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Crop Science : Just Published


Accepted, edited articles are published here after author proofing to provide rapid publication and better access to the newest research. Articles are compiled into issues at dl.sciencesocieties.org/publications/cs, which includes the complete archive.

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Lorenz, A.J., T.J. Gustafson, J.G. Coors, and N. de Leon. 2009. Breeding Maize for a Bioeconomy: A Literature Survey Examining Harvest Index and Stover Yield and Their Relationship to Grain Yield. Crop Sci. doi: 10.2135/cropsci2009.02.0086

Current issue: Crop Sci. 56(4)


    • Santosh Sharma and Marcelo J. Carena
      BRACE: A Method for High Throughput Maize Phenotyping of Root Traits for Short-Season Drought Tolerance

      There is a need to develop new maize (Zea mays L.) breeding methodologies for the easier screening of quantitative traits that are largely influenced by the environment. Molecular laboratories initially intended to work with these challenging and economically important traits but have targeted genetically simple traits instead, often not a challenge to breeders. Root systems are important components of drought tolerance in maize genotypes. Phenotyping maize root systems without destroying experimental plots, however, is challenging. (continued)

      Published: July 21, 2016

    • Ali Soltani, Marco Bello, Eninka Mndolwa, Stephan Schroder, Samira Mafi Moghaddam, Juan M. Osorno, Phillip N. Miklas and Phillip E. McClean
      Targeted Analysis of Dry Bean Growth Habit: Interrelationship among Architectural, Phenological, and Yield Components

      An ideotype breeding strategy to improve an economically important trait is achievable if subcomponent phenotypes most associated with the trait are targeted for selection. The success of this strategy in modern breeding history can be highlighted in dry bean (Phaseolus vulgaris L.), where an enhancement in dry bean production was facilitated in the last 25 yr by replacing Type III prostrate growth habit with Type II upright growth habit. This growth habit leads to disease avoidance and enables cost-effective management practices. To better understand the ideotype breeding trajectory in dry bean, and guarantee further improvements, we characterized 16 traits at three locations using a panel consisting of 122 genotypes with different growth habits. (continued)

      Published: August 18, 2016

    • Ahmad H. Sallam and Kevin P. Smith
      Genomic Selection Performs Similarly to Phenotypic Selection in Barley

      Genomic selection uses marker-based predictions to improve and accelerate the breeding process. Numerous studies have investigated the accuracy of genomic predictions; however, few studies have directly compared genomic and phenotypic selection. We compared genomic and phenotypic selection in five sets of selection candidates from a barley breeding program. In each set, about 96 breeding lines were genotyped with 1536 single nucleotide polymorphism (SNP) markers and phenotyped for yield, Fusarium head blight (FHB) severity, and deoxynivalenol (DON) concentration. (continued)

      Published: August 18, 2016

    • Matías de Felipe, José A. Gerde and José L. Rotundo
      Soybean Genetic Gain in Maturity Groups III to V in Argentina from 1980 to 2015

      Genetic progress is assessed to estimate its contribution to on-farm yield increases and to identify traits that have been improved over some period of time. Although Argentina is a major soybean [Glycine max (L.) Merr.] producer, there is limited information about genetic progress in this system. Argentinean soybean cultivars were developed from US commercial cultivars. Because the genetic base of US cultivars is narrow, it would be expected that genetic progress in Argentina to be slower than in the United States. (continued)

      Published: August 18, 2016

    • Moon-Sub Lee, A. Lane Rayburn and D. K. Lee
      Genesis and Identification of Octoploids Generated from Tetraploid Prairie Cordgrass

      Prairie cordgrass (Spartina pectinata Link) is a warm season (C4) perennial grass that could be a potential candidate for studying polyploidization and its effects on environmental adaptability. Polyploidy plays an important role in prairie cordgrass’s adaptation and distribution on different ecoregions in the North American Prairie. However, the genetic backgrounds of polyploidy prairie cordgrass distributed in the different edaphic regions are different. Thus, to extend our knowledge of the effect of polyploidy on environmental adaptation, it is necessary to have diverse ploidy levels of plants with a similar genetic background. (continued)

      Published: August 12, 2016

    • Chantal E. McCabe, Asheesh K. Singh, Leonor F. Leandro, Silvia R. Cianzio and Michelle A. Graham
      Identifying New Sources of Resistance to Brown Stem Rot in Soybean

      Brown stem rot (BSR), caused by the fungus Phialophora gregata f. sp. sojae (Allington & D.W. Chamberlain) W. (continued)

      Published: August 4, 2016

    • Anna K. Stasko, Damitha Wickramasinghe, Brittany J. Nauth, Bhupendra Acharya, Margaret L. Ellis, Christopher G. Taylor, Leah K. McHale and Anne E. Dorrance
      High-Density Mapping of Resistance QTL Toward Phytophthora sojae , Pythium irregulare , and Fusarium graminearum in the Same Soybean Population

      Phytophthora sojae Kaufm. and Gerd., Pythium irregulare Busiman, and Fusarium graminearum Schwabe [teleomorph: Gibberella zeae (Schwien.) Petch] are important pathogens of soybean [Glycine max (L.) Merr.] and are all capable of causing seed rot, damping-off, and root rot. The objective of this study was to identify quantitative trait loci (QTL) for resistance to Py. irregulare and to refine previously mapped QTL for resistance to P. (continued)

      Published: July 28, 2016

    • Jason G. Wallace, Xuecai Zhang, Yoseph Beyene, Kassa Semagn, Michael Olsen, Boddupalli M. Prasanna and Edward S. Buckler
      Genome-wide Association for Plant Height and Flowering Time across 15 Tropical Maize Populations under Managed Drought Stress and Well-Watered Conditions in Sub-Saharan Africa

      Genotyping breeding materials is now relatively inexpensive but phenotyping costs have remained the same. One method to increase gene mapping power is to use genome-wide genetic markers to combine existing phenotype data for multiple populations into a unified analysis. We combined data from 15 biparental populations of maize (Zea mays L.) (>2500 individual lines) developed under the Water-Efficient Maize for Africa project to perform genome-wide association analysis. Each population was phenotyped in multilocation trials under water-stressed and well-watered environments and genotyped via genotyping-by-sequencing. (continued)

      Published: July 28, 2016

    • Sovetgul Asekova, Krishnanand P. Kulkarni, Minsu Kim, Jeong-Hwa Kim, Jong Tae Song, J. Grover Shannon and Jeong-Dong Lee
      Novel Quantitative Trait Loci for Forage Quality Traits in a Cross between PI 483463 and ‘Hutcheson’ in Soybean

      Soybean [Glycine max (L.) Merr.] is one of the most important forage crops in the world. This study aimed to map quantitative trait loci (QTL) for crude protein (CP), crude fat (CF), neutral detergent fiber (NDF) and acid detergent fiber (ADF) in soybean. A set of 188 recombinant inbred lines (RILs) derived from a cross between PI 483463 and ‘Hutcheson’ were grown for three consecutive years. Plants of each RIL were harvested at the R6 stage and quality traits were measured using near-infrared reflectance spectroscopy (NIRS). (continued)

      Published: July 28, 2016

    • Nilwala S. Abeysekara, Rashelle L. Matthiesen, Silvia R. Cianzio, Madan K. Bhattacharyya and Alison E. Robertson
      Novel Sources of Partial Resistance against Phytophthora sojae in Soybean PI 399036

      With the rapid emergence of novel pathogen pathotypes, durable sources of resistance against Phytophthora sojae in soybean [Glycine max (L.) Merrill] are needed to manage Phytopthora stem and root rot (PRR). This study used an inoculum source composed of multiple isolates of the pathogen to characterize partial resistance (PR) to P. sojae in plant introduction (PI) 399036. Two recombinant inbred line (RIL) F5:7 populations developed by crossing PI 399036 (high PR), with two germplasm lines (low PR), AR2 (AX20925) and AR3 (AX20931), were screened. (continued)

      Published: July 28, 2016

    • Luis Inostroza, Hernán Acuña, Patricio Munoz, Catalina Vásquez, Joel Ibáñez, Gerardo Tapia, María Teresa Pino and Hernán Aguilera
      Using Aerial Images and Canopy Spectral Reflectance for High-Throughput Phenotyping of White Clover

