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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. 57(3)



  • BIOMEDICAL, HEALTH BENEFICIAL, AND NUTRITIONALLY ENHANCED PLANTS—NOTE

    • Oscar F. Ramos, C. Michael Smith, Allan K. Fritz and Ronald L. Madl
      Bird-Cherry Oat Aphid ( Rhopalosiphum padi ) Feeding Stress Induces Enhanced Levels of Phenolics in Mature Wheat Grains

      Enhancement of naturally occurring phenolic compounds with antioxidant activity in hard red winter wheat (Triticum aestivum L.) is a value addition strategy that can potentially increase the profitability of wheat crops. Phenolics are plant secondary metabolites known to be involved in defense against arthropods and pathogen attack. In this study, the effect of bird-cherry oat aphid (Rhopalosiphum padi L.) feeding in wheat at different phenological stages on phenolic concentration in mature grains was investigated. Aphids were allowed to feed and reproduce for 14 d on wheat plants at the following stages of development: five tillers, 7 or 21 d postanthesis (DPA). (continued)


      doi:10.2135/cropsci2015.08.0476
      Published: May 5, 2017



  • CROP BREEDING & GENETICS

    • Atena Haghighattalab, Jared Crain, Suchismita Mondal, Jessica Rutkoski, Ravi Prakash Singh and Jesse Poland
      Application of Geographically Weighted Regression to Improve Grain Yield Prediction from Unmanned Aerial System Imagery

      Phenological data are important ratings of the in-season growth of crops, though this assessment is generally limited at both spatial and temporal levels during the crop cycle for large breeding nurseries. Unmanned aerial systems (UAS) have the potential to provide high spatial and temporal resolution for phenotyping tens of thousands of small field plots without requiring substantial investments in time, cost, and labor. The objective of this research was to determine whether an accurate remote sensing-based method could be developed to estimate grain yield using aerial imagery in small-plot wheat (Triticum aestivum L.) yield evaluation trials. The UAS consisted of a modified consumer-grade camera mounted on a low-cost unmanned aerial vehicle and was deployed multiple times throughout the growing season in yield trials of advanced breeding lines with irrigated and drought-stressed environments at the International Maize and Wheat Improvement Center in Ciudad Obregon, Sonora, Mexico. (continued)


      doi:10.2135/cropsci2016.12.1016
      Published: June 27, 2017



    • Benjamin Averitt, Chao Shang, Luciana Rosso, Jun Qin, Mengchen Zhang, Katy M. Rainy and Bo Zhang
      Impact of mips1, lpa1 , and lpa2 Alleles for Low Phytic Acid Content on Agronomic, Seed Quality, and Seed Composition Traits of Soybean

      Soybean [Glycine max (L.) Merr] is an important agronomic crop around the world, used largely for animal feed. However, ∼75% of the phosphorus (P) in soybean grain is in the form of phytic acid (PA) or phytate, the cation salt form of PA, which cannot be digested by monogastric and agastric animals including swine, poultry, and aquacultural animals, leading to decreased field efficiency and environmental detriment due to P runoff. Soybean lines have been developed with a reduced PA content using mutant alleles of three genes involved in the PA pathway: either the combination of lpa1 and lpa2 or mips1. However, the relationship among these alleles was unknown. (continued)


      doi:10.2135/cropsci2016.12.1028
      Published: June 16, 2017



    • Andrew R. Jakubowski, Randall D. Jackson and Michael D. Casler
      Can Biomass Yield of Switchgrass be Increased without Increasing Nitrogen Requirements?

      Switchgrass (Panicum virgatum L.) has been identified as a cellulosic bioenergy feedstock crop partly because of its potential to produce high biomass yields on marginal lands. Many breeding programs are focused on increasing biomass yields to improve the economic viability of the crop. However, increasing biomass yields without selecting for reduced biomass nitrogen (N) concentration will result in substantial increases in N removal at harvest. Our objectives were (i) to determine the current trajectory of biomass yield and N removal from breeding programs, (ii) to estimate the reduction in the rate of genetic gain for biomass yield when N concentration was incorporated into a breeding program, and (iii) to estimate the effects reduced N concentration might have on biofuel quality. (continued)


      doi:10.2135/cropsci2017.03.0193
      Published: June 16, 2017



    • Joshua A. Sleper and Rex Bernardo
      Genomewide Selection with Biallelic versus Triallelic Models in Three-Way Maize Populations

      While single nucleotide polymorphism (SNP) markers are typically biallelic, quantitative trait loci (QTL) may have three alleles per locus in three-way populations. Our objective in this study was to determine if multiallelic markers or haplotypes improve the prediction accuracy of genomewide selection in three-way breeding populations. Simulated and empirical maize (Zea mays L.) doubled haploid populations were used to compare a biallelic model, marker interval model (which used adjacent markers to create haplotypes), and allele phasing model (which inferred triallelic markers from parental SNP data). The simulation experiments differed in the number of QTL (10, 40, or 100), heritability (0.30, 0.50, or 0.80), and sizes of allelic effects. (continued)


      doi:10.2135/cropsci2016.12.1001
      Published: June 16, 2017



    • Lorena G. Batista, Rafael S. R. dos Anjos, Nerison L. Poersch, Rafael S. Nalin, Pedro C.S. Carneiro, José E. de S. Carneiro and Marcos D.V. de Resende
      Multigeneration Index in the Selection of Common Bean Inbred Families

      For the common bean (Phaseolus vulgaris L.) crop, most recurrent selection breeding programs use, at the selection stage, inbred families evaluated across two or three generations. This study applied a multigeneration index to produce a best linear unbiased predictor (BLUP) of family effects, aimed at assessing its efficiency in the selection of common bean families. Data from 380 multigenerational families were evaluated across different sowing times and years, and across generations F2:3 and F2:4. The evaluated traits were: plant architecture, yield, and grain appearance. (continued)


      doi:10.2135/cropsci2016.08.0665
      Published: June 16, 2017



    • G.D. Prahalada, G. Ramkumar, Sherry Lou Hechanova, Ricky Vinarao and Kshirod K. Jena
      Exploring Key Blast and Bacterial Blight Resistance Genes in Genetically Diverse Rice Accessions through Molecular and Phenotypic Evaluation

      Blast and bacterial blight (BB) are the most dangerous rice (Oryza sativa L.) diseases that limit rice production significantly. Pib, Piz-t, and Pi9 are reported as key resistance genes for blast whereas Xa21, Xa4, Xa7, and xa13 are considered as important resistance genes for BB. Using gene-specific DNA markers, the presence of these resistance genes was screened in 211 diverse rice accessions originating from 26 countries. In molecular marker analyses, specific amplification patterns for the Pib and Piz-t resistance alleles were observed in 56 and 23 accessions, respectively, whereas the Pi9 resistance allele was not observed at all in these accessions. (continued)


      doi:10.2135/cropsci2016.08.0650
      Published: June 16, 2017



    • J.A. Kolmer
      Genetics of Leaf Rust Resistance in the Hard Red Winter Wheat Cultivars Santa Fe and Duster

      Leaf rust, caused by Puccinia triticina, is a common and important disease of hard red winter wheat (Triticum aeistivum L.) in the Great Plains of the United States. The hard red winter wheat cultivars ‘Santa Fe’ and ‘Duster’ have had effective leaf rust resistance since their release in 2003 and 2006, respectively. The objective of this research was to determine the identity of the leaf rust resistance genes in these cultivars. Both cultivars were vernalized and crossed with the susceptible spring wheat ‘Thatcher’, F1 plants were backcrossed to Thatcher, and 90 backcross (BC) F1 plants from each cross were grown out to develop BC1F2 families. (continued)


      doi:10.2135/cropsci2016.12.1029
      Published: June 16, 2017



    • Adam J. Lukaszewski and Christina Cowger
      Re-Engineering of the Pm21 Transfer from Haynaldia villosa to Bread Wheat by Induced Homoeologous Recombination

