to intensify in the future. The lack of precipitation can lead to crop water limitations that ultimately impact growth and yields. Young plants exposed to water stress will often invest more resources into their root systems, possibly priming the crop for any subsequent mid- or late-season drought. The trend toward wetter springs, however, suggests that opportunities for …

Impact Of Harvest On Switchgrass Leaf Microbial Communities, Esther Singer, Elizabeth M. Carpenter, Jason Bonnette, Tanja Woyke, Thomas E. Juenger

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Switchgrass is a promising feedstock for biofuel production, with potential for leveraging its native microbial community to increase productivity and resilience to environmental stress. Here, we characterized the bacterial, archaeal and fungal diversity of the leaf microbial community associated with four switchgrass (Panicum virgatum) genotypes, subjected to two harvest treatments (annual harvest and unharvested control), and two fertilization levels (fertilized and unfertilized control), based on 16S rRNA gene and internal transcribed spacer (ITS) region amplicon sequencing. Leaf surface and leaf endosphere bacterial communities were significantly different with Alphaproteobacteria enriched in the leaf surface and Gammaproteobacteria and Bacilli enriched in the …

Patterning Ecological Restoration After Weeds, Stephen L. Young, Erik P. Hamerlynck

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The United Nations Decade on Ecosystem Restoration aims to prevent, halt, and reverse the degradation of ecosystems on every continent. Disturbances stemming from anthropogenic or natural causes make plant community restoration challenging. The introduction of fast-growing weeds that generate high biomass and produce copious seed is most threatening to plant communities. A paradigm shift in ecosystem restoration is needed that emphasizes traits and affected ecological processes similar to weeds. The repeated introduction of seed from native plants with weedy characteristics follows the propagule pressure and evolution of invasiveness hypotheses. In targeting areas with heavy weed populations, native plants could establish …

Essential Outcomes For Cop26, Pete Smith, Linda Beaumont, Carl J. Bernacchi, Maria Byrne, William Cheung, Richard T. Conant, Francesca Cotrufo, Xiaojuan Feng, Ivan Janssens, Hefin Jones, Miko U.F. Kirschbaum, Kazuhiko Kobayashi, Julie Laroche, Yiqi Luo, Andrew Mckechnie, Josep Penuelas, Shilong Piao, Sharon Robinson, Rowan F. Sage, David J. Sugget, Stephen J. Thackeray, Danielle Way, Stephen P. Long

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The UK Government is hosting COP26 in Glasgow between 31st October and 12th November 2021. It plans to make progress in four key areas which summarize as ‘coal, cars, cash and trees’ (Carbon Brief, 2021). The first two of these aims—to get agreement for the rapid phase out of coal, the most polluting of fossil fuels, and to ensure a rapid transition away for cars fuelled by fossil fuels—are very important, but are not directly related to the remit of Global Change Biology. The latter two aims—ensuring that the financial support of $100 billion per year promised in 2010 by …

Predicting Biochemical Acclimation Of Leaf Photosynthesis In Soybean Under In-Field Canopy Warming Using Hyperspectral Reflectance, Etsushi Kumagai, Charles H. Burroughs, Taylor L. Pederson, Christopher M. Montes, Bin Peng, Hyungsuk Kimm, Kaiyu Guan, Elizabeth A. Ainsworth, Carl J. Bernacchi

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Traditional gas exchange measurements are cumbersome, which makes it difficult to capture variation in biochemical parameters, namely the maximum rate of carboxylation measured at a reference temperature (Vcmax25) and the maximum electron transport at a reference temperature (Jmax25), in response to growth temperature over time from days to weeks. Hyperspectral reflectance provides reliable measures of Vcmax25 and Jmax25; however, the capability of this method to capture biochemical acclimations of the two parameters to high growth temperature over time has not been demonstrated. In this study, Vcmax25 and Jmax25 were measured over multiple growth stages during two growing seasons for field-grown …