      Plant breeders are demanding high-throughput phenotyping methodologies to complement the abundant genomic information currently available. Remote-sensing technologies offer new tools for high-throughput phenotyping in field conditions, and many remote sensors have shown high capacity for describing plant physiological behavior. The objective of this study was to evaluate the genotypic relationship between high-throughput phenotyping based on image analysis and canopy reflectance estimated traits and dry matter (DM) production, the most important trait in forage species. An experiment of a white clover (Trifolium reens L.) association-mapping population was established in three locations. (continued)

      Published: July 28, 2016

    • Joshua A. Macke, Martin O. Bohn, Kent D. Rausch and Rita H. Mumm
      Genetic Factors Underlying Dry-Milling Efficiency and Flaking-Grit Yield Examined in US Maize Germplasm

      A small but important proportion of US maize (Zea mays L.) grain is channeled to create breakfast cereals and other food products; yet, little focus has been devoted to genetic improvement of corn hybrids to meet needs of dry millers and other end users in the cereal pipeline. This study was designed to evaluate a broad range of US maize germplasm for key dry-milling traits: dry-milling efficiency (DME), the proportion of flaking grits produced from dry-milled maize grain, and flaking-grit yield (FGY), the amount of flaking grits produced per unit land. Genetic parameters for DME and FGY were characterized based on grain produced over 3 yr, and the associations between dry-milling, agronomic, ear, and kernel traits were assessed. Means for DME among experimental hybrids ranged from 24.0 to 36.0%. (continued)

      Published: July 28, 2016

    • M. Gabriela Borgognone, David G. Butler, Francis C. Ogbonnaya and M. Fernanda Dreccer
      Molecular Marker Information in the Analysis of Multi-Environment Trials Helps Differentiate Superior Genotypes from Promising Parents

      The statistical analysis of multi-environment trial data aims to provide reliable and accurate predictions of genotype performance across the target environments and information on specific performance from the interaction of genotypes with the environments. Genetic gain can be achieved faster when selections are based on predictions from a model that accounts for the relationships among genotypes rather than from a model that assumes unrelated genotypes. Yield and plant height data from 37 international wheat trials were analyzed using a linear mixed model that accounted for relationships among the genotypes via a genomic relationship matrix derived from 2487 polymorphic DArT molecular markers for 197 genotypes. The elements of this matrix reflect the actual proportion of the parts of the genome surveyed that is identical by state between pairs of individuals, and including it into the model resulted in generally lower average prediction error variances of individual trials in the analyses. (continued)

      Published: July 28, 2016

    • Jessica K. Cooper, John A. Stromberger, Craig F. Morris, Guihua Bai and Scott D. Haley
      End-Use Quality and Agronomic Characteristics Associated with the Glu-B1al High-Molecular-Weight Glutenin Allele in U.S. Hard Winter Wheat

      High-molecular-weight glutenin subunits (HMW-GS) conferred by alleles at the , Glu-B1, and Glu-D1 loci confer unique end-use quality properties for wheat (Triticum aestivum L.). The Glu-B1al allele at the Glu-B1 locus has not been widely used for cultivar development in the U.S. hard winter wheat region. We evaluated four groups of near-isogenic lines (NILs) with different combinations of alleles at Glu-B1, allele b (encoding subunits Bx7 + By8) or a1 (subunits Bx7OE + By8), and at Glu-D1, allele a (subunits Dx2 + Dy12) or d (subunits Dx5 + Dy10), to assess direct and indirect effects attributed to the Glu-B1al allele. (continued)

      Published: July 28, 2016

    • Joseph E. Knoll and William F. Anderson
      Yield Components in Hybrid versus Inbred Sweet Sorghum

      Sweet sorghum [Sorghum bicolor (L.) Moench] should be an ideal biofuel crop for the southeastern United States, but the current cultivars are all pure lines, which limits the quantity of seed that can be produced, and this seed cannot be mechanically harvested. Hybrid seed can be easily produced on short-statured plants, but less is known about other advantages of hybrid sweet sorghum over inbred cultivars. Heterosis in this crop has not been extensively studied in this region. Three female lines and 19 male lines were crossed in a factorial mating design (Design II) experiment. (continued)

      Published: July 28, 2016

    • Ki-Seung Kim, Joshua D. Anderson, Mark A. Newell, Sarah M. Grogan, Patrick F. Byrne, P. Stephen Baenziger and Twain J. Butler
      Genetic Diversity of Great Plains Hard Winter Wheat Germplasm for Forage

      Wheat (Triticum aestivum L.) has been widely grown for winter forage production across the world. However, improvement of forage yield and nutritive characteristics has not been a major goal of wheat breeding programs, and little is known about genetic diversity in the traits of winter wheat germplasm. A set of 299 hard winter wheat germplasm from the Great Plains was evaluated during two growing seasons in Oklahoma and 15 forage-related traits were evaluated. There were significant (P < 0.0001) genetic variations in all the traits but effects of environment and germplasm × environment interaction were significant for seven and eight traits, respectively. (continued)

      Published: July 14, 2016

    • P. Janila, Surendra S. Manohar, Nagesh Patne, Murali T. Variath and S.N. Nigam
      Genotype × Environment Interactions for Oil Content in Peanut and Stable High-Oil-Yielding Sources

      Peanut (Arachis hypogaea L.) genotypes with superior and stable agronomic performance and high oil content were identified from testing of 160 advanced breeding lines over six seasons. The study revealed significant genotype and genotype × environment (G × E) interaction determining oil and protein content; shelling outturn; and pod, kernel, and oil yield in peanut. The variability among genotypes was high across the environments for pod yield (546–7382 kg ha−1), oil yield (301–2742 kg ha−1), oil content (37–60%), 100-seed weight (21–127 g), and protein content (19–31%). The GGE biplot technique revealed that ICGV 05155 is a stable genotype for oil yield with an average oil yield of 1886 kg ha−1. (continued)

      Published: July 14, 2016

    • Caijie Wang, Tingting Wu, Shi Sun, Ran Xu, Jianjun Ren, Cunxiang Wu, Bingjun Jiang, Wensheng Hou and Tianfu Han
      Seventy-five Years of Improvement of Yield and Agronomic Traits of Soybean Cultivars Released in the Yellow-Huai-Hai River Valley

      Yellow-Huai-Hai River Valley (YHH) in China has a long history of soybean [Glycine max (L.) Merr.] breeding. The genetic improvement of yield and agronomic traits of soybean cultivars due to breeding is rarely documented. The objectives were to analyze the trend of changes on widely-grown soybean cultivars in this region. Twenty-five soybean cultivars released over the period from 1929 until 2004 were selected. (continued)

      Published: July 14, 2016

    • Georgia C. Eizenga, Jeremy D. Edwards, Kathleen M. Yeater, Susan R. McCouch and Anna M. McClung
      Transgressive Variation for Yield Components Measured throughout the Growth Cycle of Jefferson Rice ( Oryza sativa ) × O. rufipogon Introgression Lines

      Previous studies demonstrated that alleles introduced into elite rice (Oryza sativa L.) cultivars from the wild, ancestral species Oryza rufipogon Griff. enhanced yield as a result of transgressive variation. A study was conducted to unveil the phenological and agronomic mechanisms that underlie increased yields in introgression lines (ILs) developed through backcrossing an O. rufipogon accession [International Rice Germplasm Collection (IRGC) 105491] with the recurrent parent, ‘Jefferson’, a U.S. (continued)

      Published: July 14, 2016

    • B. Badu-Apraku, C.G. Yallou, H. Alidu, A.O. Talabi, I.C. Akaogu, B. Annor and A. Adeoti
      Genetic Improvement of Extra-Early Maize Cultivars for Grain Yield and Striga Resistance during Three Breeding Eras

      Maize (Zea mays L.), a food security crop in West Africa (WA) is threatened by Striga hermonthica (Del.) Benth. infestation. A study was conducted at five locations in WA for 2 yr to determine genetic gains in grain yield of 56 extra-early maturing cultivars developed during three breeding eras, 1995 to 2000 (Era 1), 2001 to 2006 (Era 2), and 2007 to 2012 (Era 3) under Striga-infested and Striga-free conditions. Yield ranged from 1827 kg ha−1 for Era 1 cultivars to 2292 kg ha−1 for Era 3 cultivars under Striga infestation with average rate of increase in grain yield of 42 kg ha−1 yr−1 corresponding to 2.56% annual genetic gain. (continued)