      Blumeria graminis f. sp. tritici, the cause of powdery mildew, can generate serious grain yield losses in wheat (Triticum). To expand the range of resistance genes freely available to wheat breeders, a Haynaldia villosa (L.) Schur. (continued)


      doi:10.2135/cropsci2017.03.0192
      Published: June 16, 2017



    • Richard E. Boyles, Brian K. Pfieffer, Elizabeth A. Cooper, Kelsey J. Zielinski, Matthew T. Myers, William L. Rooney and Stephen Kresovich
      Quantitative Trait Loci Mapping of Agronomic and Yield Traits in Two Grain Sorghum Biparental Families

      The animal industry is a major sector of agriculture in the southeastern United States, but a large deficit exists in regional feed grains needed to support the industry. An increase in production of sorghum [Sorghum bicolor (L.) Moench], a water- and nutrient-use-efficient cereal, on marginal lands could lead to an alternative crop option for growers and reduce the current grain deficit. Quantitative trait locus (QTL) mapping of grain yield components in two sorghum biparental recombinant inbred line (RIL) populations was performed to better understand the genetic basis of grain yield and characterize these traits in a marginal environment. A more robust knowledge of the genetics underlying these complex traits could provide insights into molecular breeding strategies that aim to increase genetic gain. (continued)


      doi:10.2135/cropsci2016.12.0988
      Published: June 16, 2017



    • Xingke Fan, Sha Tang, Hui Zhi, Miaomiao He, Wenshuang Ma, Yanchao Jia, Baohua Zhao, Guanqing Jia and Xianmin Diao
      Identification and Fine Mapping of SiDWARF3 ( D3 ), a Pleiotropic Locus Controlling Environment-Independent Dwarfism in Foxtail Millet

      The dwarfing of crop species could enhance lodging resistance in elite cultivars and thus increase cereal grain yields. Foxtail millet [Setaria ema (L.) P. Beauv.] is an ancient grain crop originating from China, and it served as staple food during the development of agricultural-based civilization in South and East Asia, where it is still grown today. Breeding for dwarfism of foxtail millet has great potential in fulfilling the food needs of an increasing world population. (continued)


      doi:10.2135/cropsci2016.11.0952
      Published: June 15, 2017



    • Vilma Kemesyte, Grazina Statkeviciute and Gintaras Brazauskas
      Perennial Ryegrass Yield Performance under Abiotic Stress

      Breeding of perennial ryegrass (Lolium perenne L.) for forage is mainly aimed at increase in herbage yield. However, abiotic stresses such as drought and winterkill threaten persistence and ability to produce stable aerial biomass of the plant. Field experiments, performed under natural conditions, rather than dissection of abiotic stress factors under artificial or semiartificial conditions, offers opportunity to evaluate the effect of complex of abiotic stresses on the plant performance. The aim of this study was to evaluate the relationship between dry matter yield and tolerance to winter kill and drought of perennial ryegrass ecotypes and cultivars differing in their ploidy level during a 2-yr period. (continued)


      doi:10.2135/cropsci2016.10.0864
      Published: June 15, 2017



    • Hussien Alameldin, Ali Izadi-Darbandi, Scott A. Smith, Venkatesh Balan, A. Daniel Jones, Gul Ebru Orhun and Mariam Sticklen
      Metabolic Engineering to Increase the Corn Seed Storage Lipid Quantity and Change Its Compositional Quality

      Given limited global food supplies and the fact that the global population is expected to double by 2050, there is an urgent need for the development of high-calorie foods, including culinary oils. The seeds of oil crops contain high-energy density oil composed of triacylglycerides (TAGs) at up to 80% by dry mass. However, maize (Zea mays L.) seeds are relatively poor in calorie and nutritional values. Therefore, in this report, we address this constraint via metabolic engineering to improve maize seed lipids including TAG and seed TAG nutritional values by overexpression of three major genes, including: (i) the Arabidopsis thaliana (L.) Heynh. (continued)


      doi:10.2135/cropsci2016.06.0513
      Published: June 15, 2017



    • Ntombokulunga W. Mbuma, Marvellous M. Zhou and Rouxlene van der Merwe
      Identifying Elite Families and Determining Optimum Family Selection Rates in Sugarcane Breeding

      Family selection in sugarcane (Saccharum spp. hybrids) increases genetic gains for quantitative traits such as cane yield compared with individual genotype selection because families can be replicated to account for environmental effects. However, optimum family selection rates and trait dynamics among populations are not known. The objectives of this study were to identify elite families for estimated cane yield, determine optimum family selection rates, and identify optimum trait combinations for high yield. (continued)


      doi:10.2135/cropsci2017.01.0011
      Published: June 15, 2017



    • Christian De Guzman, Manuel Esguerra, Steve Linscombe, Greg Berger, Xueyan Sha and James Oard
      Genetic Analysis of Photoperiod/Thermosensitive Male Sterility in Rice under US Environments

      Two-line hybrid rice (Oryza sativa L.) breeding in the United States and China uses photoperiod/thermosensitive genetic male sterility (PTGMS) to produce lines with fertile or sterile pollen, depending on temperature and/or daylength. Although studied in China for >30 yr, genetic analysis of PTGMS in US environments is lacking. We therefore conducted genetic studies of male sterility over 3 yr in five F2 and BC1F2 populations derived from PTGMS line 2008S in Louisiana and Arkansas. Chi-squared analyses in all populations indicated that sterility was controlled at both locations by two or three recessive genes. (continued)


      doi:10.2135/cropsci2016.11.0950
      Published: May 25, 2017



    • Małgorzata Targońska-Karasek, Hanna Bolibok-Brągoszewska and Monika Rakoczy-Trojanowska
      DArTseq Genotyping Reveals High Genetic Diversity of Polish Rye Inbred Lines

      The assessment of genetic diversity in available germplasm is crucial for improvement. In rye (Secale cereale L.) breeding programs, the knowledge of genetic variation on molecular level could be helpful in selection of appropriate components for crossing. The aim of this study was to assess genetic diversity of 150 Polish rye inbred lines with the use of diversity arrays technology sequencing (DArTseq) genotyping and the following bioinformatic tools: Bayesian clustering, principal coordinates analysis, and neighbor-joining clustering. Altogether, 14,892 silicoDArT and 5031 single-nucleotide polymorphism (SNP) markers were analyzed. (continued)


      doi:10.2135/cropsci2016.09.0771
      Published: May 25, 2017



    • Joseph G. Robins and Kevin B. Jensen
      Genotype × Environment Interaction Effects of Propagation and Defoliation on Meadow Bromegrass

      Sixty-three meadow bromegrass (Bromus riparius Rehm.) half-sib families were evaluated over 2 yr at Millville, UT, for biomass production and nutritive value. Families were evaluated under either space-plant or sward conditions combined with either grazed or clipped management. The objective of the study was to determine if selection under standard space-plant and clipping practices resulted in the same rank under seeded plots and grazing. Spearman correlation estimates were low among the four environments for the same trait. (continued)


      doi:10.2135/cropsci2017.02.0072
      Published: May 25, 2017



    • Hem S Bhandari, Santosh Nayak, Cheryl O. Dalid and Virginia R. Sykes
      Biomass Yield Heterosis in Lowland Switchgrass

      Biomass yield improvement of switchgrass (Panicum virgatum L.) is critical for its use as a viable bioenergy feedstock. Population improvement through accumulation of favorable genes and exploitation of heterosis are two ways to improve biomass yield. The objective of this study was to assess biomass yield heterosis in biparental crosses between genotypes of lowland switchgrass. Forty-four genotypic crosses between two predominant lowland populations ‘Alamo’ and ‘Kanlow’, along with nine crosses among genotypes of other lowland germplasm, were evaluated in Knoxville and Crossville, TN. (continued)


      doi:10.2135/cropsci2017.02.0080
      Published: May 25, 2017



    • Jill R. Lennon, Matthew Krakowsky, Major Goodman, Sherry Flint-Garcia and Peter J. Balint-Kurti
      Identification of Teosinte Alleles for Resistance to Southern Leaf Blight in Near Isogenic Maize Lines

