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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 crop science research. Articles are compiled into bimonthly issues at dl.sciencesocieties.org/publications/cs, which includes the complete archive. Citation | Articles posted here are considered published and may be cited by the doi.

Example: 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.

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Current issue: Crop Sci. 55(4)


    • Alyssa W. Beavers, A. Susana Goggi, Manju B. Reddy, Adrienne Moran Lauter and M. Paul Scott
      Recurrent Selection to Alter Grain Phytic Acid Concentration and Iron Bioavailability

      Iron is an important micronutrient and Fe deficiency is a global health concern. Phytic acid inhibits Fe absorption and cannot be digested by monogastric livestock or humans. High phytate concentration in staple crops may be one of the contributing factors for the high incidence of anemia in developing countries because of its inhibiting effect on Fe absorption. In seeds, it serves as the main storage compound for P. (continued)

      Published: July 2, 2015

    • Mary J. Guttieri, P. Stephen Baenziger, Katherine Frels, Brett Carver, Brian Arnall, Shichen Wang, Eduard Akhunov and Brian M. Waters
      Prospects for Selecting Wheat with Increased Zinc and Decreased Cadmium Concentration in Grain

      Wheat (Triticum aestivum L.) is a primary staple cereal and significant source of mineral nutrients in human diets. Therefore, increasing concentration of the essential mineral, Zn, and decreasing concentration of the toxic mineral, Cd, could significantly improve human health. Because plant mechanisms for uptake and translocation of Cd and Zn are related, we assessed both Cd and Zn concentration to evaluate their independence in hard winter wheat germplasm. Grain Cd concentrations of some genotypes grown in Nebraska trials were above the Codex guidance level (0.2 mg kg–1), and highly repeatable differences in grain Cd were found between pairs of low and moderate-Cd commercial cultivars. (continued)

      Published: June 12, 2015

    • Brian K. Pfeiffer and William L. Rooney
      Sunlight Induces Black Color and Increases Flavonoid Levels in the Grain of Sorghum Line Tx3362

      The grain sorghum [Sorghum bicolor (L.) Moench.] line ‘Tx3362’ has a uniformly black pericarp color when produced under summer production conditions and it also contains high levels of 3-deoxyanthocyanidins (3-DOAs) in the bran layers of the grain. Consequently, Tx3362 has high levels of antioxidant activity and is a source of natural pigmentation that can be used as natural food coloring. However, prior research indicates that the black color is not fully penetrant in all environments. Specifically, black sorghum panicles shaded from sunlight between flowering and physiological maturity are dark red in color. (continued)

      Published: June 12, 2015

    • M.J. Morrison, E.R. Cober, J.A. Frégeau-Reid and P. Seguin
      Changes in Lutein and Tocopherol Concentrations in Soybean Cultivars Released Across Seven Decades in the Short-Season Region

      Lutein and α-tocopherol (α-toc) are antioxidant compounds beneficial for human health. Soybean [Glycine max (L). Merr.] contains relatively high concentrations of these compounds, and increasing them through plant breeding may be beneficial to human nutrition as well as provide a marketable seed trait in food-type soybean. Our objective was to determine if there have been changes in lutein and tocopherol concentrations in short-season soybean cultivars. (continued)

      Published: February 3, 2015


    • Lisa-Marie Krchov and Rex Bernardo
      Relative Efficiency of Genomewide Selection for Testcross Performance of Doubled Haploid Lines in a Maize Breeding Program

      In a simple scheme for genomewide selection in maize (Zea mays L.), a subset of n out of N doubled haploid (DH) lines from a biparental cross are genotyped and phenotyped in testcross combination. The n lines are then used as a training population to predict the performance of the remaining Nn lines. Our objectives were to (i) determine whether or not this scheme for genomewide selection is more efficient than phenotypic selection under a fixed budget and (ii) give recommendations for implementing this genomewide selection scheme during maize line development. From empirical data across multiple populations, testers, years, and locations, we assessed the observed and expected gains from phenotypic selection and genomewide selection under different budget scenarios. (continued)

      Published: July 29, 2015

    • Patricia Mabel Aguilera, Florencia Galdeano, Camilo Luis Quarin, Juan Pablo Amelio Ortiz and Francisco Espinoza
      Inheritance of Aposporous Apomixis in Inter-specific Hybrids Derived from Sexual Paspalum plicatulum and Apomictic Paspalum guenoarum

      Apomictic Paspalum plicatulum Michx. and P. guenoarum Arechav. are promising candidates for forage grass development in tropical regions. (continued)

      Published: July 17, 2015

    • Christopher M. Kaiser, Lindsay V. Clark, John A. Juvik, Thomas B. Voigt and Erik J. Sacks
      Characterizing a Miscanthus Germplasm Collection for Yield, Yield Components, and Genotype × Environment Interactions

      Miscanthus is among the best biomass crops for temperate environments but current production is almost entirely associated with a single sterile clone of Miscanthus × giganteus J.M.Greef , Deuter ex Hodk., Renvoize. To create additional and improved cultivars, characterization of available germplasm is needed for biomass traits and genotype × environment (G × E) interactions. Additionally, there has been little guidance on how to best allocate experimental units in Miscanthus breeding trials. The purpose of this study was to quantify genetic diversity for biomass yield in a Miscanthus germplasm collection of 98 accessions that represent publicly available materials in North America, determine the predictive value of three putative yield component traits for estimating yield, and quantify the relative importance of G × E and error variances for estimating genotypic values. (continued)

      Published: July 17, 2015

    • Michael D. Casler, Jerome H. Cherney, E. Charles Brummer and Bruce S. Dien
      Designing Selection Criteria for Use of Reed Canarygrass as a Bioenergy Feedstock

      Reed canarygrass (Phalaris arundinacea L.) is a perennial C3 grass with a circumglobal distribution in the Northern Hemisphere and adaptation to a wide range of environmental conditions. This species is currently under development as a bioenergy feedstock in North America and Europe. Thus, the objectives of this study were to (i) quantify genetic variation for biomass quality traits of reed canarygrass cultivars and accessions, (ii) determine the relationships for biomass yield with reed canarygrass quality traits, and (iii) identify favorable and attainable breeding objectives for biomass yield and quality traits of reed canarygrass. Eighty cultivars or accessions were grown at five field locations and evaluated for 26 biomass quality traits in 2006 through 2008. (continued)

      Published: July 17, 2015

    • M. F. Paget, L. A. Apiolaza, J. A. D. Anderson, R. A. Genet and P. A. Alspach
      Appraisal of Test Location and Variety Performance for the Selection of Tuber Yield in a Potato Breeding Program

      Differences in trait responses of genotypes across environments, or genotype × environment interactions (G × E), hinder the progress of genetic improvement. Characterization of these effects helps to determine breeding strategies and improve resource allocation in a cultivar development program. This study used historical multienvironment trial (MET) data (34 trials in five locations) for the analysis of marketable yield of advanced selections in a New Zealand potato (Solanum tuberosum L.) breeding program. A factor analytic (FA) model was used for the analysis of these MET data. (continued)