      Published: July 14, 2016

    • Ryan D. Huffman, Jode W. Edwards, Linda M. Pollak and M. Paul Scott
      Interaction of Genetic Mechanisms Regulating Methionine Concentration in Maize Grain

      Methionine is a limiting amino acid in poultry diets, so methionine supplementation is typically required to meet nutritional demands. Maize (Zea mays L.) varieties with increased methionine levels have been developed using three different approaches: (i) increased levels of the methionine-rich 10-kDa zein, (ii) disruption of protein deposition using the floury-2 allele, and (iii) recurrent selection. The goal of this study was to characterize the interactions of these three mechanisms for increasing methionine to develop optimal breeding strategies for this limiting amino acid. A complete diallel mating design was used to produce all possible hybrid combinations, which were analyzed by Griffing’s experimental Method 3, Model 1. (continued)

      Published: July 14, 2016

    • Heathcliffe Riday
      Northern U.S.–Adapted 2,4-D-Resistant Red Clover

      2,4-Dichlorophenoxyacetic acid (2,4-D)–resistant red clover (Trifolium pratense L.) varieties would offer producers more weed control options, particularly in mixed grass–red clover pastures. In the 1980s, work was initiated in Florida to select for 2,4-D-tolerant red clover. However, this Florida germplasm was not adapted to cool, humid regions in the northern United States. A greenhouse selection program was initiated to develop 2,4-D-resistant germplasm (WI-2,4D12) that is more adapted to the northern United States. (continued)

      Published: July 14, 2016

    • Valerio Hoyos-Villegas, Qijian Song, Evan M. Wright, Stephen E. Beebe and James D. Kelly
      Joint Linkage QTL Mapping for Yield and Agronomic Traits in a Composite Map of Three Common Bean RIL Populations

      Bean (Phaseolus vulgaris L.) production is challenged by many limitations with drought being among the top causes of crop failure worldwide. In this study, we constructed three small-red-seeded bean recombinant inbred line (RIL) mapping populations (S48M, S94M, and S95M) with a common parent (‘Merlot’) and performed joint interval mapping analysis as a small nested association mapping (NAM) population for agronomic traits and performance under rainfed conditions in Michigan. The objective was to identify novel sources of improved performance and genomic regions associated with desirable traits under rainfed and water-sufficient conditions in small-red bean breeding materials adapted to temperate zones. A composite linkage map was constructed using single-nucleotide polymorphism (SNP) markers from the three populations and resulted in an improved version of the individual linkage maps shown by a greater genome span covered in the composite map (909 cM). (continued)

      Published: July 14, 2016

    • J. Jesus Cerón-Rojas, José Crossa, Fernando H. Toledo and Jaime Sahagún-Castellanos
      A Predetermined Proportional Gains Eigen Selection Index Method

      The most general linear phenotypic selection index (PSI) is the predetermined proportional gains phenotypic selection index (PPG-PSI) that allows imposing restrictions on the trait expected genetic gain values to make some traits change their mean values based on a predetermined level, while the rest of the traits remain without restrictions. However, due to the increasing number of restricted traits: (i) PPG-PSI accuracy decreases; (ii) the proportional constant associated with this index can be negative, in which case, its results have no meaning in practice; and (iii) the PPG-PSI can shift the population means in the opposite direction to the predetermined desired direction. Based on the eigen selection index method (ESIM), we propose a PPG-ESIM that does not require a proportional constant, and due to the properties associated with eigen analysis, it is possible to use the theory of similar matrices to change the direction of the eigenvector values without affecting PPG-ESIM accuracy, which helps to eliminate the problem indicated in the third point above, associated with the standard PPG-PSI. The PPG-ESIM uses the first eigenvector as its vector of coefficients, and the first eigenvalue in the selection response. (continued)

      Published: June 29, 2016

    • Zachary G. Jones and Major M. Goodman
      Susceptibility of Dent-Sterile Popcorn to the Ga1-m Gametophyte Factor

      The Ga1-s allele is the foundation of dent-sterile popcorn (Zea mays L. var. everta), where it is used as a genetic barrier to prevent pollen contamination, but its known genetic susceptibility to another allele at the same locus is problematic for the sustainability of Ga1-s popcorn. The Ga1-m allele overcomes the pollen barrier imparted by Ga1-s, opening any system using it to potential contamination. (continued)

      Published: June 24, 2016

    • Amritpal Singh, Aaron P. Andersen, Tamra A. Jackson-Ziems and Aaron J. Lorenz
      Mapping Quantitative Trait Loci for Resistance to Goss’s Bacterial Wilt and Leaf Blight in North American Maize by Joint Linkage Analysis

      Goss’s wilt and leaf blight is a bacterial disease of maize (Zea mays L.) caused by the Gram-positive bacterium Clavibacter michiganensis subsp. nebraskensis. Goss’s wilt has re-emerged as an important disease in the western United States and is spreading to other areas. Although the reasons for this re-emergence are not completely known, it is important to understand the genetic basis of resistance to Goss’s wilt. (continued)

      Published: June 24, 2016

    • Brian D. De Vries and William F. Tracy
      Characterization of Endosperm Carbohydrates in isa2–339 Maize and Interactions with su1-ref

      Selection for genetic modifiers of starch and sugar accumulation in sugary1-ref (su1-ref) maize (Zea mays L.) has led to the improvement of flavor characteristics in su1 sweet corn hybrids. The Su1 gene encodes a starch debranching enzyme that when defective causes large quantities of water-soluble polysaccharides (WSP) to be produced in maize endosperm tissue. Another gene in maize, Isoamylase2 (Isa2), produces a starch debranching enzyme known to interact with the wild-type SU1 protein in developing maize endosperm. Experiments were conducted to determine if a mutant of the Isa2 gene significantly modifies carbohydrate composition in su1-ref inbreds and therefore is potentially useful for modifying flavor characteristics of su1 sweet corn. (continued)

      Published: June 24, 2016

    • Hans-Peter Piepho, Mian Faisal Nazir, Maqsood Qamar, Atiq-ur-Rehman Rattu, Riaz-ud-Din, Manzoor Hussain, Gulzar Ahmad, Fazal-e-Subhan, Javed Ahmad, Abdullah, Karim Bux Laghari, Imad Ali Vistro, M. Sharif Kakar, Mehboob Ali Sial and Muhammad Imtiaz
      Stability Analysis for a Countrywide Series of Wheat Trials in Pakistan

      In Pakistan, wheat (Triticum aestivum L.) varieties undergo intensive yield testing within the National Uniform Wheat Yield Trials (NUWYT) before recommendations are made to farmers. The trialing network extends across 12 different agroecological zones defined for the whole of the country. In this paper, we consider the analysis of data from this trial system over 2 yr and 34 locations. For each of the 16 varieties, variances of genotype × location (G × L) and genotype × location × year (G × L × Y) interactions were estimated to assess stability. (continued)

      Published: June 17, 2016

    • Qingfeng Li, Yuqing Lu, Cuili Pan, Jinpeng Zhang, Weihua Liu, Xinming Yang, Xiuquan Li, Yajun Xi and Lihui Li
      Characterization of a Novel Wheat– Agropyron cristatum 2P Disomic Addition Line with Powdery Mildew Resistance

      Agropyron cristatum (L.) Gaertn. (2n = 4x = 28; genomes PPPP) is one of the wild species closely related to cultivated wheat (Triticum aestivum L.), which possesses a number of superior agronomic traits and thus represents a valuable resource for wheat improvement. Development of wheat–A. cristatum addition lines is usually considered to be the first step in transferring desirable alien genes into common wheat from A. (continued)

      Published: June 17, 2016

    • Santosh G. Rajput and Dipak K. Santra
      Evaluation of Genetic Diversity of Proso Millet Germplasm Available in the United States using Simple-Sequence Repeat Markers

      Proso millet (Panicum miliaceum L.) is the best rotational crop in most dryland production areas in the semiarid US High Plains because of the highest water use efficiency among all cereal crops and short growing season. In the United States, it is used for birdseed, but it is used mostly for human consumption in Asia and Europe. Genomic resources and genetic research of this crop are limited. There is no report of molecular marker-based genetic diversity analysis of the US germplasm, which is important for its genetic improvement. (continued)