      Southern leaf blight ([SLB], causal agent Cochliobolus heterostrophus) is an important fungal disease of maize (Zea mays L.). Teosinte (Z. mays ssp. parviglumis), the wild progenitor of maize, offers a novel source of resistance alleles that may have been lost during domestication. (continued)


      doi:10.2135/cropsci2016.12.0979
      Published: May 18, 2017



    • N. Ace Pugh, Raul Rodriguez-Herrera, Robert R. Klein, Patricia E. Klein and William L. Rooney
      Identification of Quantitative Trait Loci for Popping Traits and Kernel Characteristics in Sorghum Grain

      Popped grain sorghum [Sorghum bicolor (L.) Moench] has developed a niche among specialty snack-food consumers. In contrast with popcorn (Zea mays L.), sorghum has not benefitted from persistent selective breeding for popping efficiency and kernel expansion ratio. Although recent studies have already demonstrated that popping characteristics are heritable in sorghum, the discovery of quantitative trait loci (QTL) for these traits could help expedite and streamline the breeding process. To that end, the objective of this study was to identify regions of the sorghum genome associated with kernel popping traits. (continued)


      doi:10.2135/cropsci2017.01.0029
      Published: May 18, 2017



    • Ryoji Takahashi, Fan Yan, Shaokang Di, Yoshinori Murai, Tsukasa Iwashina and Toyoaki Anai
      Genetic and Chemical Analysis of Deep Purple Flower in Soybean

      A soybean [Glycine max (L.) Merr.] mutant line producing deep purple flowers (E013-C-1) was developed from an ethylmethane sulfonate-treated population of the cultivar ‘Bay’, which has purple flowers. Genetic analysis was performed on a cross between ‘E013-C-1’ and the cultivar ‘Clark’ that had purple flowers. F1 plants had purple flowers whereas F2 plants segregated into a 3:1 purple/deep purple ratio. The results suggest that a single gene controls flower color and that purple color is dominant to deep purple. (continued)


      doi:10.2135/cropsci2016.08.0673
      Published: May 18, 2017



    • Mohamed Somo, Seyed Mostafa Pirseyedi, Xiwen Cai and Francois Marais
      Engineered Versions of the Wheat Lr62 Translocation

      Leaf rust resistance gene Lr62 was transferred from Aegilops neglecta Req. ex Bertol. to chromosome 6A of common wheat (Triticum aestivum L.) in 2008. After homoeologous chromosome pairing induction, smaller translocations that retained Lr62 were derived from it. (continued)


      doi:10.2135/cropsci2016.08.0683
      Published: May 18, 2017



    • Sivakumar Sukumaran, Jose Crossa, Diego Jarquín and Matthew Reynolds
      Pedigree-Based Prediction Models with Genotype × Environment Interaction in Multienvironment Trials of CIMMYT Wheat

      Genotype × environment (G × E) interaction can be studied through multienvironment trials used to select wheat (Triticum aestivum L.) lines. We used spring wheat yield data from 136 international environments to evaluate the predictive ability (PA) of different models in diverse environments by modeling G × E using the pedigree-derived additive relationship matrix (A matrix). These analyses focused on 109 wheat lines from three Wheat Yield Collaboration Yield Trials (WYCYTs) and 168 lines from four Stress Adapted Trait Yield Nurseries (SATYNs) developed by CIMMYT for yield potential conditions and stress conditions, respectively. The main objectives of this study were to use various pedigree-based reaction norm models to predict sites included in each of the three WYCYT nurseries and each of the four SATYN nurseries (individual population) and to predict environments (site-year combinations) when combining the three WYCYT and four SATYN trials (combined population). (continued)


      doi:10.2135/cropsci2016.06.0558
      Published: May 18, 2017



    • Yi Wang, Lance B. Snodgrass, Paul C. Bethke, Alvin J. Bussan, David G. Holm, Richard G. Novy, Mark J. Pavek, Gregory A. Porter, Carl J. Rosen, Vidyasagar Sathuvalli, Asunta L. Thompson, Michael T. Thornton and Jeffrey B. Endelman
      Reliability of Measurement and Genotype × Environment Interaction for Potato Specific Gravity

      Specific gravity (SpGr) is often used to measure the processing quality of potato (Solanum tuberosum L.) tubers for French fries or potato chips because of its strong correlation with dry matter content and ease of measurement. For French fry processing genotypes, the desirable range for mean SpGr is typically 1.080 to 1.095, and a small variance around the mean is essential for product uniformity. Two multi-year, multi-location trials were conducted to investigate the genetics of SpGr in elite russet germplasm. Consistent with earlier studies, the mean SpGr was measured with high repeatability within each environment: the median plot-basis value was 0.83 for a national trial with six locations and 3 yr. (continued)


      doi:10.2135/cropsci2016.12.0976
      Published: May 18, 2017



    • Libin Wei, Hongmei Miao, Fangfang Xu, Jingjing Kong and Haiyang Zhang
      Chinese Sesame Cultivars, DNA Fingerprinting, and Two-dimensional Barcodes Using Single Nucleotide Polymorphisms, Insertions or Deletions, and Simple Sequence Repeat Markers

      Sesame (Sesamum indicum L.) is one of the most important oilseed crops. Accurate and efficient means to identify each variety of sesame are needed for improvement of the sesame production market. In this study, three kinds of molecular markers were used for DNA fingerprinting of 151 sesame cultivars released in China since 1960: single nucleotide polymorphisms (SNPs), insertions or deletions (InDels), and simple sequence repeats (SSRs). The 140 polymorphic markers used (47 SNPs, 47 InDels, and 46 SSRs) revealed a narrow range of genetic variation among the 151 Chinese sesame cultivars. (continued)


      doi:10.2135/cropsci2016.10.0888
      Published: May 11, 2017



    • Mariola Klepadlo, Pengyin Chen, Ainong Shi, R. Esten Mason, Kenneth L. Korth, Vibha Srivastava and Chengjun Wu
      Two Tightly Linked Genes for Soybean Mosaic Virus Resistance in Soybean

      Soybean mosaic virus (SMV), a member of the Potyviridae family, is the most common virus negatively affecting yield and seed quality in soybean [Glycine max (L.) Merr.]. Seven SMV strains, G1 through G7, and three independent SMV resistance genes (R-genes), Rsv1, Rsv3, and Rsv4, have been previously identified. The Rsv1 locus contains at least 10 alleles conferring differential plant reactions to SMV strains, and it was mapped at very complex resistance-gene-rich region. In this study, two alleles of the Rsv1 locus were analyzed by crossing PI 96983 (Rsv1) and cultivar York (Rsv1-y) soybean to evaluate whether Rsv1 and Rsv1-y belong to the same or different but closely linked loci. (continued)


      doi:10.2135/cropsci2016.05.0290
      Published: May 5, 2017



    • Xiaosong Peng, Haohua He, Guoqiang Zhu, Lin Jiang, Changlan Zhu, Qiuying Yu, Jun He, Xianhua Shen, Song Yan and Jianmin Bian
      Identification and Analyses of Chromosome Segments Affecting Heterosis Using Chromosome-Segment Substitution Lines in Rice