      Published: July 17, 2015

    • Xuehui Li, Baldomero Alarcón-Zúñiga, Junmei Kang, M. Hammad Nadeem Tahir, Qingzhen Jiang, Yanling Wei, Rafael Reyno, Joseph G. Robins and E. Charles Brummer
      Mapping Fall Dormancy and Winter Injury in Tetraploid Alfalfa

      Alfalfa (Medicago sativa L.) is a widely planted perennial forage crop. Fall dormancy is generally negatively correlated with winter injury in alfalfa. To understand the genetic basis of the two traits, we identified quantitative trait loci (QTL) controlling autumn growth and winter injury using a tetraploid alfalfa F1 population. In total, 601 marker alleles were scored from 78 restriction fragment length polymorphism (RFLP), 123 simple-sequence repeat (SSR), and 48 single nucleotide polymorphism (SNP) markers. (continued)

      Published: July 17, 2015

    • Desmi Chandrasena, Yang Wang, Carmille Bales, Jiazheng Yuan, Cuihua Gu and Dechun Wang
      Pyramiding rag 3, rag 1b, rag 4, and rag 1c Aphid-Resistant Genes in Soybean Germplasm

      The soybean aphid, Aphis glycines, poses a significant threat to soybean [Glycine max (L.) Merr.]. Use of resistant cultivars is one of the most effective control tactics. Pyramiding multiple resistance genes has great potential to provide durable resistance to soybean aphids. The objectives of this study were to evaluate soybean aphid damage on soybean lines containing individual or a combination of rag3, rag4, rag1b, and rag1c aphid-resistant genes, and to identify the genetic interactions of these loci in the greenhouse and field conditions. (continued)

      Published: July 17, 2015

    • Ian M. Ray, Yuanhong Han, Lei E, Chris D. Meenach, Nicholas Santantonio, Mary K. Sledge, Christopher A. Pierce, Tracy M. Sterling, Rossio K. Kersey, Hem Singh Bhandari and Maria J. Monteros
      Identification of Quantitative Trait Loci for Alfalfa Forage Biomass Productivity during Drought Stress

      Large portions of the world’s arable acreage experience water stress on a regular basis. Improving crop productivity in such drought-prone environments is a critical breeding objective. The goal of this study was to detect quantitative trait loci (QTL) associated with alfalfa (Medicago sativa L.) forage productivity during drought stress. Two first-generation backcross (BC1) mapping populations (n = 253) derived from a cross between M. (continued)

      Published: July 17, 2015

    • Esteban F. Rios, Kevin E. Kenworthy and Patricio R. Munoz
      Association of Phenotypic Traits with Ploidy and Genome Size in Annual Ryegrass

      Annual ryegrass (Lolium multiflorum Lamarck) is planted annually on more than 1 million ha of pastures in the southeastern United States. The exact ploidy level and genome size of the annual ryegrass germplasm collection (USDA–ARS, Germplasm Resources Information Network, GRIN) are unknown and the future use of this germplasm relies on their determination. The study was conducted to (i) estimate the ploidy level and determine the DNA content of 139 accessions from the GRIN collection, 15 experimental lines, and 13 commercial cultivars through flow cytometry; and (ii) identify morphological and agronomic characteristics that could be used to differentiate diploid from tetraploid annual ryegrass. A total of 140 diploid and 27 tetraploid lines were successfully identified through flow cytometry. (continued)

      Published: July 17, 2015

    • Mohsen Mohammadi, Tyler Tiede and Kevin P. Smith
      PopVar: A Genome-Wide Procedure for Predicting Genetic Variance and Correlated Response in Biparental Breeding Populations

      Predicting genetic variances of biparental populations has been a long-standing goal for plant breeders. The ability to discriminate among crosses with similarly predicted high means but different levels of genetic variance (VG) should improve the effectiveness of breeding. We developed a procedure that uses established progeny simulation and genomic prediction strategies to predict the population mean (μ) and VG, the mean of the desired 10% of the progeny (superior progeny mean [μsp]), and correlated responses of multiple traits for biparental populations. The proposed procedure, PopVar, is herein demonstrated using a training population (TP) composed of 383 breeding lines that have been genotyped and phenotyped for yield and deoxynivalenol (DON). (continued)

      Published: June 26, 2015

    • John M. Hickey, Gregor Gorjanc, Rajeev K. Varshney and Carl Nettelblad
      Imputation of Single Nucleotide Polymorphism Genotypes in Biparental, Backcross, and Topcross Populations with a Hidden Markov Model

      Genomic selection offers great potential to increase the rate of genetic improvement in plant breeding programs. The ability to accurately impute missing genotypes for a large number of individuals, screened with low marker density, at low cost is crucial for achieving this. In this research an existing general algorithm for tracing allele inheritance in known pedigrees was modified to enable genotype imputation in specific crosses (biparental, backcross, and topcross) that are common in plant breeding. The extension was tested with a series of representative simulated examples of these crosses. (continued)

      Published: June 26, 2015

    • B.C. Bowman, J. Chen, J. Zhang, J. Wheeler, Y. Wang, W. Zhao, S. Nayak, N. Heslot, H. Bockelman and J.M. Bonman
      Evaluating Grain Yield in Spring Wheat with Canopy Spectral Reflectance

      Worldwide, improving grain yield is the most important target for wheat (Triticum aestivum L.) breeders. Fast, cost-effective, and nondestructive phenotyping methods for important traits are needed to increase the efficiency of cultivar development. The present study tested canopy spectral reflectance (CSR) as a potential high-throughput method for assessing wheat grain yield in a diverse set of 540 spring-habit accessions from the USDA–ARS National Small Grains Collection. Plots were grown under irrigated (IR) and terminal drought (DR) treatments over two growing seasons, and CSR was measured at several growth stages in each year. (continued)

      Published: June 26, 2015

    • Rafael Reyno, Daniel Real and E. Charles Brummer
      Comparison of Two Selection Methods for Tolerance to Acidic, Aluminum-rich Soil in Alfalfa

      In acid soils (pHwater <5), Al becomes toxic, affecting alfalfa (Medicago sativa L.) root growth and development. In the southeastern United States, Al toxicity and its associated deficiencies are the most significant factors limiting alfalfa production. This study aimed to compare genetic gain for acid or Al tolerance as assessed by seedling biomass production in acidic soil under greenhouse conditions using phenotypic recurrent selection with gridding (PRSG) and among and within family selection (AWFS) in ‘Bulldog 805’ and PRSG in the germplasm ‘Cultivated Alfalfa at the Diploid Level’ (CADL) for two cycles. Selection was based on aerial biomass production or visual score 60 d after germination in Al-rich acidic (unlimed, UL) soil and limed soil. (continued)