      Published: June 17, 2016

    • Neil O. Anderson, Tereza Kávová, Daša Bastlová, Vladislav Čurn, Barbora Kubátová, Keith R. Edwards, Vojtěch Januš and Jan Květ
      Phenotypic and Genotypic Variation in Czech Forage, Ornamental and Wild Populations of Reed Canarygrass

      Reed canarygrass (Phalaris arundinacea L.) is native to Europe and North America, being invasive in the latter since the 20th century. No phenotypic differences have been found in plants from each continent; genetic analyses have been controversial—implicating or exonerating forage/ornamental cultivars for spread throughout North America. Within central Europe, particularly the Czech Republic, it is unknown whether wild genotypes and cultivars are genetically and phenotypically similar. The objectives of this study were to compare commercial forage and ornamental cultivars sold within the Czech Republic with wild genotypes from native populations along major Czech rivers and characterize the extent of phenotypic and genetic variation. (continued)

      Published: June 17, 2016

    • H. Frederick W. Rattunde, Sebastian Michel, Willmar L. Leiser, Hans-Peter Piepho, Chiaka Diallo, Kirsten vom Brocke, Bocar Diallo, Bettina I. G. Haussmann and Eva Weltzien
      Farmer Participatory Early-Generation Yield Testing of Sorghum in West Africa: Possibilities to Optimize Genetic Gains for Yield in Farmers’ Fields

      The effectiveness of on-farm and/or on-station early generation yield testing was examined to maximize the genetic gains for sorghum yield under smallholder famer production conditions in West Africa. On-farm first-stage yield trials (augmented design, 150 genotypes with subsets of 50 genotypes tested per farmer) and second-stage yield trials (replicated α-lattice design, 21 test genotypes) were conducted, as well as on-station α-lattice first- and second-stage trials under contrasting phosphorous conditions. On-farm testing was effective, with yield showing significant genetic variance and acceptable heritabilities (0.56 in first- and 0.61 to 0.83 in second-stage trials). Predicted genetic gains from on-station yield trials were always less than from direct testing on-farm, although on-station trials under low-phosphorus and combined over multiple environments improved selection efficiencies. (continued)

      Published: June 17, 2016

    • Wei Luo, Jian Ma, Xiao-Hong Zhou, Min Sun, Xing-Chen Kong, Yu-Ming Wei, Yun-Feng Jiang, Peng-Fei Qi, Qian-Tao Jiang, Ya-Xi Liu, Yuan-Ying Peng, Guo-Yue Chen, You-Liang Zheng, Chunji Liu and Xiu-Jin Lan
      Identification of Quantitative Trait Loci Controlling Agronomic Traits Indicates Breeding Potential of Tibetan Semiwild Wheat ( Triticum aestivum ssp. tibetanum )

      Tibetan semiwild wheat (Triticum aestivum ssp. tibetanum Shao) is a primitive hexaploid wheat resource found in Tibet. It is characterized by tolerance to nutrition deficiency and strong seed dormancy and has potential to be useful in wheat breeding programs. To tap the advantages of Tibetan semiwild wheat in wheat breeding, we investigated nine agronomic traits including heading date (HD), anthesis date (AD), plant height (PHT), tiller number (TN), spike length (SL), spikelet number per spike (SNS), spikelet density (DS), grain weight per spike (GWS), and 1000-grain weight (TGW) in 186 recombinant inbred lines from a cross between Tibetan semiwild wheat ‘Q1028’ and common wheat ‘Zhengmai 9023’ (ZM 9023) across three growing seasons. (continued)

      Published: June 17, 2016

    • R. Ding and A.M. Missaoui
      Phenotyping Summer Dormancy in Tall Fescue: Establishment of a Surrogate Phenotype and a Dormancy Rating System in Humid Environments

      Tall fescue [Lolium arundinaceum (Schreb.) Darbysh] is a cool-season perennial grass with two major types of germplasm, Continental and Mediterranean. Most Mediterranean germplasm exhibit summer dormancy even when conditions are favorable for growth. Phenotyping summer dormancy in the field is difficult and costly. The objectives of this study are to develop a low-cost surrogate phenotyping approach for summer dormancy. (continued)

      Published: June 17, 2016

    • Habibur Rahman, Rick A. Bennett and Rong-Cai Yang
      Patterns of Heterosis in Three Distinct Inbred Populations of Spring Brassica napus Canola

      Allelic diversity of the allied species of Brassica napus L. as well as of the winter form of this species has been demonstrated to be related with increasing productivity of hybrid spring B. napus cultivars. To compare potential value of the different gene pools of Brassica species three spring B. (continued)

      Published: June 14, 2016

    • Brian D. De Vries, Stacie L. Shuler and William F. Tracy
      Endosperm Carbohydrates in Pseudostarchy and Extreme-sugary Maize Inbreds During Kernel Development

      Evaluation of endosperm carbohydrates kernels of pseudostarchy, su1-ref, and wild type inbreds will give us an understanding of pseudostarchy composition relative to wild type and should inform us on the underlying biochemistry of starch synthesis. A set of seven maize inbreds, fixed for the su1-ref allele, were developed from two divergently selected maize populations. Three of these inbreds (pse) have a pseudostarchy kernel phenotype and four (esu) have a typical sugary kernel appearance. These seven inbreds were grown in two environments each with two field replications with the inbreds Ia453 su1-ref and Ia453 Su1 (wild type). (continued)

      Published: May 27, 2016

    • B.T. Campbell, K.D. Chapman, D. Sturtevant, C. Kennedy, P. Horn, P.W. Chee, E. Lubbers, W.R. Meredith, J. Johnson, D. Fraser and D.C. Jones
      Genetic Analysis of Cottonseed Protein and Oil in a Diverse Cotton Germplasm

      Historically, the primary objective of cotton (Gossypium hirsutum L.) breeding programs was to improve the quantity and quality of cotton fiber. Because of the added value of cottonseed and its many uses, including a feed and human food source, there is interest in developing cotton breeding programs that focus improvement efforts simultaneously on cotton fiber and seed. Genetic analysis of cottonseed traits, such as protein and oil, is a prerequisite to building new joint fiber and seed cotton breeding programs. In this study, we conducted a genetic analysis of a diverse set of elite upland cotton germplasm for cottonseed protein and oil. (continued)

      Published: June 14, 2016

    • Xing-Ming Fan, Xing-Fu Yin, Yu-Dong Zhang, Ya-Qi Bi, Li Liu, Hong-Mei Chen and Manjit S. Kang
      Combining Ability Estimation for Grain Yield of Maize Exotic Germplasm Using Testers from Three Heterotic Groups

      Combining ability estimates of lines to be used in breeding are useful for maize (Zea mays L.) breeders. The objectives of this study were to (i) evaluate combining ability of 25 improved exotic germplasm using different numbers of testers (1 to 3) from Suwan1, Reid, and non-Reid heterotic groups; (ii) study differences in combining ability estimates obtained with different number of testers from the same vs. different heterotic groups; and (iii) determine the appropriate segregating (‘S’) generation in which line selection should be done to obtain stable general combining ability (GCA) estimates of lines. The results showed that three testers (one from each of the three heterotic groups) were economically best for estimating GCA effects of lines, and if a tester from one of the three heterotic groups was missed, GCA estimates for some lines were biased when compared with GCA estimates with testers from all three heterotic groups. (continued)

      Published: June 14, 2016

    • Diego Jarquín, Sergio Pérez-Elizalde, Juan Burgueño and José Crossa
      A Hierarchical Bayesian Estimation Model for Multienvironment Plant Breeding Trials in Successive Years

      In agriculture and plant breeding, multienvironment trials over multiple years are conducted to evaluate and predict genotypic performance under different environmental conditions and to analyze, study, and interpret genotype × environment interaction (G × E). In this study, we propose a hierarchical Bayesian formulation of a linear–bilinear model, where the conditional conjugate prior for the bilinear (multiplicative) G × E term is the matrix von Mises–Fisher (mVMF) distribution (with environments and sites defined as synonymous). A hierarchical normal structure is assumed for linear effects of sites, and priors for precision parameters are assumed to follow gamma distributions. Bivariate highest posterior density (HPD) regions for the posterior multiplicative components of the interaction are shown within the usual biplots. (continued)

      Published: February 12, 2016


    • Moriah Massafaro, Addie Thompson, Mitch Tuinstra and Clifford F. Weil
      Mapping the Increased Protein Digestibility Trait in the High-Lysine Sorghum Mutant P721Q