      A high level of heterosis exists in intersubspecific crosses between indica and japonica rice (Oryza sativa L.) cultivars, and the exploitation of heterosis has long been considered a promising method of increasing rice yield. To analyze the chromosome segments associated with heterosis for yield-related traits and to dissect the major heterosis quantitative trait loci (QTL) for marker-assisted selection in intersubspecific crosses to improve rice yield, we introduced a set of 37 chromosome-segment substitution lines (CSSLs), each of which carried one or a few chromosome segments of the indica rice cultivar Habataki, in the genetic background of the japonica rice cultivar Sasanishiki. The CSSLs were individually crossed with ‘Changhui T025’ to generate a set of corresponding F1 hybrids (chromosome-segment substitution line hybrids, CSSLHs). These CSSLHs were field-tested for nine yield-related traits in two different environments, and 20 heterosis QTL were detected. (continued)


      doi:10.2135/cropsci2016.03.0140
      Published: May 5, 2017



    • Abdullah A. Jaradat
      Phenotypic and Ionome Profiling of Triticum aestivum × Aegilops tauschii Introgression Lines

      Eighty-five single homozygous introgressions of the Aegilops tauschii D genome in the cultivar Chinese Spring hexaploid wheat (Triticum aestivum L.) genetic background were used to study phenotypic and ionome profiles during 2 yr of field experiments. An augmented design with a repeated bread wheat check was implemented to adjust for spatial soil variability. Percent significant pairwise differences between substitution lines ranged from low (e.g., 28.6% for the ionome) to large (e.g., 78.6% for seed area). The large (>60.0%) significant differences between substitution lines in grain crude protein, spike harvest index, and spike fertility index estimates are of value for wheat agronomic improvement. (continued)


      doi:10.2135/cropsci2016.09.0797
      Published: May 5, 2017



  • CROP BREEDING& GENETICS

    • Jianxiong Jiang, Yuefeng Guan, Sheila McCormick, Jack Juvik, Thomas Lubberstedt and Shui-zhang Fei
      Gametophytic Self-Incompatibility Is Operative in Miscanthus sinensis (Poaceae) and Is Affected by Pistil Age

      Miscanthus sinensis Anderss. (Poaceae) has desirable traits for a dedicated biomass crop. An important breeding goal for M. sinensis is to develop F1 hybrid cultivars. (continued)


      doi:10.2135/cropsci2016.11.0932
      Published: May 5, 2017



  • CROP ECOLOGY, MANAGEMENT & QUALITY

    • Zhandong Liu, Anzhen Qin, Jiyang Zhang, Jingsheng Sun, Dongfeng Ning, Ben Zhao, Junfu Xiao, Zugui Liu and Aiwang Duan
      Maize Yield as a Function of Water Availability across Precipitation Years in the North China Plain

      Crop water production functions require precise knowledge of crop productivity across a wide range of soil water availability (WA). Field studies have demonstrated the yield response of maize (Zea mays L.) to WA, but the relationship has not been quantified across various precipitation years in the North China Plain (NCP). This study was conducted to investigate the effects of the simulated interannual variability in precipitation on maize yield in a winter wheat (Triticum aestivum L.) –summer maize double-cropping system in the NCP, in 2014 and 2015. A rainfall simulator system was used to simulate contrasting precipitation years, including wet, normal, normal-dry, and dry years. (continued)


      doi:10.2135/cropsci2016.10.0866
      Published: June 15, 2017



    • Jintao Wang, Ling Tong, Shaozhong Kang, Fusheng Li, Xiaotao Zhang, Risheng Ding, Taisheng Du and Sien Li
      Flowering Characteristics and Yield of Maize Inbreds Grown for Hybrid Seed Production under Deficit Irrigation

      The study of crop response to deficit irrigation is important for reducing agricultural water use in arid areas. Two experiments were conducted in an arid region of northwestern China in 2014 and 2015 to investigate the responses of the flowering characteristics (pollen shed by male inbreds, silk emergence of female inbreds) and yield components of maize (Zea mays L.) inbred lines to deficit irrigation at the vegetative (V) and flowering (F) stages. There were five irrigation treatments in each year, which were combinations of full irrigation (Stage 2), 50% of full irrigation (Stage 1), and no irrigation (Stage 0) at vegetative (V2, V1, V0) and flowering stages (F2, F1, F0). Results showed that kernel number (KN) ear-1 had significant positive correlations with the total number of exposed silks ear-1 (SNX), seed-set capacity (SC), silking rate ear-1 (ke), silking rate of the female population (kf), and total pollen density at ear height (TPD) but that KN ear-1 had a significant negative correlation with the anthesis–silking interval (ASI). (continued)


      doi:10.2135/cropsci2016.10.0868
      Published: June 15, 2017



    • Adam P. Gaspar, Carrie A.M. Laboski, Seth L. Naeve and Shawn P. Conley
      Dry Matter and Nitrogen Uptake, Partitioning, and Removal across a Wide Range of Soybean Seed Yield Levels

      Soybean [Glycine max (L.) Merr.] growers are concerned that soybean yield is restricted by limitations on biological N2 fixation and soil nitrogen (N) mineralization. However, a comprehensive study characterizing actual soybean N requirements across wide-ranging seed yield environments is nonexistent for modern soybean production systems. Using six site-years and eight soybean varieties, plants were sampled at six growth stages and partitioned into their respective plant parts and analyzed. For each kilogram increase in yield, total dry matter accumulation, harvest index, and total N uptake increased by 1.45 kg, 0.0034%, and 0.054 kg, respectively, but all varied by environment at any specific yield level, whereas N removal did not (0.055 kg N kg−1 grain). (continued)


      doi:10.2135/cropsci2016.05.0322
      Published: May 25, 2017



    • Jia Guo, Arvid Boe, Do-Soon Kim and D.K. Lee
      Growth and Development of Two Perennial Grasses in Ambient Light Conditions during their Natural Dormant Period

      Phenological and morphological behaviors under variable temporal and spatial environmental conditions provide essential information for breeding native perennial warm-season grasses for bioenergy and ecosystem goods and services. Among various environmental factors, natural photoperiodic signals can affect both vegetative and reproductive growth of perennial species. In this study, field-collected plants of switchgrass (Panicum virgatum L.) and prairie cordgrass (Spartina pectinata Link) were subjected to ambient photoperiods of either increasing or decreasing daylength during the dormant period of their normal growth cycles in a temperature-controlled greenhouse. Upland switchgrass reacted to a short-day treatment (decreasing or increasing daylength <12 h) with a less synchronized dormancy-breaking pattern than prairie cordgrass. (continued)


      doi:10.2135/cropsci2016.09.0823
      Published: May 25, 2017



    • Adam P. Gaspar, Carrie A.M. Laboski, Seth L. Naeve and Shawn P. Conley
      Phosphorus and Potassium Uptake, Partitioning, and Removal across a Wide Range of Soybean Seed Yield Levels

      Maintenance of adequate soil phosphorus (P) and potassium (K) levels is critical for profitable soybean [Glycine max (L.) Merr.] production. To accomplish this, precise knowledge of soybean P and K uptake, utilization, and removal is critical, yet a comprehensive study characterizing these requirements across wide-ranging seed yield environments is nonexistent for modern soybean production systems. Using six site-years and eight soybean varieties, plants were sampled at six growth stages , partitioned into their respective plant parts, and analyzed. Distinctly different uptake patterns and rates were found between P and K, where soybean accumulated greater relative amounts of K by R1 and 91 to 100% of its season-long K total by R5.5, compared with only 68 to 77% of its season-long P total. (continued)


      doi:10.2135/cropsci2016.05.0378
      Published: May 18, 2017



    • Adam P. Gaspar, Daren S. Mueller, Kiersten A. Wise, Martin I. Chilvers, Albert U. Tenuta and Shawn P. Conley
      Response of Broad-Spectrum and Target-Specific Seed Treatments and Seeding Rate on Soybean Seed Yield, Profitability, and Economic Risk