      Published: June 26, 2015

    • Lorenna L. Sousa, Aline O. Gonçalves, Maria C. Gonçalves-Vidigal, Giselly F. Lacanallo, Andrea C. Fernandez, Halima Awale and James D. Kelly
      Genetic Characterization and Mapping of Anthracnose Resistance of Common Bean Landrace Cultivar Corinthiano

      The objectives of this study were to characterize the genetic resistance in the Andean common bean (Phaseolus vulgaris L.) cultivar Corinthiano to races 8, 65, 89, and 2047 of Colletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara through inheritance and allelism tests and to map the source of resistance. Corinthiano was crossed with cultivars Michelite, Michigan Dark Red Kidney (MDRK), Cornell 49-242, Mexico 222, PI 207262, TO, TU, AB 136, G 2333, Jalo Listras Pretas (JLP), Jalo Vermelho (JV), BAT 93, Ouro Negro, AND 277, Pitanga, SEL 1308, H1 line, and Crioulo 159 to generate F2 populations. Inheritance tests conducted in F2 population and F2:3 families from the cross Corinthiano (resistant [R]) × Cornell 49-242 (susceptible [S]) inoculated with race 2047 showed segregation that fit ratios of 3R:1S and 1RR:2Rr:1rr, respectively, indicating the action of a dominant resistance gene in Corinthiano. (continued)

      Published: June 26, 2015

    • Marilyn L. Warburton, Juliet D. Tang, Gary L. Windham, Leigh K. Hawkins, Seth C. Murray, Wenwei Xu, Debbie Boykin, Andy Perkins and W. Paul Williams
      Genome-Wide Association Mapping of Aspergillus flavus and Aflatoxin Accumulation Resistance in Maize

      Contamination of maize (Zea mays L.) with aflatoxin, produced by the fungus Aspergillus flavus Link, has severe health and economic consequences. Efforts to reduce aflatoxin accumulation in maize have focused on identifying and selecting germplasm with natural host resistance factors, and several maize lines with significantly reduced aflatoxin accumulation have been identified. Past linkage mapping studies have identified quantitative trait loci (QTL) that consistently reduce aflatoxin levels in maize. In addition, an association mapping panel of 300 maize inbred lines was previously created specifically for the dissection of aflatoxin accumulation resistance. (continued)

      Published: June 26, 2015

    • Sidi Boubacar Ould Estaghvirou, Joseph O. Ogutu and Hans-Peter Piepho
      How Genetic Variance and Number of Genotypes and Markers Influence Estimates of Genomic Prediction Accuracy in Plant Breeding

      Genomic prediction is revolutionizing plant and animal breeding, but its accuracy is affected by multiple factors. Here, we simulate 24 scenarios, each with 1000 datasets, to evaluate how varying the genetic variance (small, large), number of genotypes (180, 360, 540, and 698), and markers (2912, 5823, and 11,646) affects the relative performance of seven competing methods for accuracy estimation in genomic prediction in plant breeding programs. Each method was used to estimate predictive accuracy. The estimates were then compared between methods and, for each method, with the simulated true accuracy for each scenario as the gold standard. (continued)

      Published: June 26, 2015

    • A. C. Varella, D. K. Weaver, J. D. Sherman, N. K. Blake, H. Y. Heo, J. R. Kalous, S. Chao, M. L. Hofland, J. M. Martin, K. D. Kephart and L. E. Talbert
      Association Analysis of Stem Solidness and Wheat Stem Sawfly Resistance in a Panel of North American Spring Wheat Germplasm

      The expanding geographical range of wheat stem sawfly (WSS) damage, coupled with the limited number of effective control measures, calls for a need to better characterize and explore the genetic variability for resistance in wheat (Triticum aestivum L.) germplasm from North America. An association-mapping analysis for stem solidness and wheat stem sawfly resistance was conducted using a set of 244 elite spring wheat lines from 10 North American breeding programs. Three previously identified quantitative trait loci (QTL) for resistance were confirmed, including QTL for stem solidness, heading date, and stem cutting. Three new QTL on chromosomes 2A, 3A, and 5B were identified to be associated with larval mortality and a QTL associated with early stem solidness was identified on chromosome 5D. (continued)

      Published: June 26, 2015

    • Valerio Hoyos-Villegas, Wezi Mkwaila, Perry B. Cregan and James D. Kelly
      Quantitative Trait Loci Analysis of White Mold Avoidance in Pinto Bean

      White mold is a major disease of common bean (Phaseolus vulgaris L.) grown in temperate production areas. The objective of this study was to use single nucleotide polymorphism (SNP) markers from the BARCBean6K_3 BeadChip to identify quantitative trait loci (QTL) associated with traits related to white mold resistance in common bean. A recombinant inbred line (RIL) population from a cross of disease-tolerant pinto line AN-37 and disease-susceptible line P02630 was evaluated in Michigan for 4 yr under white mold pressure. Traits evaluated included disease incidence, the numbers of days to flower and to maturity, canopy height, lodging, seed yield, and 100-seed weight. (continued)

      Published: June 26, 2015

    • Jennifer J. Trapp, Carlos A. Urrea, Perry B. Cregan and Phillip N. Miklas
      Quantitative Trait Loci for Yield under Multiple Stress and Drought Conditions in a Dry Bean Population

      Terminal and intermittent drought limits dry bean (Phaseolus vulgaris L.) production worldwide. Tolerance to drought exists but is difficult to breed for because of inconsistent expression across environments. Our objective was to identify quantitative trait loci (QTL) conditioning yield in a recombinant inbred line (RIL) population with consistent expression across multiple drought-stress environments. We tested 140 RILs from ‘Buster’ pinto (susceptible)/‘Roza’ pink (tolerant) for yield under multiple stresses (intermittent drought, compaction, and low fertility) across 3 yr and terminal drought across four location-years. (continued)

      Published: June 12, 2015

    • Naoya Yamaguchi, Fumio Taguchi-Shiobara, Takashi Sayama, Tomoaki Miyoshi, Michio Kawasaki, Masao Ishimoto and Mineo Senda
      Quantitative Trait Loci Associated with Tolerance to Seed Cracking under Chilling Temperatures in Soybean

      In Hokkaido, northern Japan, soybean [Glycine max (L.) Merr.] crops are damaged by cold weather. Chilling temperatures result in the appearance of cracked seeds (CSs) in soybean crops, especially those grown in eastern and northern Hokkaido. The seed coats of CSs are severely split on the dorsal side, and the cotyledons are exposed and frequently separated. The occurrence of CSs causes unstable production because these seeds have no commodity value. (continued)

      Published: July 2, 2015

    • Tingting Wu, Shi Sun, Caijie Wang, Wencheng Lu, Bincheng Sun, Xiqing Song, Xiaozeng Han, Tai Guo, Weiqun Man, Yanxi Cheng, Jianguang Niu, Lianshun Fu, Wenwen Song, Bingjun Jiang, Wensheng Hou, Cunxiang Wu and Tianfu Han
      Characterizing Changes from a Century of Genetic Improvement of Soybean Cultivars in Northeast China