      Sorghum [Sorghum bicolor (L.) Moench] is a dietary staple for >500 million people in over 30 countries of the semiarid tropics. Unlike other major cereals, proteins in sorghum grain become much less digestible after wet cooking. P721Q is a high-lysine sorghum mutant that exhibits a three- to fourfold increase in protein digestibility after cooking as compared with other sorghum cultivars. While its increased lysine content has been traced to decreased levels of a kafirin storage protein, the goal of this study was to identify the genetic determinant of the increased digestibility. (continued)

      Published: July 14, 2016


    • Haile Tewolde, Michael R. McLaughlin, Thomas R. Way and Johnie N. Jenkins
      Optimum Poultry Litter Rates for Maximum Profit versus Yield in Cotton Production

      Cotton (Gossypium hirsutum L.) lint yield responds well to increasing rates of poultry litter fertilization, but little is known of how optimum rates for yield compare with optimum rates for profit. The objectives of this study were to analyze cotton lint yield response to poultry litter application rates, determine and compare rates that maximize lint yield (PLy) vs. profit (PLp), and identify a practical approach for estimating PLp. Cotton planted on two farms that used conventional and no-tillage systems were fertilized with seven target rates of litter from 0 to 13.5 Mg ha−1 or with a farm standard treatment receiving synthetic fertilizers (Std). (continued)

      Published: August 18, 2016

    • Fei Deng, Li Wang, Xiu-Feng Mei, Shu-Xian Li, Shi-Lin Pu and Wan-Jun Ren
      Polyaspartate Urea and Nitrogen Management Affect Nonstructural Carbohydrates and Yield of Rice

      In rice (Oryza sativa L.), nonstructural carbohydrates (NSC) play an important role in grain yield. To investigate the effects of urea type (polyaspartate urea versus conventional urea) and N management method (farmer’s fertilizer practice and optimized N management) on NSC accumulation and remobilization in rice, field experiments were conducted in Wenjiang, China, in 2014 and 2015. Grain yield, effective panicles, and total number of spikelets were positively related to NSC accumulation in aboveground parts and remobilization of stored NSC (RSN) in the stem plus sheath from 20 d after heading to maturity. Polyaspartate urea, in place of conventional urea, increased NSC accumulation in the leaf lamina and the stem plus sheath at the heading stage and promoted RSN in the stem plus sheath from 20 d after heading to maturity, improving grain yield and total aboveground biomass. (continued)

      Published: August 18, 2016

    • Jianguo Man, Zhenwen Yu, Yongli Zhang, Yu Shi and Liqiu Wang
      Water and Nitrogen Use of Winter Wheat under Different Supplemental Irrigation Regimes

      Winter wheat (Triticum aestivum L.) production in the Huang-Huai-Hai plain of China has been threatened by drought. This study was conducted to determine the water and N use of wheat under quantifying irrigation (W1, 60 mm of irrigation each at jointing and anthesis) and supplemental irrigation, determined by measuring the water content in the 0- to 20-cm (W2), 0- to 40-cm (W3), and 0- to 60-cm (W4) soil layers. The highest grain yields of 9177 kg ha−1 in 2012 to 2013 and 9460 kg ha−1 in 2013 to 2014 were obtained in W3, which exhibited greater soil water consumption in the 60- to 140-cm soil layers. Soil nitrate N uptake in the 40- to 160-cm soil layers was higher than in W1, W2, and W4 treatments. (continued)

      Published: August 18, 2016

    • Yunfei Jiang, Jili Li and Claude D. Caldwell
      Glucosinolate Content of Camelina Genotypes as Affected by Applied Nitrogen and Sulphur

      Camelina [Camelina sativa (L.) Crantz] is an alternative oil crop that has potential in aquaculture and food production. However, glucosinolates (GSs) in camelina seed and meal constrain their application in human and animal consumption. Glucosinolates are plant secondary metabolites commonly found in the Brassicaceae family. The aims of this study were to determine whether nitrogen (N) alone or in combination with sulphur (S) application affected GS concentration in camelina seeds, as well as whether different genotypes differed in GS concentrations. (continued)

      Published: August 4, 2016

    • Virginia Nichols, Fernando Miguez, Thomas Sauer and Ranae Dietzel
      Maize and Prairie Root Contributions to Soil CO 2 Emissions in the Field

      Increasing soil carbon content via agricultural practices not only enhances the production potential of the land, but also counteracts rising atmospheric CO2 levels. When predicting production systems’ effects on soil carbon, quantifying CO2 efflux derived from live roots is of particular importance as it is a through-flux and does not signify depletion of soil carbon. This field study aimed to measure and compare soil CO2 emissions derived from roots in annual and perennial agroecosystems. We used periodic 48-hour shading over two growing seasons to estimate root growth-derived CO2 in continuously grown maize (CC) with grain and 50% stover harvested each year, unfertilized reconstructed tallgrass prairie (P), and the same prairie grown with spring nitrogen fertilization (PF), both which had biomass harvested post-frost. (continued)

      Published: July 28, 2016

    • Yared Assefa, P. V. Vara Prasad, Paul Carter, Mark Hinds, Gaurav Bhalla, Ryan Schon, Mark Jeschke, Steve Paszkiewicz and Ignacio A. Ciampitti
      Yield Responses to Planting Density for US Modern Corn Hybrids: A Synthesis-Analysis

      Identifying an optimal plant density is a critical management decision for corn (Zea mays L.) production. The main objectives of this study were to: (i) investigate the grain yield responses to plant density (yield–density relationship), (ii) identify best fitted yield–density response curves, and (iii) explore genotype (G) × environment (E) interaction effect on yield–density response models. Analysis was conducted on meta-data (124,374 observations) gathered from 22 US states and 2 Canadian provinces, diverse sites (E), for years from 2000–2014 on multiple hybrids (G). Yield data were further grouped into four yield environments (low [LY], <7 Mg ha−1; medium [MY], 7–10 Mg ha−1; high [HY], 10–13 Mg ha−1; and very high [VHY], >13 Mg ha−1 yielding groups). (continued)

      Published: July 28, 2016

    • Liu Shengnan, Song Xiaoling, Hu Yanhua, Dai Weiming and Qiang Sheng
      Fitness of Hybrids between Two Types of Transgenic Rice and Six Japonica and Indica Weed Rice Accessions

      Studies of hybrid fitness can help in evaluating the potential introgression of a transgene from transgenic rice (Oryza sativa L.) to weedy rice. The objective of this study was to assess the composite fitness of intra- (within the same subspecies either indica or japonica) and inter- (between individuals of different subspecies) hybrids between two transgenic glufosinate-resistant rice lines and six weedy rice accessions in the field. Compared with their weedy rice counterparts, intrahybrids may be similar or greater, and the interhybrids may be lower, similar, or greater in fitness. Using japonica transgenic rice Y0003 as male progenitor, composite fitness of intrahybrids increased over generations, while that of interhybrids kept variable over generations. (continued)

      Published: July 28, 2016

    • K. Ann Bybee-Finley, Steven B. Mirsky and Matthew R. Ryan
      Functional Diversity in Summer Annual Grass and Legume Intercrops in the Northeastern United States

      A warm-season annual intercropping experiment was conducted across the northeastern United States with four trials in 2013 and five trials in 2014 with four crop species selected based on differences in stature and N acquisition traits: (i) pearl millet [Pennisetum glaucum (L.) R. Br.], (ii) sorghum sudangrass [Sorghum bicolor (L.) Moench × S. sudanense (Piper) Stapf], (iii) cowpea [Vigna unguiculata (L.) Walp], and (iv) sunn hemp (Crotalaria juncea L.). Crops were seeded in monoculture and in three- and four-species mixtures using a replacement design where monoculture seeding rates were divided by the number of species in the intercrop. (continued)

      Published: June 24, 2016

    • Jeremy J. Milander, Zeljko Jukic, Stephen C. Mason, Tomie Glausha and Zaher Kmail
      Plant Population Influence on Maize Yield Components in Croatia and Nebraska