      Seed-applied fungicides and insecticides have become common components in modern soybean [Glycine max (L.) Merr.] production for their broad-spectrum activity. However, adding a target-specific seed treatment (fluopyram) to these seed treatment packages in light of increased costs and declining grain sale prices has not been evaluated. Reducing seeding rates (SRs) is possibly one avenue to maximize the economic benefit of seed treatments. Three seed treatments and six SRs were evaluated to determine yield, profitability, and economic risk benefits across 26 environments. (continued)


      doi:10.2135/cropsci2016.11.0967
      Published: May 18, 2017



    • Zhi Dou, She Tang, Ganghua Li, Zhenghui Liu, Chengqiang Ding, Lin Chen, Shaohua Wang and Yanfeng Ding
      Application of Nitrogen Fertilizer at Heading Stage Improves Rice Quality under Elevated Temperature during Grain-Filling Stage

      Global warming would deteriorate rice (Oryza sativa L.) quality, especially chalk characteristic. To better cope with the challenges from global warming, the effects of nitrogen (N) fertilizer at heading stage on rice quality under elevated temperature during grain-filling stage were investigated. Four different growth regimes, including no warming without N fertilizer at heading stage (CK), elevated temperature without N fertilizer at heading stage (ET), elevated temperature with N fertilizer at heading stage (ET+N), no warming with N fertilizer at heading stage (CK+N), were conducted. Elevated temperature during grain filling was achieved by a free-air temperature enhancement facility with the increase of 4°C in ET and 3.7°C in ET+N. (continued)


      doi:10.2135/cropsci2016.05.0350
      Published: May 11, 2017



    • Mingya Wang, Longyu Hou, Qiang Zhang, Xiaona Yu, Li Zhao, Jixiao Lu, Peisheng Mao and David B. Hannaway
      Influence of Row Spacing and P and N Applications on Seed Yield Components and Seed Yield of Siberian Wildrye ( Elymus sibiricus L.)

      Siberian wildrye (Elymus sibiricus L.) is a globally important cool-season forage grass for semiarid regions. However, its seed yield is often low or inconsistent. As previous studies examined the effects of row spacing and P and N levels on seed production of Siberian wildrye separately, this study was focused on the combined effects of four row spacings (30, 45, 60, 75 cm), four P application levels (0, 60, 90, 120 kg P ha−1), and four N application levels (0, 30, 60, 90 kg N ha−1). Treatments were established within a split-split-plot factorial arrangement, with main plots arranged in a randomized complete block design with four replicates. (continued)


      doi:10.2135/cropsci2016.08.0713
      Published: May 5, 2017



  • CROP PHYSIOLOGY & METABOLISM

    • Chiharu Sone and Jun-Ichi Sakagami
      Physiological Mechanism of Chlorophyll Breakdown for Leaves under Complete Submergence in Rice

      Submergence-tolerant rice (Oryza sativa L.) cultivars, including FR13A, retain green leaves for a longer duration than susceptible lines during submergence and exhibit prompt readaptation to the aerial environment after desubmergence. This study clarified the physiological mechanism responsible through the chlorophyll breakdown and photodamage in submerged rice leaves, as indicated by decrease in the maximal quantum yield of photosystem II (Fv/Fm). The ethylene-releasing agent ethephon was used to evaluate the effect of ethylene on chlorophyll breakdown and plant growth. FR13A (submergence-tolerant) and IR72442-6B-3-2-1-1 (submergence-susceptible), either treated with ethephon for 3 d before submergence or untreated, were submerged for 14 d. (continued)


      doi:10.2135/cropsci2016.10.0884
      Published: June 16, 2017



    • Dale Loussaert, Jason DeBruin, Pablo San Martin Juan, Jeff Schussler, Ryan Pape, Joshua Clapp, Nicholas Mongar, Timothy Fox, Marc Albertsen, Mary Trimnell, Sarah Collinson and Bo Shen
      Genetic Male Sterility ( Ms44 ) Increases Maize Grain Yield

      During reproductive development in maize (Zea mays L.), the tassel and the ear compete for available nutrients, at the expense of ear development. The objective of this study was to determine if male sterility (MS) genes could be used to reduce the competition between developing reproductive organs and to improve ear and kernel development. Nitrogen (N) budget experiments conducted in the greenhouse revealed that, under N limiting conditions, the tassel continued to accumulate N prior to anthesis while the ear stopped accumulating N. This finding confirmed prioritization of N partitioning to the tassel at the expense of the developing ear during the critical period of kernel set. (continued)


      doi:10.2135/cropsci2016.08.0654
      Published: June 16, 2017



    • P. Yugandhar, N. Veronica, M. Panigrahy, D. Nageswara Rao, D. Subrahmanyam, S. R. Voleti, S. K. Mangrauthia, R. P. Sharma and N. Sarla
      Comparing Hydroponics, Sand, and Soil Medium To Evaluate Contrasting Rice Nagina 22 Mutants for Tolerance to Phosphorus Deficiency

      Soils deficient in P are widespread in major rice (Oryza sativa L.) ecosystems. In view of declining reserves of rock phosphate and the rising costs of P fertilizers, breeding rice varieties tolerant to low P has become important for future food security. Four different methods (hydroponics without sand [H], hydroponics with sand [HS], large pots with soil [PS], and glasses with soil [GS]) were evaluated using rice aus variety Nagina 22 (N22) and its known gain-of-function (gof) and loss-of-function (lof) mutants to screen for low P tolerance in the field. In −P (no addition of NaH2PO4) shoots, dry weight was significantly higher in gof mutant NH787 than in N22 in HS, PS, and GS but not in H, with fold increases of 1.8 in HS, 5.2 in GS, and 9.4 in PS. (continued)


      doi:10.2135/cropsci2016.07.0594
      Published: May 18, 2017



    • Anju Manandhar, Thomas R. Sinclair, Thomas W. Rufty and Michel E. Ghanem
      Leaf Expansion and Transpiration Response to Soil Drying and Recovery among Cowpea Genotypes

      Sensitivity of leaf expansion to water-deficit conditions could have a major influence on C assimilation rate and water loss rate under developing drought conditions. While cowpea (Vigna unguiculata L.) is commonly grown in more arid regions, there is no information on the sensitivity of its leaf expansion with drying soil. Three experiments were undertaken in controlled environments to document leaf expansion during increasing soil drying (11–13 d). Eight cultivars of cowpea were studied. (continued)


      doi:10.2135/cropsci2016.09.0794
      Published: May 18, 2017



    • Cherryl Quinones, Nico Mattes, James Faronilo, Sudhir-Yadav and Krishna S.V. Jagadish
      Drought Stress Reduces Grain Yield by Altering Floral Meristem Development and Sink Size under Dry-Seeded Rice Cultivation

      Water and labor shortages are currently driving the shift from continuously flooded, puddled transplanted rice (Oryza sativa L.) (PTR-cf) to alternative crop establishment practices, such as dry-seeded rice (DSR). To improve water productivity by using DSR, fields are often kept under aerobic conditions. This shift could induce sensitivity to critical developmental processes during the early reproductive stages such as floral meristem (panicle) initiation and growth, when this coincides with water-limited conditions. To study the physiological impact of different establishment methods with different water available conditions, rice cultivar NSICRc 222 was evaluated, under PTR-cf, dry-seeded rice (DSR) with daily irrigation (DSR-d) and DSR with cyclic irrigation whenever soil water tension reached 10 kPa (DSR-10) and 40 kPa (DSR-40). (continued)


      doi:10.2135/cropsci2016.09.0736
      Published: May 18, 2017



    • Tingting Chen, Xia Zhao, Caixia Zhang, Yongjie Yang, Baohua Feng, Xiufu Zhang, Guanfu Fu and Longxing Tao
      Application of Salicylic Acid Improves Filling of Inferior Grains of Rice during Late Maturity under Mild Cold Stress