      The first soybean [Glycine max (L.) Merr.] breeding program in China was established in the northeast in 1913. A trend analysis of widely grown cultivars across Chinese soybean breeding history may provide a better perspective on the genetic progress in soybean. The objective of the current study was to assess the genetic change of 15 phenological, yield, and agronomic traits on widely grown cultivars in northeast China. Sixty-four soybean cultivars representing a span of 84 yr (1923–2007) of release were included. (continued)

      Published: July 2, 2015

    • Sayareh Irani, Mohammad Mahdi Majidi, Aghafakhr Mirlohi, Mostafa Karami and Mahnaz Zargar
      Response to Drought Stress in Sainfoin: Within and Among Ecotype Variation

      Ecotypes of sainfoin (Onobrychis viciifolia Scop.) have not been extensively studied, and knowledge about their variation is generally limited. In the present study, 100 sainfoin genotypes from 10 ecotypes were clonally propagated and evaluated under water-stressed and nonstressed conditions for 2 yr. Among- and within-ecotype variation plus heritability of agronomic, morphological, and physiological traits were estimated and the associations of traits were determined. For most of the measured traits among- and within-ecotype effects were significant. (continued)

      Published: July 2, 2015

    • Shannon R. M. Pinson, Yueguang Wang and Rodante E. Tabien
      Mapping and Validation of Quantitative Trait Loci Associated with Tiller Production in Rice

      An increase in early tiller production is desired in rice (Oryza sativa L.) to increase yield potential and enhance ability to shade and suppress weeds. Unfortunately, tiller production and survival are sensitive to many environmental cues, making tillering pattern a difficult trait to reliably evaluate in field plots. The present objective was to use pot-grown plants where seeding depth and the environment could be controlled to identify quantitative trait loci (QTLs) associated with rate of seedling development (seedling leaf number, SLN) and tiller production (tiller number, TN) as well as the node from which the first tiller originated (N1T). The QTLs were identified in two related mapping populations, the first being a set of 280 ‘Lemont’ × ‘TeQing’ recombinant inbred lines (RILs) observed over four trials, in which nine QTLs associated with TN, three for SLN, and two for N1T were detected. (continued)

      Published: June 12, 2015

    • S. M. Laurie, M. Booyse, M. T. Labuschagne and M. M. Greyling
      Multienvironment Performance of New Orange-Fleshed Sweetpotato Cultivars in South Africa

      Vitamin A deficiency is a serious health problem in South Africa, as in several parts of the world. One strategy to combat micronutrient deficiency is through biofortification, particularly through orange-fleshed sweetpotato [Ipomoea batatas (L.) Lam]. Previously, a shortage existed in South Africa of orange-fleshed genotypes with a combination of high dry mass, good yield, and good taste. Local cream-fleshed parents and orange-fleshed US introductions were used in the local polycross program. (continued)

      Published: June 12, 2015

    • Suchismita Mondal, Ravi P. Singh, Julio Huerta-Espino, Zakaria Kehel and Enrique Autrique
      Characterization of Heat- and Drought-Stress Tolerance in High-Yielding Spring Wheat

      Unpredictable temperature and rainfall patterns have increased global concerns about sustaining current levels of wheat (Triticum aestivum L.) production. Although many international breeding programs are focused on developing high-temperature and drought-stress tolerant wheat varieties, changing weather patterns has increased the need to develop widely adaptable wheat varieties. Research was conducted to identify the potential resilience of spring wheat lines to heat and drought stresses and to define phenotypic and physiological traits that are associated with stress adaptation. A trial consisting of 28 newly developed spring wheat lines and two checks was tested under optimal, heat-, and drought-stress conditions for 2 yr in Ciudad Obregon, Mexico. (continued)

      Published: June 12, 2015

    • Nino Brown, C. Wayne Smith, Steve Hague, Dick Auld, Eric Hequet, Kolbyn Joy and Don Jones
      Within-Boll Yield Characteristics and Their Correlation with Fiber Quality Parameters following Mutagenesis of Upland Cotton, TAM 94L-25

      Limited genetic diversity could be contributing to the limited genetic gains in upland cotton, Gossypium hirsutum L., fiber lengths and strengths. Smith and Coyle (1997) reported negative associations between many fiber quality traits and the number of fibers per unit surface area of seed (FSSA), the most basic lint yield component. The objective of this study was to determine if mutagenesis could be used to modify the associations of within-boll yield components and fiber quality parameters. TAM 94L-25 (Smith, 2003) (PI 631440) seeds were treated with 3% v/v ethyl methanesulfonate (EMS). (continued)

      Published: June 12, 2015

    • Reena Sellamuthu, Chandrababu Ranganathan and Rachid Serraj
      Mapping QTLs for Reproductive-Stage Drought Resistance Traits using an Advanced Backcross Population in Upland Rice

      The reproductive stage of development is the most drought sensitive, and water deficits at that time can lead to a drastic yield reduction in rice (Oryza sativa L.). Understanding the genetic and physiological bases of yield and yield components under reproductive-stage drought stress will help in the development of resilient cultivars. A population of backcross inbred lines derived from upland cultivars Apo and Moroberekan was used for mapping quantitative trait loci (QTLs) associated with grain yield and other yield-related traits under reproductive stage drought stress and irrigated (nonstress) conditions in the field. Reproductive traits affect grain yield directly and indirectly in both irrigated and drought conditions. (continued)

      Published: June 12, 2015

    • Meixia Li, Zhulin Wang, Ziying Liang, Weinan Shen, Fengli Sun, Yajun Xi and Shudong Liu
      Quantitative Trait Loci Analysis for Kernel-Related Characteristics in Common Wheat ( Triticum aestivum L.)

      This study aimed to identify quantitative trait loci (QTL) controlling wheat (Triticum aestivum L.) 1000-kernel weight (TKW), kernel size (KZ), and kernel shape (KS), using F2 and F2:3 populations derived from a cross between lines ‘0911–46’ and ‘42’. F2:3 grown in two different environments and two parents and F2 plants grown in one environment were phenotyped and genotyped for TKW, KZ including kernel length, kernel width and kernel thickness; and KS (ratios of kernel width/kernel length and kernel thickness/kernel length). Quantitative trait locus investigation was conducted based on a linkage map with 176 simple sequence repeat markers by composite interval mapping. A total of 53 QTLs (logarithm of odds ≥ 3) were identified on 13 chromosomes for six evaluated traits. (continued)

      Published: June 12, 2015

    • Bullo Erena Mamo and Brian J. Steffenson
      Genome-wide Association Mapping of Fusarium Head Blight Resistance and Agromorphological Traits in Barley Landraces from Ethiopia and Eritrea