      Analysis of yield components to address inconsistent maize (Zea mays L.) grain yields across plant populations is limited in Europe and the United States. The research objectives were to compare maize yield components at low and high plant populations in eastern Nebraska and central Croatia using path analysis to better understand maize grain yield determination with changing plant population and determine relative importance among maize primary and secondary yield components. Research was conducted by planting three maize hybrids at 65,000 plants ha−1 to 105,000 plants ha−1 in 2012 and 2013 at Zagreb, Croatia, and Mead, NE. Grain yield, ears per square meter, rows per ear, ear circumference, kernels per ear, kernels per row, ear length, and kernel weight were determined. (continued)

      Published: June 24, 2016

    • Lewis H. Ziska, Jinyoung Yang, Martha B. Tomecek and Paul J. Beggs
      Cultivar-Specific Changes in Peanut Yield, Biomass, and Allergenicity in Response to Elevated Atmospheric Carbon Dioxide Concentration

      Intraspecific variation in response to rising atmospheric carbon dioxide concentration [CO2] could be used as a means to begin selection for improved quantitative or qualitative characteristics for a given crop. Peanut (Arachis hypogaea L.) is a leguminous crop of global importance; however multiyear field assessments of intraspecific variation in yield or seed quality in regard to rising atmospheric [CO2] are scarce. In the current study, we examined the seed yield, above-ground biomass, and concentration of a seed storage protein and primary allergen (Ara h 1) for two peanut cultivars with distinct morphologies, ‘Virginia Jumbo’ and ‘Georgia Green’, grown in open-top field chambers at ambient or ambient + 250 µmol mol−1 [CO2] for a 2-yr period. Significant differences in cultivar, [CO2], and cultivar × [CO2] were observed for above-ground biomass and seed (peanut) yield, with Virginia Jumbo showing a consistently greater increase relative to Georgia Green in response to elevated [CO2]. (continued)

      Published: June 17, 2016


    • Florencia Poeta, Lucas Borrás and José L. Rotundo
      Variation in Seed Protein Concentration and Seed Size Affects Soybean Crop Growth and Development

      Developing high protein (HP) cultivars is often precluded by the inverse relationship between protein and yield. We hypothesized that attaining HP concentration based on contrasting seed size impacts crop growth and development differently. We screened 97 soybean genotypes and found lines with HP concentration (∼450 g kg−1) associated with (i) increased protein content (mg seed−1) in large seed genotypes, and (ii) reduced oil and carbohydrate contents in small seed ones. Then, we evaluated different growth traits in a subset of three HP large and three HP small seed genotypes, as well as in three high-yielding genotypes with average seed size and protein concentration. (continued)

      Published: August 18, 2016

    • Randy Wells, David P.J. Eickholt, Ramsey Lewis, Matthew C. Vann and Loren R. Fisher
      Heat Unit Accumulation and Days to Anthesis Relationship in Tobacco Genotypes with an Introgressed QTL Affecting Leaf Number

      Plant breeders and crop managers would benefit from an increased ability to predict the requirements for onset of anthesis in tobacco (Nicotiana tabacum L.). This study was performed to determine the relationship in the field between heat unit (HU) accumulation and the onset of anthesis in tobacco genotypes varying for the zygosity of an introgressed quantitative trait loci (QTL) designated as Many Leaves (Ml) affecting flowering team and leaf number. Three commercially important cultivars or breeding lines (Speight 168, K326, and NCTG-61), their nearly isogenic homozygous (MlMl) and heterozygous (Mlml) counterparts, and three BC6F3 null-segregant (mlml) lines, were evaluated at three locations and over 2 yr. Days to anthesis (DTA) and HU accumulation were determined. (continued)

      Published: August 18, 2016

    • Ahmed Attia and Nithya Rajan
      Within-Season Growth and Spectral Reflectance of Cotton and their Relation to Lint Yield

      Within-season measurements of cotton (Gossypium hirsutum L.) growth and development in response to moisture deficit stress can provide insight into how management practices impact plant health and yield. The objectives were to investigate responses of leaf area index (LAI), normalized difference vegetation index (NDVI), normalized difference water index (NDWI), and crop water stress index (CWSI) and their relation to the lint yield of four cotton cultivars (PHY499, DP1044, PHY375, and FM9170) grown under various irrigation levels for two consecutive growing seasons at Chillicothe, TX. Plants exposed to water stress showed significant LAI, NDVI, and NDWI decrease and CWSI increase compared with well-watered plants. The NDVI reached a plateau value of 0.89 at 82 d after planting (DAP), while NDWI increased steadily to the end of the growing seasons for the high irrigation level. (continued)

      Published: July 14, 2016

    • Jaumer Ricaurte, Jose A. Clavijo Michelangeli, Thomas R. Sinclair, Idupulapati M. Rao and Stephen E. Beebe
      Sowing Density Effect on Common Bean Leaf Area Development

      Sowing density is a major management factor that affects growth and development of grain crops by modifying the canopy light environment and interplant competition for water and nutrients. While the effects of density and plant architecture on static vegetative and reproductive growth traits have been explored previously in common bean (Phaseolus vulgaris L.), there are no reports of intensive measurements of the temporal dynamics on node addition and leaf area development. Such results are reported here from two sites of field experiments where the effects of sowing densities (5, 10, 15, 20, 25, and 35 plants m−2) and genotypes with contrasting plant architectures (two each from growth habits I, II, and III) were assessed. Analysis of the phyllochron (°C node−1) indicated genotype and density effects (but no interaction) on the rate of node addition. (continued)

      Published: June 24, 2016

    • Nicolás Neiff, Samuel Trachsel, Oscar R. Valentinuz, Celsa N. Balbi and Fernando H. Andrade
      High Temperatures around Flowering in Maize: Effects on Photosynthesis and Grain Yield in Three Genotypes

      To aid breeding for heat-tolerant germplasm we analyzed the effects of high temperatures on the CO2 exchange rate (CER), crop growth rate (CGR), kernel number (KN), and grain yield (GY) in a 30-d period bracketing flowering. Field experiments, including three maize (Zea mays L.) hybrids with temperate (Te), tropical (Tr) and temperate × tropical (Tx) adaptation were performed in two experiments (Exp. 1 and 2). Hybrids were subjected to high temperatures induced by shelters during a 15-d period before (H1; preflowering) or after silking (H2; postflowering). (continued)

      Published: June 17, 2016

    • Alessandro Masoni, Silvia Pampana and Iduna Arduini
      Barley Response to Waterlogging Duration at Tillering

      Waterlogging can reduce barley grain yield depending on the sensitivity of the cultivar, the duration, and the stage of development in which waterlogging occurs. This study was conducted to determine whether waterlogging during the tillering stage reduces the grain yield of barley by reducing the spikelet formation and, consequently, the number of kernels per spike, and whether this reduction is related to the length of waterlogging. The impacts of seven waterlogging durations of 4, 8, 12, 16, 20, 40, and 60 d, imposed at 3-leaf and 4-leaf stages were investigated for 2 yr at University of Pisa, Italy, on grain yield, grain yield components, straw, and root dry weight and nitrogen concentration of grain, straw, and roots of two cultivars (‘Amorosa’ and ‘Mattina’) of six-row barley (Hordeum vulgare L.). Cultivar Mattina was tolerant to waterlogging and none of the measured parameters were different from the controls. (continued)

      Published: June 17, 2016


    • Marcelo O. Wallau, Lynn E. Sollenberger, João M.B. Vendramini, Carlos A.M. Gomide, M. Kimberly Mullenix and Kenneth H. Quesenberry
      Performance of Limpograss Breeding Lines under Various Grazing Management Strategies

      Limpograss [Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] is a C4, perennial, stoloniferous grass that is well adapted to poorly drained soils and grows throughout frost-free periods during winter in southern Florida. Its use has increased rapidly in recent decades, but nearly all area in cultivation is planted with one cultivar, ‘Floralta’. A breeding program was initiated to develop improved alternatives to Floralta, resulting in a group of breeding lines requiring evaluation under grazing. (continued)

      Published: August 18, 2016

    • Jessica A. Williamson, Glen E. Aiken, Ernest S. Flynn and Michael Barrett
      Animal and Pasture Responses to Grazing Management of Chemically Suppressed Tall Fescue in Mixed Pastures