      Medium- or late-maturing varieties of rice (Oryza sativa L.) that are planted in agroecosystems in the middle and lower reaches of the Yangtze Valley of China always encounter cold stress during the late grain-filling stage. Generally, grain yield and yield components are adversely affected under such circumstances. To alleviate these negative effects, salicylic acid (SA; i.e., SA0 [control, 0 mg L−1], SA100 [100 mg L−1], SA200 [200 mg L−1], SA300 [300 mg L−1], and SA400 [400 mg L−1]) was exogenously sprayed on plants of three rice cultivars at full heading in the field at the experimental base of China National Rice Research Institute (CNRRI) in Fuyang City, China (30°03′ N, 119°57′ E, 11 m asl). The results indicated that the mean grain-filling rate and grain weight of the inferior grains were significantly increased under the SA200 (200 mg L−1) treatment and correspondingly contributed to a grain yield increase of 5.0 to 10.1% in comparison with the control. (continued)


      doi:10.2135/cropsci2016.11.0941
      Published: May 11, 2017



    • Calvin D. Meeks, John L. Snider, Wesley M Porter, George Vellidis, Gary Hawkins and Diane Rowland
      Assessing the Utility of Primed Acclimation for Improving Water Savings in Cotton using a Sensor-Based Irrigation Scheduling System

      This study addressed the potential of reduced prebloom irrigation, referred to as primed acclimation (PA), to increase agricultural water-use efficiency (WUE) using a soil-moisture-based irrigation scheduling system in cotton (Gossypium hirsutum L.). To address this, a study was conducted near Camilla, GA, under a variable-rate, center-pivot irrigation system using a Watermark-based automated soil moisture sensing approach to measure soil water potential (SWP) and impose varying irrigation scheduling treatments during the prebloom stage of development. Early season thresholds were −20 (Treatment 1), −40 (Treatment 2), −70 (Treatment 3), to −100 kPa (Treatment 4) prior to flowering. Reductions in prebloom irrigation of up to 17% were noted in this study for the driest thresholds (−100 kPa) with no reduction in lint yield relative to the −20 and −40 kPa thresholds. (continued)


      doi:10.2135/cropsci2016.10.0907
      Published: May 5, 2017



  • CROP PHYSIOLOGY & METABOLISM—NOTE

    • C. Andy King and Larry C. Purcell
      Evaluation of Methods for Estimating Transpiration Response to Soil Drying for Container-Grown Plants

      Physiological responses in plants to drought at various fractions of transpirable soil water (FTSW) are often presented relative to well-watered controls. Theoretically, this method allows for comparison of sensitivity among genotypes for various physiological processes and across experiments. It can be difficult to accurately estimate FTSW for measurements occurring over a relatively long period of time, such as gravimetric measurement of transpiration. This research evaluated the impact of determining the FTSW threshold at which transpiration begins to decline based on pot weights made at the beginning, ending, or average of daily transpiration periods. (continued)


      doi:10.2135/cropsci2016.12.1000
      Published: April 27, 2017



  • FORAGE & GRAZINGLANDS

    • Lisa L. Baxter, Charles P. West, Jhones O. Sarturi, C. Philip Brown and Paul E. Green
      Stocker Beef Production on Low-Water-Input Systems in Response to Legume Inclusion: II. Water Footprint

      Information on the water footprint of pasture-based beef production is useful for optimizing the allocation of groundwater to crop and livestock production. The objective of this research was to determine the effect of including legumes on three water footprints of grass-based, beef stocker grazing systems with respect to observed and total (observed plus predicted from hay production) liveweight gain (LWG). Water inputs for the calculations included total or effective rainfall, total or corrected drip irrigation, and water directly consumed by the steers. When including rainfall in the calculation, water footprints were 16.2 to 40.5 vs. (continued)


      doi:10.2135/cropsci2017.05.0289
      Published: June 27, 2017



    • Sarah C. Goslee, Jeffery M. Gonet and R. Howard Skinner
      Freeze Tolerance of Perennial Ryegrass and Implications for Future Species Distribution

      Poor winter hardiness is one of the factors limiting the use of the palatable and productive cool-season forage grass perennial ryegrass (Lolium perenne L) in the northeastern United States. We compared freeze tolerance among seedlings of 13 commercial cultivars of perennial ryegrass in a controlled environment chamber. After a 14-d acclimation period, plants were chilled to −10, −15, or −20°C for 1 h, then gradually warmed. After 36 d, surviving plants were counted then harvested and weighed. (continued)


      doi:10.2135/cropsci2017.02.0135
      Published: June 16, 2017



    • Maria L. Silveira, Joao M. B. Vendramini, Hiran M. S. da Silva, Bernardo M. M. N. Borges, Victor S. Ribeirinho, Julian J. J. Lacerda, Mariana V. Azenha, Pedro R. A. Viegas and Andre D. Aguiar
      Potassium and Phosphorus Fertilization Impacts on Bermudagrass and Limpograss Herbage Accumulation, Nutritive Value, and Persistence

      Despite scientific evidence suggesting that warm-season grasses can respond favorably to K and P fertilization, the increasing costs of fertilizers limit the extent to which these nutrients are used in pastures and hayfields. Two field studies evaluated ‘Jiggs’ bermudagrass [Cynondon dactylon (L.) Pers.] and ‘Floralta’ limpograss (Hemarthria altissima Stapf. and Hubbard) herbage accumulation (HA), nutritive value, and persistence to reduced fertilization strategies during 2012 to 2014. Treatments were allocated in a split-plot design with N (90 or 180 kg N ha−1, bermudagrass study) or harvest frequency (6 vs. (continued)


      doi:10.2135/cropsci2017.03.0147
      Published: June 16, 2017



    • Tiago A. Catuchi, Rogério P. Soratto, Amarildo Francisquini Júnior, Elton A. Aranda, Fernando V. C. Guidorizzi and Carlos S. Tiritan
      Nitrogen Management, Nitrogen Use Efficiency, and Seed Yield and Quality of Creeping Signalgrass

      Nitrogen (N) fertilization management can affect the seed yield and quality of tropical forage grasses. Studies have shown the effect of N rates on tropical grass seed production, but no study has evaluated the effect of application timing of N on the N use efficiency (NUE) and seed yield and quality of creeping signalgrass [Urochloa humidicola (Rendle) Morrone & Zuloaga, syn. Brachiaria humidicola (Rendle) Schweick.]. Field experiments were conducted over two growing seasons in Santo Anastácio, São Paulo, Brazil, to evaluate the influence of N fertilization timing on plant nutrition, herbage mass, N uptake, NUE, and seed yield and quality of creeping signalgrass ‘Llanero’. (continued)


      doi:10.2135/cropsci2017.02.0096
      Published: June 16, 2017



    • Carlos G. S. Pedreira, Valdson J. Silva, Bruno C. Pedreira and Lynn E. Sollenberger
      Herbage Accumulation and Organic Reserves of Palisadegrass in Response to Grazing Management based on Canopy Targets

      Improved grazing management can increase the output of many tropical forage–livestock systems. Adjusted grazing management techniques have been proposed for producers that are willing to exploit the growth potential of available forage resources. The objective of this research was to describe and explain variations in herbage accumulation dynamics and organic reserves of cultivar Xaraés palisadegrass [Brachiaria brizantha (Hochst. ex A. (continued)


      doi:10.2135/cropsci2016.11.0957
      Published: June 16, 2017



    • Albert T. Adjesiwor, M. Anowarul Islam, Valtcho D. Zheljazkov, John P. Ritten and Axel Garcia y Garcia
      Grass-Legume Seed Mass Ratios and Nitrogen Rates Affect Forage Accumulation, Nutritive Value, and Profitability

      Grass-legume mixtures are considered viable alternatives to nitrogen (N)-fertilized grass pastures, but there is a dearth of information on effects of seed mass ratios on productivity and economic returns. We evaluated the effects of grass-legume seed mass ratios and N fertilizer rates on forage accumulation, nutritive value, and profitability. There were 15 treatments arranged in randomized complete blocks with four replicates. The treatments included four species (meadow bromegrass [Bromus biebersteinii Roem. (continued)


      doi:10.2135/cropsci2016.09.0776
      Published: June 16, 2017



    • Lisa L. Baxter, Charles P. West, C. Philip Brown and Paul E. Green
      Stocker Beef Production on Low-Water-Input Systems in Response to Legume Inclusion: I. Forage and Animal Responses