      Fusarium head blight (FHB), caused primarily by Fusarium graminearum, is an important disease of barley (Hordeum vulgare L.), and other cereals. In barley, the genetic basis of FHB resistance has been intensively studied through linkage mapping that identified several quantitative trait loci (QTL). However, our understanding and application of these QTL in breeding is still limited due to the complex nature and low-to-moderate heritability of FHB resistance. Previous studies used either breeding lines, unimproved varieties, or germplasm selections. (continued)

      Published: June 12, 2015

    • Tadele T. Kumssa, P.S. Baenziger, M.N. Rouse, M. Guttieri, I. Dweikat, G. Brown-Guedira, S. Williamson, R.A. Graybosch, S.N. Wegulo, A.J. Lorenz and J. Poland
      Characterization of Stem Rust Resistance in Wheat Cultivar Gage

      Wheat (Triticum spp.) stem rust, caused by Puccinia graminis f. sp. tritici Eriks. and E. (continued)

      Published: February 3, 2015


    • Lichao Zhai, Ruizhi Xie, Daling Ma, Guangzhou Liu, Pu Wang and Shaokun Li
      Evaluation of Individual Competitiveness and the Relationship Between Competitiveness and Yield in Maize

      Competition plays an important role in ecology and is also a common phenomenon in agricultural production. The objectives of this study were to (i) investigate the yield variability of maize (Zea mays L.) cultivars and populations in mixtures, (ii) evaluate the competitiveness of maize cultivars, and (iii) evaluate the relationship between competitiveness and grain yield. A 2-yr (2012–2013) field experiment was conducted using the de Wit replacement series desSign. Two maize cultivars, Yedan13 (YD13) and Zhongdan909 (ZD909), were grown in seven different YD13/ZD909 combinations (0:6, 1:5, 1:2, 1:1, 2:1, 5:1, and 6:0) with a plant density of 67,500 plants ha−1. (continued)

      Published: July 29, 2015

    • Giulio Testa, Amedeo Reyneri and Massimo Blandino
      Foliar Fungicide Application to Maize: Yield and Grain Hardness Enhancement in Different Environmental Conditions

      The dry-milling industry is becoming an interesting distribution channel for maize (Zea mays L.) growers. Since kernels with high hardness are more suitable for the dry-milling process, it is important to investigate new ways of improving for this qualitative parameter. The aim of the research was to evaluate when a fungicide containing a demethylation inhibitor and a quinone outside inhibitor could be effective in controlling fungal disease, increasing grain yield, and improving kernel hardness. A mixture of azoxystrobin and propiconazole was tested at two locations from 2009 to 2012, with two application timings: the beginning of stem elongation and at tassel emergence. (continued)

      Published: June 12, 2015


    • Thomas R. Sinclair, Anju Manandhar, Nouhoun Belko, Mandeep Riar, Vincent Vadez and Philip A. Roberts
      Variation among Cowpea Genotypes in Sensitivity of Transpiration Rate and Symbiotic Nitrogen Fixation to Soil Drying

      Cowpea (Vigna unguiculata L. Walp.) is often considered a crop species appropriate for drier environments. However, little or no information exists on two key physiological traits for drought conditions: early decrease in transpiration rate in the soil drying cycle and sustained N fixation activity under low soil-water conditions. In this study, the responses of these two traits to soil drying were compared among 10 genotypes. (continued)

      Published: July 17, 2015

    • Bablu Sharma, Glen L. Ritchie and Nithya Rajan
      Near-Remote Green: Red Perpendicular Vegetation Index Ground Cover Fraction Estimation in Cotton

      Ground cover fraction (GCF) can be used as a proxy for leaf area index, plant radiation capture, and plant canopy characteristics in cotton (Gossypium hirsutum L.). One method of imagery-based GCF estimation is to separate plant pixels from soil pixels based on intensity of reflected green and red radiation. However, this method can be time-consuming, may be subject to bias, and is limited by image resolution. We examine a simple, image-based measure of GCF that provides a rapid measurement of crop growth based on the concept of the perpendicular vegetation index (PVI) but using two visible camera channels. (continued)

      Published: June 12, 2015

    • S. L. Kandel, N. Herschberger, S.H. Kim and S. L. Doty
      Diazotrophic Endophytes of Poplar and Willow for Growth Promotion of Rice Plants in Nitrogen-Limited Conditions

      Rice (Oryza sativa L.) is one of the most important staple food crops. Its cultivation requires a relatively high input of N fertilizers; however, rice plants do not absorb a significant proportion of added fertilizers, resulting in soil and water pollution. The use of diazotrophic (N-fixing) endophytes can provide benefits for rice cultivation by reducing the demand of N fertilizers. Diazotrophic endophytes from the early successional plant species poplar (Populus trichocarpa Torr. (continued)

      Published: June 12, 2015

    • S. Liu, M. Remley, F. M. Bourland, R. L. Nichols, W. E. Stevens, A. Phillips Jones and F. B. Fritschi
      Early Vigor of Advanced Breeding Lines and Modern Cotton Cultivars

      Stand establishment and early vigor are critical to the successful production of cotton (Gossypium hirsutum L.). Rapid early growth could provide significant advantages to young plants relative to diseases, insects, and weeds. The objectives of this research were to identify traits that contribute to differences in early growth, characterize genotypic variation in early vigor among modern cultivars and advanced breeding lines, and determine the effect of the seed production environment on early vigor. Early growth of 10 genotypes from private companies and 18 unreleased breeding lines was compared through measurements of leaf area and biomass under field conditions in 2 yr. (continued)

      Published: June 12, 2015


    • Miguel S. Castillo, Lynn E. Sollenberger, M. Kimberly Mullenix, Ann R. Blount, Mary J. Williams and Cheryl L. Mackowiak
      Grazing Management Affects Establishment Performance of Rhizoma Peanut Strip Planted into Bahiagrass Pasture

      Establishing rhizoma peanut (Arachis glabrata Benth.; RP) in strips into existing bahiagrass (Paspalum notatum Flüggé) pastures has potential to increase forage nutritive value, decrease N fertilizer use, and improve N cycling. Grazing the grass–legume mixture in the year after planting may be possible, but appropriate grazing management strategies have not been defined. The objectives were to determine (i) the effect of year-after-planting (Y2) grazing management on ‘Florigraze’ RP performance when strip planted in bahiagrass swards, and (ii) the interaction of Y2 defoliation strategies with those imposed in the year of planting (Y1). Treatments were the factorial combinations of four Y1 defoliation strategies (no defoliation, hay production, simulated continuous stocking, and rotational stocking every 28 d) and three Y2 grazing frequencies (simulated continuous, 28 d, and 42 d to a 15-cm bahiagrass stubble height). (continued)

      Published: June 26, 2015

    • Michael D. Peel, Corey V. Ransom, Ivan W. Mott and Blair L. Waldron
      Natural Glyphosate Tolerance in Sweetvetch Hedysarum boreale