      Treatment of toxic endophyte-infected tall fescue [Lolium arundinaceum (Schreb.) Darbysh] with metsulfuran-methyl {Methyl 2-[[[[(4-methoxyl-6-methyl-1,3,5-triazin-2-yl)-amino]carbonyl]amino]sulfonyl] benzoate}, as delivered by Chaparral herbicide (Dow AgroSciences, Indianapolis, IN) can mitigate fescue toxicosis and enhance forage nutritive value by suppressing seedhead emergence. A grazing experiment was conducted with steers (2013) and heifers (2014) to evaluate animal and plant responses to grazing management of mixed cool-season grass pastures treated with Chaparral. Continuous and rotational stocking treatments were assigned to six, 3.0-ha pastures in a randomized complete block design with three replications in 2013 and two replications in 2014. Each pasture had six tester animals, and stocking rates were varied using put-and-take animals. (continued)

      Published: July 28, 2016

    • James P. Muir, Jamie L. Foster and J. Randal Bow
      Establishment-Year Native Perennial Bunchgrass Biomass Yields

      Weak seedling vigor of native North American perennial bunchgrasses may result in poor establishment-season herbage dry matter (DM) yields (HY). Interseeding North American annual legumes as an N source during grassland restoration, pasture establishment, or bioenergy crop seeding might compound this limitation. Our first objective was to evaluate yellow Indiangrass [Sorghastrum nutans (L.) Nash], switchgrass (Panicum virgatum L.), and little bluestem [Schizachyrium scoparium (Michx.) Nash] first-season HY in the southern Great Plains of North America. This took place in north–central Texas on a Windthorst fine sandy loam soil with no irrigation or soil amendments. (continued)

      Published: July 14, 2016

    • Valdson J. Silva, Carlos G. S. Pedreira, Lynn E. Sollenberger, Liliane S. Silva, Junior I. Yasuoka and Ianê C. L. Almeida
      Carbon Assimilation, Herbage Plant-Part Accumulation, and Organic Reserves of Grazed ‘Mulato II’ Brachiariagrass Pastures

      Pasture management, including the control of grazing intensity and fertilization, can trigger plant physiological and morphological responses that affect plant growth and impact stand persistence. The objective of this research was to quantify the effects of three canopy heights (10, 25, and 40 cm), maintained by mimicking continuous stocking, and two N rates (50 and 250 kg ha−1 yr−1) on canopy carbon exchange rate (CER), plant-part accumulation, and organic reserves of ‘Mulato II’ brachiariagrass hybrid (Brachiaria brizantha × B. decumbens × B. ruziziensis), also known as Convert HD 364 (Dow AgroSciences, São Paulo, Brazil) during two summer rainy seasons in Piracicaba, Brazil. (continued)

      Published: July 14, 2016

    • Jacob M. Jungers, Mary Brakke, Aaron Rendahl and Craig C. Sheaffer
      Identifying Base Temperature for Alfalfa Germination: Implications for Frost Seeding

      Frost seeding alfalfa (Medicago sativa L.) can be convenient and economical for establishing or renovating forage stands; however, premature seedling emergence triggered by unusually warm temperatures followed by fatally cold temperatures can lead to seedling mortality and stand failure. Delaying germination could improve establishment success in frost-seeded stands. Our objective was to measure the effect of temperature and water potential (Ψ) on germination across a range of alfalfa varieties. Germination rate (1 divided by days to 50% germination) was estimated for 11 varieties at nine constant temperatures (−1.1 to 10°C) and three Ψ (0, −0.2, and −0.6 MPa). (continued)

      Published: June 24, 2016

    • José C.B. Dubeux, Nicolas DiLorenzo, Ann Blount, Cheryl Mackowiak, Erick R.S. Santos, Hiran M.S. Silva, Martin Ruiz-Moreno and Tessa Schulmeister
      Animal Performance and Pasture Characteristics on Cool-Season Annual Grass Mixtures in North Florida

      Cool-season forage mixtures are an option for extending the length of the grazing season. Small grains have a different growth distribution than annual ryegrass and may increase livestock gain per area. This 2-yr grazing study tested three small grain–annual ryegrass mixtures: (i) cereal rye (Secale cereale L. ‘FL401’)–annual ryegrass (Lolium multiflorum Lam. (continued)

      Published: June 24, 2016


    • E.A. Lee, W. Deen, M.E. Hooyer, A. Chambers, G. Parkin, R. Gordon and A.K. Singh
      Involvement of Year-to-Year Variation in Thermal Time, Solar Radiation and Soil Available Moisture in Genotype-by-Environment Effects in Maize

      Year-to-year variability in temperature, precipitation, and solar radiation is increasing due to global climate change. This enhanced variation will likely lead to more frequent and larger genotype-by-environment interaction (G × E) effects impacting genetic gains from selection. In this study G × E effects are examined in the absence of genetic variation for thermal time requirements (i.e., phenology), with an understanding of which physiological mechanisms are responsible for genotypic differences in grain yield, using a series of developmental windows, and in the context of fully characterized environments. Using a set of hybrid RILs of the classic Iodent × Stiff Stalk heterotic pattern, we demonstrate that the hybrid RILs are phenologically uniform and that grain yield differences are due primarily to genetic variation in dry matter accumulation during the grain filling period. (continued)

      Published: February 12, 2016


    • A. Meier and D.A. Halterman
      Structural Variation within the Potato Ve Gene Locus and Correlation with Molecular Marker Analysis

      Plant breeders rely on molecular markers to guide the selection of traits that are difficult to phenotype or that show wide variation in field trials as they seek to uncover the intricate relationship between an organism’s genotype and resulting phenotype. Specificity of molecular markers in wild potato (Solanum spp.) and other less-adapted germplasm is complicated by the existence of homologous gene clusters. This study examines the consistency and effectiveness of two previously published cleaved amplified polymorphic sequence (CAPS) markers that have been shown to predict Verticillium wilt (VW) resistance. The genome of resistant diploid potato clone C287 was resequenced, and examination of the Ve locus indicated only two homologous regions when compared with the three found in the reference potato genome DM1-3. (continued)

      Published: August 18, 2016

    • Xiangyan Zhou, Ning Zhang, Jiangwei Yang and Huaijun Si
      Functional Analysis of Potato CPD Gene: A Rate-Limiting Enzyme in Brassinosteroid Biosynthesis under Polyethylene Glycol-Induced Osmotic Stress

      The constitutive photomorphogenesis and dwarf (CPD) gene was initially isolated from an Arabidopsis thaliana (L.) Heynh. cpd mutant and encodes C-3 oxidase as a key rate-limiting enzyme in the brassinosteroids (BRs) biosynthesis pathway. For a better understanding of the molecular mechanism of CPD gene overexpression in potato (Solanum tuberosum L.) and CPD-overexpressing potato plant tolerance to polyethylene glycol (PEG)-induced osmotic stress, CPD gene was cloned by reverse transcription–polymerase chain reaction (RT-PCR) from potato. The coding region was 1473 bp and encoded a deduced protein of 490 amino acids. (continued)

      Published: June 24, 2016


    • Apostolos Kalivas, Ioannis Ganopoulos, Irene Bosmali, Eleni Tsaliki, Maslin Osathanunkul, Aliki Xanthopoulou, Theodoros Moysiadis, Evangelia Avramidou, Ioannis Grigoriadis, Antonios Zambounis, Athanasios Tsaftaris, Irini Nianiou-Obeidat and Panagiotis Madesis
      Genetic Diversity and Structure of Tobacco in Greece on the Basis of Morphological and Microsatellite Markers

      Oriental tobacco varieties have greater aroma value, and consumer demand for these varieties is now greater than ever. Yet our knowledge of morphological and genetic diversity within diverse gene pools of cultivated oriental tobacco (Nicotiana tabacum L.) varieties is limited. Phenotypic and genetic analysis of these genotypes is important for the improvement of tobacco varieties. Information on morphology and genetics could help toward future germplasm maintenance and selection of suitable materials for breeding elite varieties. (continued)

      Published: June 29, 2016

    • Amol Nankar, Lois Grant, Paul Scott and Richard C. Pratt
      Agronomic and Kernel Compositional Traits of Blue Maize Landraces from the Southwestern United States

      Diverse landraces of maize have been cultivated for centuries in the southwestern United States and northern Mexico primarily for human food consumption. A striking feature of these landraces is the wide array of kernel colors displayed. Traditional cultivation is declining, but blue maize has received increasing commercial interest due to rising consumer demand for unique food products with health benefits and special culinary uses. We evaluated grain yield, agronomic and morphological traits, and analyzed the kernel biochemical composition of five blue and one purple landraces representative of diversity in the Southwest. (continued)