      The imminent decline of the Ogallala Aquifer is encouraging producers in the Southern High Plains (SHP) to seek innovative alternatives to safeguard against dramatic losses of income when pumping capacity is insufficient for irrigated crops. Previous research demonstrated the success of perennial forage grasses in this region, but crude protein (CP) was the limiting factor in improving performance of grazing beef (Bos taurus L.) steers. Possible solutions include integrating legumes into existing warm-season grass pastures and managing small areas of alfalfa (Medicago sativa L.) as a protein bank where irrigation resources can be concentrated. The objective of this research was to compare animal performance in a grass-legume pasture system employing regionally novel forage combinations and grazing techniques to a grass-only system in the water-limited SHP. (continued)


      doi:10.2135/cropsci2017.02.0112
      Published: April 27, 2017



  • GENOMICS, MOLECULAR GENETICS & BIOTECHNOLOGY

    • Karen Harris-Shultz, Xinzhi Ni, Phillip A. Wadl, Xinwang Wang, Hongliang Wang, Fangneng Huang, Kathy Flanders, Nicholas Seiter, David Kerns, Robert Meagher, Qingwu Xue, Dominic Reisig, David Buntin, Hugo E. Cuevas, Michael J. Brewer and Xiangbing Yang
      Microsatellite Markers Reveal a Predominant Sugarcane Aphid (Homoptera: Aphididae) Clone is Found on Sorghum in Seven States and One Territory of the USA

      The sugarcane aphid (Melanaphis sacchari) has become a serious pest causing severe economic losses to sorghum [Sorghum bicolor (L.) Moench] grown in the southern United States. Since its original detection in four states in 2013, M. sacchari on sorghum has now, in 2016, spread to 19 states. The presence of one or multiple genotypes on sorghum in the United States has not yet been established. (continued)


      doi:10.2135/cropsci2016.12.1010
      Published: May 18, 2017



    • Praveena Kanchupati, Yafang Wang, M. Rokebul Anower, Arvid Boe, Tianming Hu and Yajun Wu
      The CBF-Like Gene Family in Alfalfa: Expression Analyses and Identification of Potential Functional Homologs of Arabidopsis CBF3

      We recently identified the alfalfa (Medicago sativa L.) germplasm River Side (RS) and Foster Ranch (FR), both naturally adapted to the Grand River National Grassland environment in South Dakota and showing superior freezing tolerance. To understand the molecular basis of freezing tolerance in RS and FR, we examined expression of the C-repeat binding factor-like (CBFl) genes in alfalfa. Eighteen CBFl genes were identified after examining the genome of Medicago truncatula Gaertn., a close relative of alfalfa. Phylogenetic analysis clustered Medicago CBFs into four subgroups. (continued)


      doi:10.2135/cropsci2016.09.0777
      Published: April 27, 2017



  • INTERNATIONAL TURFGRASS SOCIETY CONFERENCE

    • Kathleen Laura Dodson, Laura Cortese Chaves, James B. Ross and Darrell Tompkins
      Cold Tolerance in Annual Bluegrass Exposed to Anoxic and Hypoxic Conditions

      The use of impermeable tarps has been adopted by golf course superintendents in North America to prevent winter injury due to direct cold temperature exposure and ice damage; however, without ventilation, anoxic conditions can develop under tarps, which can result in extensive damage to annual bluegrass (Poa annua L.) greens. Currently, no information is available to help superintendents determine when or how frequently ventilation under tarps or ice cover is needed for injury prevention. A controlled environment study was performed to determine the effects of anoxic and hypoxic conditions on cold tolerance, represented by the lowest temperature at which 50% survival occurs and nonstructural carbohydrate concentrations of annual bluegrass, and to determine at what gas concentrations managers should ventilate under impermeable tarps. In general, turf exposed to anoxic conditions had reduced cold tolerance at all sampling days, highlighting the importance of avoiding anoxic conditions under impermeable covers. (continued)


      doi:10.2135/cropsci2016.06.0486
      Published: May 25, 2017



    • Charles J. Schmid, Bruce B. Clarke and James A. Murphy
      Anthracnose Severity and Annual Bluegrass Quality as Influenced by Nitrogen Source

      Anthracnose (caused by Colletotrichum cereale Manns sensu lato Crouch, Clarke & Hillman) of annual bluegrass [ABG, Poa annua L. f. reptans (Hausskn.) T. Koyama] turf is a destructive fungal disease that has been shown to be more severe under nitrogen (N) deficiencies. (continued)


      doi:10.2135/cropsci2016.06.0494
      Published: April 20, 2017



    • Stephanie Rossi, Patrick Burgess, David Jespersen and Bingru Huang
      Heat-Induced Leaf Senescence Associated with Chlorophyll Metabolism in Bentgrass Lines Differing in Heat Tolerance

      Leaf senescence is characterized by decreased chlorophyll content in leaves. The objectives of this study were to determine whether heat-induced chlorophyll decline is due to inhibited chlorophyll synthesis or accelerated chlorophyll degradation and to determine whether genetic variations in heat tolerance of bentgrass (Agrostis spp.) species were associated with differential chlorophyll-enzymatic responses to heat stress. Five turfgrass lines, including two transgenic creeping bentgrass (A. stolonifera L.) lines overexpressing isopentenyl transferase (ipt) gene ligated to a senescence-activated promoter (SAG12) or heat shock promoter (HSP18.2) for controlling cytokinin synthesis, two thermal bentgrass (A. (continued)


      doi:10.2135/cropsci2016.06.0542
      Published: April 20, 2017



    • Thomas J. Serensits, Andrew S. McNitt and James T. Brosnan
      Kentucky Bluegrass Divot Resistance as Affected by Cultivar, Trinexapac-ethyl, and Soil Cultivation

      Athletic fields constructed with a high percentage of sand rely on the presence of above- and belowground turfgrass biomass to provide surface stability to athletes. As turfgrass plants are worn away during field use, their stabilizing effect is lost, increasing the potential for divoting. Excessive divoting results in poor footing and may increase the potential for athlete injury. The objectives of this research were to evaluate the effects of two trinexapac-ethyl (TE) treatment regimes and one cultivation procedure on the divot resistance, tiller density, belowground biomass, and turfgrass ground cover of nine Kentucky bluegrass (KBG) (Poa pratensis L.) cultivars under varying levels of simulated traffic. (continued)


      doi:10.2135/cropsci2016.05.0404
      Published: April 20, 2017



    • Norma C. Flor, Philip F. Harmon, Kevin Kenworthy, Richard N. Raid, Russell Nagata and Lawrence E. Datnoff
      Screening St. Augustinegrass Genotypes for Brown Patch and Large Patch Disease Resistance

      Two diseases of St. Augustinegrass (SAG) [Stenotaphrum secundatum (Walt.). Ktze.] are caused by different anastomosis groups (AGs) of Rhizoctonia solani. Brown patch (BP) is a foliar disease of little economic importance, and large patch (LP) causes leaf sheath rot and death of affected turfgrass shoots and stolons. (continued)


      doi:10.2135/cropsci2016.06.0514
      Published: March 27, 2017



    • Timothy D. Colmer and Louise Barton
      A Review of Warm-Season Turfgrass Evapotranspiration, Responses to Deficit Irrigation, and Drought Resistance