      Sweetvetch (Hedysarum boreale Nutt.) is purported to tolerate glyphosate [N-(phosphonomethyl) glycine]. Eight rates of glyphosate were tested for their effect on biomass (BM) and survival of seedlings and mature plants. Rates were 0, 210, 420, 841, 1681, 3363, 6725, and 13,450 g a.e. ha–1. (continued)

      Published: June 26, 2015


    • Sheuli Roy, Tirthartha Chattopadhyay and Mrinal K. Maiti
      Overexpression of Rice OsGAI in Rice and Tobacco Modulates Gibberellic Acid-Dependent Responses

      Gibberellin, or gibberellic acid (GA), is a crucial phytohormone for its role in overall plant growth and development, particularly in the regulation of plant height. Among the GA-signaling mutants, the gai (GA insensitive) gene has been well studied in Arabidopsis [Arabidopsis thaliana (L.) Heynh.] system. The wild-type GAI, being a DELLA-family protein, acts as a nuclear-localized GA-signaling repressor that restrains the expression of other genes associated with GA-induced growth processes. Here we document alteration in GA-dependent multiple responses obtained through overexpression and expression of the rice (Oryza sativa L.) wild-type GAI (OsGAI) gene in the endogenous (rice) and heterologous (tobacco [Nicotiana tabacum L.]) plant systems, respectively. (continued)

      Published: June 26, 2015

    • Muluneh Tamiru, Shinsuke Yamanaka, Chikako Mitsuoka, Pachakkil Babil, Hiroko Takagi, Antonio Lopez-Montes, Alieu Sartie, Robert Asiedu and Ryohei Terauchi
      Development of Genomic Simple Sequence Repeat Markers for Yam

      Yam (Dioscorea spp.) is a major staple crop widely cultivated for its starchy tubers. To date, very few marker resources are publicly available as tools for genetic and genomic studies of this economically important crop. In this study, 90 simple sequence repeat (SSR) markers were developed from an enriched genomic library of yellow Guinea yam (D. cayenensis Lam.). (continued)

      Published: June 26, 2015

    • Hao Chen, Xiao J. Dai and Zhan Y. Gu
      OsbZIP33 is an ABA-Dependent Enhancer of Drought Tolerance in Rice

      The grain yield of crops has been seriously decreased by abiotic stresses all over the world. Identification of crop stress-resistant genes used in molecular breeding is particularly urgent at this time. Here, we characterized the function of a rice (Oryza sativa L.) basic leucine zipper (bZIP) transcription factor, OsbZIP33, under drought stress. Expression of OsbZIP33 was dramatically induced under drought, high salinity, H2O2 and high temperature stresses. (continued)

      Published: June 12, 2015

    • Yanhua Yang, Li Dai, Keming Zhu, Hengchuan Xia, Liang Chen, Hailong Liu and Keping Chen
      Foreign Protein Detection in Transgenic Rice Revealed by Comparative Proteomic Analysis

      To investigate whether the foreign protein in transgenic rice (Oryza sativa L.) can be detected and then characterize the different proteins between transgenic rice and nontransgenic rice, we employed proteomic tools including two-dimensional electrophoresis (2-DE) and mass spectrometry (MS) to globally identify different proteins between Bt-‘Minghui 63’ (MH63) (with the fused Cry1Ab–Cry1Ac gene) and its nontransgenic control MH63. In all, 37 statistically different proteins between Bt-MH63 and MH63 were successfully identified, including six unique proteins in Bt-MH63. Gene ontology analysis showed that these six unique proteins were mainly involved in metabolic, catalytic, binding, and antioxidant process. Among these six unique proteins, two non-rice source proteins, phosphinothricin-N-acetyltransferase, were only expressed in germinating seed and seedling of Bt-MH63, but not in MH63, which were further confirmed by matrix-assisted laser desorption–ionization time of flight (MALDI-TOF) MS–MS analysis. (continued)

      Published: July 2, 2015

    • Helder Anderson P. Da Silva, Sarah Muniz Nardeli, Marcio Alves-Ferreira and Jean Luiz Simões-Araújo
      Evaluation of Reference Genes for RT-qPCR Normalization in Cowpea under Drought Stress during Biological Nitrogen Fixation

      Reverse transcription–quantitative polymerase chain reaction (RT-qPCR) has emerged as an important technique for gene-expression analysis. However, for accurate and reliable results, the data normalization using appropriated reference genes is critical, and a systematic validation of reference genes in cowpea (Vigna unguiculata L. Walp), a high stress-tolerant leguminous, has not been performed. To provide suitable reference genes in this strategic leguminous species under drought stress, we evaluated the expression stability of eight candidate genes using geNorm and NormFinder algorithms. (continued)

      Published: June 12, 2015


    • Engin Yol, Ramazan Toker, Muharrem Golukcu and Bulent Uzun
      Oil Content and Fatty Acid Characteristics in Mediterranean Sesame Core Collection

      The Mediterranean sesame core collection is a valuable genetic resource for the development of seed quality and quantity. To better characterize and exploit the core collection, this study investigated the oil and fatty acid composition of seeds in the collection. Oil content, determined by a Soxhlet apparatus, varied from 32.3 to 57.3%, with a mean of 46.6%. Oil yield varied greatly among the accessions, with the highest oil yield being 891.1 kg ha−1. (continued)

      Published: June 26, 2015

    • Karen A. Cichy, Timothy G. Porch, James S. Beaver, Perry Cregan, Deidre Fourie, Raymond P. Glahn, Michael A. Grusak, Kelvin Kamfwa, Dennis N. Katuuramu, Phil McClean, Eninka Mndolwa, Susan Nchimbi-Msolla, Marcial A. Pastor-Corrales and Phillip N. Miklas
      A Phaseolus vulgaris Diversity Panel for Andean Bean Improvement

      Dry beans (Phaseolus vulgaris L.) of the Andean gene pool, including red mottled, kidney, cranberry, and yellow seed types are important in Africa and the Americas. Andean dry bean breeding gains have lagged behind those of Mesoamerican beans. This difference may result from a narrower genetic base in the Andean gene pool and reduced breeding efforts. The objective of this research was to establish, genotype, and phenotype a panel of bean germplasm to be used for Andean dry bean breeding. (continued)

      Published: June 26, 2015

    • Donna K. Harris, Mandy D. Kendrick, Zachary R. King, Kerry F. Pedley, David R. Walker, Perry B. Cregan, James W. Buck, Daniel V. Phillips, Zenglu Li and H. Roger Boerma
      Identification of Unique Genetic Sources of Soybean Rust Resistance from the USDA Soybean Germplasm Collection

      Soybean [Glycine max (L.) Merr.] rust is caused by the fungal pathogen Phakopsora pachyrhizi. Six rust resistance loci (Rpp1, 2, 3, 4, 5, and 6) have been reported. Crosses were made between 75 resistant plant introductions (PIs) and a susceptible elite line or cultivar. Bulked segregant analysis (BSA) was used to determine if the PI resistance genes mapped to a previously identified locus or to an unreported locus. (continued)