      Published: June 24, 2016


    • Sarah M. Grogan, Josh Anderson, P. Stephen Baenziger, Katherine Frels, Mary J. Guttieri, Scott D. Haley, Ki-Seung Kim, Shuyu Liu, Gregory S. McMaster, Mark Newell, P. V. Vara Prasad, Scott D. Reid, Kyle J. Shroyer, Guorong Zhang, Eduard Akhunov and Patrick F. Byrne
      Phenotypic Plasticity of Winter Wheat Heading Date and Grain Yield across the US Great Plains

      Phenotypic plasticity describes the range of phenotypes produced by a single genotype in different environments. We quantified the extent of phenotypic plasticity (evaluated as responsiveness to varying environmental conditions) of thermal time to heading and grain yield in 299 hard winter wheat (Triticum aestivum L.) genotypes from the US Great Plains. The genotypes, which included advanced breeding lines and recent and historic cultivars, were evaluated in 11 environments in 2011–2012 and 2012–2013. The average number of days from 1 January to heading across environments ranged from 109 to 150, and the cumulative growing degree days (GDD) from 1 January to heading ranged from 730 to 1112 GDD. (continued)

      Published: May 27, 2016

    • Ben J. Hayes, Hans D. Daetwyler and Mike E. Goddard
      Models for Genome × Environment Interaction: Examples in Livestock

      In livestock, genotype × environment interaction (G × E) has been widely investigated, with genotype defined at the level of subspecies, breeds, individual animals within a breed (for example performance of offspring of elite sires across environments), and genotypes at single-nucleotide polymorphisms (SNPs). Environments can be described by category (e.g., tropical vs. temperate, high vs. low farm input levels, countries) and by continuous variables such as temperature. (continued)

      Published: May 6, 2016

    • K. Kleinknecht, J. Möhring, F. Laidig, U. Meyer and H.P. Piepho
      A Simulation-Based Approach for Evaluating the Efficiency of Multienvironment Trial Designs

      Plant breeding and official variety testing involve the challenge to design multienvironmental trials in several years and locations. Several variables influence the performance and, therefore, the possible selection gain of such trials. We provide a simulation-based approach using SAS to vary these variables and to allow a comparison of different scenarios for the design of series of trials regarding selection gain. Our approach builds on the FORTRAN software tool SELSYS. (continued)

      Published: March 11, 2016

    • Mark Cooper, Frank Technow, Carlos Messina, Carla Gho and L. Radu Totir
      Use of Crop Growth Models with Whole-Genome Prediction: Application to a Maize Multienvironment Trial

      High throughput genotyping, phenotyping, and envirotyping applied within plant breeding multienvironment trials (METs) provide the data foundations for selection and tackling genotype × environment interactions (GEIs) through whole-genome prediction (WGP). Crop growth models (CGM) can be used to enable predictions for yield and other traits for different genotypes and environments within a MET if genetic variation for the influential traits and their responses to environmental variation can be incorporated into the CGM framework. Furthermore, such CGMs can be integrated with WGP to enable whole-genome prediction with crop growth models (CGM-WGP) through use of computational methods such as approximate Bayesian computation. We previously used simulated data sets to demonstrate proof of concept for application of the CGM-WGP methodology to plant breeding METs. (continued)

      Published: February 12, 2016

    • Marcos Malosetti, Daniela Bustos-Korts, Martin P. Boer and Fred A. van Eeuwijk
      Predicting Responses in Multiple Environments: Issues in Relation to Genotype × Environment Interactions

      Prediction of the phenotypes for a set of genotypes across multiple environments is a fundamental task in any plant breeding program. Genomic prediction (GP) can assist selection decisions by combining incomplete phenotypic information over multiple environments (MEs) with dense sets of markers. We compared a range of ME-GP models differing in the way environment-specific genetic effects were modeled. Information among environments was shared either implicitly via the response variable, or by the introduction of explicit environmental covariables. (continued)

      Published: February 5, 2016

    • Bettina Lado, Pablo González Barrios, Martín Quincke, Paula Silva and Lucía Gutiérrez
      Modeling Genotype × Environment Interaction for Genomic Selection with Unbalanced Data from a Wheat Breeding Program

      Genomic selection (GS) has successfully been used in plant breeding to improve selection efficiency and reduce breeding time and cost. However, there is not a clear strategy on how to incorporate genotype × environment interaction (GEI) to GS models. Increased prediction accuracy could be achieved using mixed models to exploit GEI by borrowing information from other environments. The objective of this work was to compare strategies to exploit GEI in GS using mixed models. (continued)

      Published: January 29, 2016

    • Jakub Paderewski, Hugh G. Gauch, Wieslaw Mądry and Edward Gacek
      AMMI Analysis of Four-Way Genotype × Location × Management × Year Data from a Wheat Trial in Poland

      Grain yield data of winter wheat (Triticum aestivum L.) trials in Poland had a four-way factorial design of 24 genotypes by 20 locations by two managements by 3 yr. The experimental design had genotype–management strip plots with two replications for genotypes, with somewhat more genotypes than the 24 having no missing data. The research objectives were to extend additive main effects and multiplicative interactions (AMMI) analysis from two-way to higher-way datasets to reduce spurious complexity originating from noise, delineate wheat mega-environments in Poland, and make genotype recommendations within each mega-environment. Statistical analysis began with adjusting the yield estimates using the strip-plot experimental design and then combining the results in a genotype × location × management × year (GLMY) table. (continued)

      Published: September 25, 2015

    • Weikai Yan
      Analysis and Handling of G × E in a Practical Breeding Program

      Genotype by environment interaction (GE) is a reality in plant breeding and crop production, and has to be dealt with. There are but two viable options to deal with GE: to utilize it or to avoid it, depending on whether it is repeatable. Repeatable GE can be selected for (utilized) whereas unrepeatable GE has to be selected against (avoided). To utilize GE involves identifying repeatable GE, dividing the target region into subregions or megaenvironments (ME) based on the repeatable GE pattern, and selecting within ME. (continued)

      Published: December 3, 2015

    • José Crossa, Gustavo de los Campos, Marco Maccaferri, Roberto Tuberosa, J. Burgueño and Paulino Pérez-Rodríguez
      Extending the Marker × Environment Interaction Model for Genomic-Enabled Prediction and Genome-Wide Association Analysis in Durum Wheat

      The marker × environment interaction (M×E) genomic model can be used to generate predictions for untested individuals and identify genomic regions in which effects are stable across environments and others that show environmental specificity. The objectives of this study were (i) to extend the M×E model using priors that produce shrinkage and variable selection such as Bayesian ridge regression (BRR) and BayesB (BB), respectively, and (ii) to evaluate the genomic prediction accuracy of M×E, single-environment, and across-environment models using a multiparental durum wheat (Triticum turgidum L. spp. duram) population characterized for grain yield (GY), grain volume weight (GVW), 1000-kernel weight (GWT), and heading date (HD) in four environments. (continued)

      Published: December 3, 2015


    • John C. Inguagiato and Karl Guillard
      Foliar N Concentration and Reflectance Meters to Guide N Fertilization for Anthracnose Management of Annual Bluegrass Putting Green Turf

      Site-specific management using objective assays to determine N requirement based on canopy reflectance could improve current recommendations for cultural control of anthracnose (Colletotrichum cereale Manns sensu lato Crouch, Clarke, and Hillman). The objectives of this study were to determine the relationships among foliar sap nitrate–nitrogen (NO3–N) concentrations, canopy reflectance indices (normalized difference vegetation index [NDVI] and chlorophyll index [CI]), foliar total N concentrations, and N rate on anthracnose severity in annual bluegrass (ABG), Poa annua L. f. reptans (Hausskn) T. (continued)

      Published: August 12, 2016

    • B.P. Hodges, C.M. Baldwin, B. Stewart, M. Tomaso-Peterson, J.D. McCurdy, E.K. Blythe and H.W. Philley
      Quantifying a Daily Light Integral for Establishment of Warm-Season Cultivars on Putting Greens

      A major constraint for successful ultradwarf bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy] putting green establishment is a reduced-light environment (RLE) because of the overall poor shade tolerance of bermudagrass. Currently, no research studies have determined the light requirement for warm-season putting green cultivar establishment. (continued)

      Published: June 17, 2016

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