      Published: June 26, 2015

    • Maren Langhof, Doreen Gabriel and Gerhard Rühl
      Combination Approach of Border Rows and Isolation Distance for Securing Coexistence of Non-Genetically Modified and Genetically Modified Maize

      Border rows of non-genetically modified (GM) maize (Zea mays L.) planted at the GM maize field edge are thought to reduce pollen-mediated gene flow since they act as physical barrier and dilute outgoing GM pollen. In a 3-yr field study, we tested the efficacy of a combination of border rows and isolation distance as a coexistence measure for small-structured agricultural landscapes. Field trials consisted of equally sized (0.8 ha) donor and recipient maize fields that were separated by either a 6- or 12-m isolation distance or a combination of isolation distance with 9- or 18-m border rows. Kernel color was used as a marker to quantify gene flow. (continued)

      Published: June 12, 2015

    • J. A. Kolmer
      Leaf Rust Resistance in Wheat Line RL6062 is an Allele at the Lr3 Locus

      RL6062, a ‘Thatcher’ backcross line of wheat (Triticum aestivum L.), has resistance to leaf rust (caused by Puccinia triticina Erikss.) derived from a line of common wheat from Iran. RL6062 has an intermediate infection type (IT) of small to moderate uredinia surrounded by distinct chlorosis. RL6062 was crossed with Thatcher and the F2 seedlings and F3 families segregated for a single leaf rust resistance gene. Bulk segregant analysis of homozygous resistant and homozygous susceptible F3 families using diversity arrays technology (DArT) markers indicated that the leaf rust resistance was on chromosome 6BL. (continued)

      Published: July 2, 2015

    • Jong-Hyun Chae, Bo-Keun Ha, Gyuhwa Chung, Ju-Eun Park, Euiho Park, Jong-Min Ko, J. Grover Shannon, Jong Tae Song and Jeong-Dong Lee
      Identification of Environmentally Stable Wild Soybean Genotypes with High Alpha-Linolenic Acid Concentration

      Increasing alpha-linolenic acid (ALA) in soybean [Glycine max (L.) Merr] seed oil is an important breeding goal in soybean because of its beneficial effects on human health. Seed oil of wild soybeans (G. soja Sieb. & Zucc.) generally has about twice the ALA concentration than seed oil from cultivated soybeans. (continued)

      Published: June 12, 2015

    • Byron L. Burson, K. Renganayaki, Charlie D. Dowling, Lori L. Hinze and Russell W. Jessup
      Genetic Diversity among Pentaploid Buffelgrass Accessions

      Buffelgrass [Pennisetum ciliare (L.) Link (syn. Cenchrus ciliaris L.)], an important pasture and range grass in the arid semi-tropics and tropics, has excellent drought-tolerance but lacks winter hardiness. It is a polymorphic, apomictic species and its most common chromosome number is 2n = 4x = 36. Eighty-six pentaploid (2n = 5x = 45) accessions from South Africa were deposited into the USDA National Germplasm System (NPGS) in 1976 and these were more winter-hardy than all tetraploid accessions. (continued)

      Published: June 12, 2015

    • Rajan Sharma, Hari D. Upadhyaya, Shivali Sharma, Vishal L. Gate and Chandramani Raj
      New Sources of Resistance to Multiple Pathotypes of Sclerospora graminicola in the Pearl Millet Mini Core Germplasm Collection

      Downy mildew (DM), caused by Sclerospora graminicola (Sacc.) Schröt., is a highly destructive and widespread disease in most pearl millet [Pennisetum glaucum (L.) R. Br.] growing areas of Asia and Africa. Breeding for DM resistance continues to be an integral part of genetic improvement of pearl millet at ICRISAT, Patancheru, India. For the identification of new and diverse sources of DM resistance, a pearl millet mini core collection comprising 238 accessions was screened against eight pathotypes (Sg 384, Sg 409, Sg 445, Sg 457, Sg 510, Sg 519, Sg 526, and Sg 542) of S. (continued)

      Published: June 12, 2015


    • Bingru Huang and Yi Xu
      Cellular and Molecular Mechanisms for Elevated CO 2 –Regulation of Plant Growth and Stress Adaptation

      Increases in atmospheric CO2 concentration have exerted significant impacts on plant growth. Numerous studies have reported positive effects of elevated CO2 on plant growth and adaptation to various environmental stresses in many plant species. The mechanisms by which CO2 enrichment regulates plant growth and stress adaptation are not completely understood. There have been some recent exciting advances in elucidating the cellular, metabolic, and molecular basis for increased growth under elevated CO2. (continued)

      Published: June 12, 2015


    • Stuart P. Hardegree, Christina T. Walters, Alex R. Boehm, Peter J. Olsoy, Patrick E. Clark and Frederick B. Pierson
      Hydrothermal Germination Models: Comparison of Two Data-Fitting Approaches with Probit Optimization

      Probit models for estimating hydrothermal germination rate yield model parameters that have been associated with specific physiological processes. The desirability of linking germination response to seed physiology must be weighed against expectations of model fit and the relative accuracy of predicted germination response. Computationally efficient empirical models have been proposed that do not require a priori assumptions about model shape parameters, but the accuracy of these models has not been compared to the more common probit-optimization procedure. Thirteen seedlots, representing six native perennial rangeland grasses and an invasive annual weed, were germinated over the constant temperature range of 3 to 36°C and water potential range of 0 to -2.5 MPa. (continued)

      Published: June 26, 2015


    • David M. Brenner, Jack Dekker, Jarad Niemi and Lisa Pfiffner
      Medical Oxygen Concentrators for Releasing Seed Dormancy

      A new method is demonstrated for using concentrated oxygen (O2 gas) to release seed dormancy. Concentrated O2 gas in air is known to release seed dormancy in some seeds, including some foxtail (Setaria) species. New medical equipment makes O2 gas easier to work with than before, so laboratories working with dormant seeds can now use concentrated O2 gas as a seed treatment on a production basis. Use of medical O2 gas concentrators is simpler and safer than using O2 gas supplied by pressurized gas cylinders. (continued)

      Published: June 26, 2015


    • Claire H. Luby, Jack Kloppenburg, Thomas E. Michaels and Irwin L. Goldman
      Enhancing Freedom to Operate for Plant Breeders and Farmers through Open Source Plant Breeding

      The Open Source Seed Initiative (OSSI) (www.osseeds.org) seeks to address the dramatic transition over the past 100 yr in how plant germplasm is distributed, developed, and released: from a freely available resource primarily located in the public sector to proprietary structures managed largely by the private sector. OSSI was developed by a group of plant breeders, farmers, seed companies, nonprofit organizations, and policymakers with the goal of promoting and maintaining open access to plant genetic resources worldwide. OSSI seeks to provide an alternative to pervasive intellectual property rights agreements that restrict freedom to use plant germplasm through the development and promulgation of a Pledge which is intended both to raise awareness of these issues and to ensure that germplasm can be freely exchanged now and into the future. In this paper we discuss the historical forces and trends that have led to various types of biological and intellectual property protections and how this has potentially limited plant breeders’ “freedom to operate” and farmers’ sovereignty over seed. (continued)

      Published: May 21, 2015


    • Lynn E. Sollenberger
      Challenges, Opportunities, and Applications of Grazing Research

      Grazing experiments provide fundamental information on the biology of grassland ecosystems, enable selection of persistent forage cultivars that support animal production, and develop management guidelines for end users. Challenges to proper conduct of grazing research include achieving meaningful time and spatial scales, difficulty in measurement of key variables, and scarcity of research funding. Opportunities are emerging for grazing research as a result of increasing awareness of grassland multifunctionality, ecosystem services, and environmental impacts. Capitalizing on these opportunities will require increased participation in grazing research by collaborators from a broader range of ecosystem sciences. (continued)

      Published: June 12, 2015


    • Robert L. Kallenbach
      Describing the Dynamic: Measuring and Assessing the Value of Plants in the Pasture

      The dynamic nature of pastures makes them difficult to quantify. Understanding the near-constant change in plant morphology and development in relation to both biotic (grazing, pathogens, and insects) and abiotic (drought, cold, and heat) events provide the scientific basis for optimizing pasture management plans. Challenges include (i) the cost, primarily for skilled labor, to measure these parameters and (ii) having a scientific team large enough and diverse enough to analyze and interpret the data. New technologies offer opportunities to inexpensively measure pasture growth dynamics. (continued)

      Published: June 26, 2015


    • Eric J. Koeritz, Eric Watkins and Nancy J. Ehlke
      Seeding Rate, Row Spacing, and Nitrogen Rate Effects on Perennial Ryegrass Seed Production

      Seeding rates (SRs) and row-spacing widths (RSWs) in perennial ryegrass (Lolium perenne L.) seed production are variable and the impacts of these factors on perennial ryegrass seed yield and plant growth characteristics are not well characterized. Experiments were conducted during 2010 and 2011 in first-year seed production fields near Roseau and Roosevelt, MN, where five SRs (1.3, 2.6, 5.2, 7.8, and 10.4 kg pure live seed [PLS] ha−1), three RSWs (10, 20, and 30 cm), and three N rates (67, 112, and 157 kg N ha−1) were evaluated in a split-split plot design under nonirrigated conditions. The 30-cm RSW resulted in 45% greater stem rust incidence, 8% fewer fertile tillers, and up to 2% greater 1000-seed weight (TSW) vs. the 10-cm RSW. (continued)

      Published: July 29, 2015

    • K. W. Peterson, D. J. Bremer and J. D. Fry
      Evaluation of Atmometers within Urban Home Lawn Microclimates

      An atmometer is an inexpensive tool used to measure evapotranspiration (ET) in situ. The effects of microclimates associated with urban lawns on the performance of atmometers are not well documented. Our objective was to compare ET estimates between atmometers and the FAO-56 Penman–Monteith equation (PMET, FAO56-PM), including within urban lawns. The study was conducted in six lawns in 2010 and one in 2011 in Manhattan, KS, and four lawns in Wichita, KS, in 2011. (continued)

      Published: July 17, 2015

    • Rashmi Singh, Sudeep S. Sidhu and Patrick E. McCullough
      Physiological Basis for Triazine Herbicide Tolerance in Bermudagrass, Seashore Paspalum, and Zoysiagrass

      Atrazine and simazine control weeds in warm-season turfgrasses, but excessive injury limits applications to sensitive species. The objective of this research was to evaluate the physiological basis for differential tolerances of bermudagrass (Cynodon dactylon (L.) Pers.), seashore paspalum (Paspalum vaginatum Sw.), and zoysiagrass (Zoysia japonica Steud.) to atrazine and simazine. In greenhouse experiments, hierarchical shoot mass reductions from the nontreated by species were: seashore paspalum > bermudagrass > zoysiagrass for atrazine and seashore paspalum > bermudagrass = zoysiagrass for simazine. Atrazine and simazine treatments to soil only or foliar plus soil reduced shoot mass similarly, averaging 45% from nontreated, while foliar-only treatments reduced shoot mass 22% from the nontreated. (continued)

      Published: July 17, 2015

    • Patrick E. McCullough, Jialin Yu, Donn G. Shilling and Mark A. Czarnota
      Physiological Basis for Glyphosate Tolerance in Hard Fescue and Perennial Ryegrass Cultivars

      Glyphosate effectively controls susceptible biotypes of numerous weed species, but applications are often injurious to turfgrass. ‘Aurora Gold’ hard fescue (Festuca longifolia Thuill.) and ‘JS-501’ perennial ryegrass (Lolium perenne L.) have enhanced tolerance to glyphosate compared with traditional varieties, but the mechanisms that convey tolerance are not well understood. The objectives of this research were to investigate the physiological basis for glyphosate tolerance in Aurora Gold hard fescue and JS-501 perennial ryegrass. In greenhouse experiments, the estimated glyphosate rate required to reduce dry shoot mass 50% from the nontreated shoots at 4 wk after treatment measured >3360, >3360, 1850, and 1310 g acid equivalent (a.e.) ha−1 for Aurora Gold, JS-501, ‘Manhattan V’ perennial ryegrass, and ‘Stonehenge’ hard fescue, respectively. (continued)

      Published: July 17, 2015

    • Teresa Donze, Bimal S. Amaradasa, Carol Caha, Tiffany Heng-Moss and Keenan Amundsen
      Molecular Differentiation of Gender in Buffalograss

      Buffalograss [Buchloë dactyloides (Nutt.) Engelm. syn. Bouteloua dactyloides (Nutt.) Columbus] is a warm-season, stoloniferous, perennial grass species native to the Great Plains of North America. Buffalograss is a dioecious species where structural differences can be observed between inflorescences of male and female plants. (continued)

      Published: June 12, 2015

    • B. Shaun Bushman, Scott E. Warnke, Keenan L. Amundsen, Kathleen M. Combs and Paul G. Johnson
      Molecular Markers Highlight Variation within and among Kentucky Bluegrass Varieties and Accessions

      Assessing relationships among germplasm and cultivars of Kentucky bluegrass (Poa pratensis L.) is limited to field evaluations or a small set of molecular markers. To improve the efficiency of characterizing Kentucky bluegrass cultivars and germplasm, this study was designed to develop a larger set of robust molecular makers and a concise panel of cultivars to assess relationships of Kentucky bluegrass. An extensive library of simple sequence repeat markers was developed and used to assess relationships among and within 24 cultivars and accessions. Plants generally grouped as cultivars in cluster analysis, but molecular outlying plants and phenotypic off-type plants were found in 15 of the entries. (continued)

      Published: February 7, 2014

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