      Knowledge of turfgrass evapotranspiration (ETc) and drought resistance can enable water conservation by guiding turfgrass selection for various climates and irrigation scheduling. Turfgrass ETc, crop coefficients (Kc = ETc/ET0, where ET0 is reference evapotranspiration), responses to deficit irrigation, and drought resistance, are reviewed for warm-season species (perennial, sod-forming, C4 grasses). In well-watered conditions, ETc was 2.44 to 10.53 mm d−1 (nine species in six climates during late spring to early autumn) and Kc was 0.34 to 1.27 (seven species in seven climates). Under deficit irrigation, ETc was 2.14 to 5.71 mm d−1 and Kc was 0.52 to 0.94 (seven species in four climates). (continued)


      doi:10.2135/cropsci2016.10.0911
      Published: March 27, 2017



    • Grant L. Thompson and Jenny Kao-Kniffin
      Applying Biodiversity and Ecosystem Function Theory to Turfgrass Management

      In the United States, there is a growing need for turfgrass management practices that protect community and environmental health. The proportion of the developed landscape in the United States covered by turfgrass is significant and, at present, covers at least 1.9% of the total land area and comprises 60% in parts of the country. As urbanization progresses, there is a critical need to re-examine turf management practices that reduce reliance on pesticide and fertilizer inputs while contributing additional beneficial ecosystem services. In this review, we discuss the functional role of turfgrass in urban ecosystems. (continued)


      doi:10.2135/cropsci2016.05.0433
      Published: March 9, 2017



    • Josh A. Honig, Ehud Zelzion, Nicole E. Wagner, Christine Kubik, Vincenzo Averello, Jennifer Vaiciunas, Debashish Bhattacharya, Stacy A. Bonos and William A. Meyer
      Microsatellite Identification in Perennial Ryegrass using Next-Generation Sequencing

      Microsatellite markers are potentially valuable molecular genetic markers for conservation ecology, paternity testing, pedigree reconstruction, population genetics, and linkage mapping. Traditional methods for the development of microsatellite markers can be time-consuming, laborious, and expensive. Next-generation sequencing (NGS) is a more recent and promising approach to microsatellite marker development. Perennial ryegrass (Lolium perenne L.) is an important turfgrass species with a limited set of publicly available microsatellite markers. (continued)


      doi:10.2135/cropsci2016.07.0608
      Published: March 9, 2017



    • Michael Goatley, Kevin Hensler and Shawn Askew
      Cool-Season Turfgrass Germination and Morphological Development Comparisons at Adjusted Osmotic Potentials

      One of the major factors limiting seed germination and seedling development in a low-input, low-maintenance environment is soil moisture availability, yet little is known about the germination response of cool-season turfgrasses to differing osmotic potentials. Controlled-environment studies were conducted to identify germination characteristics of cool-season turfgrass species experiencing water-restricted conditions. At osmotic potentials between 0.0 and −1.6 MPa, perennial ryegrass (Lolium perenne L.) germinated more and had greater radicle lengths than tall fescue [Schedonorus arundinaceus (Schreb.) Dumort], hard fescue (Festuca brevipila Tracey), strong creeping red fescue (F. rubra ssp. (continued)


      doi:10.2135/cropsci2016.06.0482
      Published: March 9, 2017



    • Yuanwen Guo, Yanqi Wu, Justin Q. Moss, Jeffrey A. Anderson and Lan Zhu
      Genetic Variability for Adaptive, Morphological, and Reproductive Traits in Selected Cold-Hardy Germplasm of Common Bermudagrass

      Common bermudagrass [Cynodon dactylon (L.) Pers.] has been widely used as a major warm-season turf and forage grass in the southern United States and in other regions with similar climates around the world. However, it will suffer severe winterkill when grown beyond its region of adaptation. Cold-hardy bermudagrass germplasm have been developed, but its genetic variation for important turfgrass traits remains unknown. The objective of this study was to quantify genetic variability and determine relationships among adaptive, morphological, and reproductive traits in selected cold-hardy common bermudagrass germplasm, including 48 clonal plants from ‘Riviera’ and 50 clonal plants from ‘Yukon’. (continued)


      doi:10.2135/cropsci2016.05.0369
      Published: February 23, 2017



    • Elisha Allan-Perkins, Katie Campbell-Nelson, James T. Popko Jr., Hyunkyu Sang and Geunhwa Jung
      Investigating Selection of Demethylation Inhibitor Fungicide-Insensitive Sclerotinia homoeocarpa Isolates by Boscalid, Flurprimidol, and Paclobutrazol

      Dollar spot, caused by Sclerotinia homoeocarpa F.T. Bennett, is the most economically important disease of golf course turfgrass in the northern United States. Fungicide resistance, especially to demethylation inhibitor (DMI) fungicides, is common for S. homoeocarpa. (continued)


      doi:10.2135/cropsci2016.06.0467
      Published: February 16, 2017



    • Kelly A. Moore, M. Carolina Zuleta, Aaron J. Patton, Brian M. Schwartz, Goretti Aranaz and Susana R. Milla-Lewis
      SSR Allelic Diversity Shifts in Zoysiagrass ( Zoysia spp.) Cultivars Released from 1910 to 2016

      Selection during varietal improvement has been shown to reduce genetic diversity in several different crop species. A reduction in genetic diversity can be detrimental to future breeding efforts and increase susceptibility to biotic stresses. The purpose of this study was to analyze changes in levels of allelic diversity at the gene and population levels in 40 zoysiagrass (Zoysia spp. Willd.) cultivars released between 1910 and 2016 using simple sequence repeat (SSR) markers. (continued)


      doi:10.2135/cropsci2016.06.0452
      Published: February 9, 2017



    • Jing Zhang, Kevin Kenworthy, J. Bryan Unruh, Bishow Poudel, John E. Erickson, Diane Rowland and Jason Kruse
      Physiological Responses to Soil Drying by Warm-Season Turfgrass Species

      A study describing the overall physiological responses to drought and exploring the underlying mechanisms in multiple turfgrass species and genotypes is needed to make improvements in breeding for turfgrass species that are tolerant to water-limiting conditions. The objective of this study was to compare the differential canopy and physiological responses of 14 genotypes of warm-season turfgrasses during a controlled water withdrawal experiment in a greenhouse. Fourteen genotypes from St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntz], Japanese lawngrass (Zoysia japonica Steud.), manillagrass [Zoysia matrella (L.) Merr.], and bermudagrass [Cynodon dactylon (L.) Pers.] were planted in acrylic tubes. (continued)


      doi:10.2135/cropsci2016.05.0316
      Published: February 9, 2017



    • D. S. McCall, X. Zhang, D. G. Sullivan, S. D. Askew and E. H. Ervin
      Enhanced Soil Moisture Assessment using Narrowband Reflectance Vegetation Indices in Creeping Bentgrass

      Turfgrasses are measured aesthetically and by their ability to withstand stressors. Historically, researchers quantified acceptability by visual quality, but inconsistencies necessitate the use of vegetation indices (VIs) as an objective measurement. Indiscernible relationships have been established between turfgrass canopy normalized difference vegetation index (NDVI) and important variables such as soil moisture and leaf chlorophyll content. Alternative and variable–specific indices have been established in cropping systems. (continued)


      doi:10.2135/cropsci2016.06.0471
      Published: February 2, 2017



    • Susana R. Milla-Lewis, Katharine M. Youngs, Consuelo Arrellano and Yasmin J. Cardoza
      Tolerance in St. Augustinegrass Germplasm against Blissus insularis Barber (Hemiptera: Blissidae)

      StAugustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is a widely used lawn grass in the southern United States due to its stoloniferous growth habit and shade tolerance. However, St. Augustinegrass is prone to thatch accumulation, which is conducive to pest problems, with the southern chinch bug (Blissus insularis Barber, SCB) being the most economically important one. Previous work to identify additional sources of SCB resistance reported genotypes with comparatively high numbers of recovered insects but low damage ratings. (continued)


      doi:10.2135/cropsci2016.05.0361
      Published: January 31, 2017



    • Ambika Chandra, Susana Milla-Lewis and Qingyi Yu
      An Overview of Molecular Advances in Zoysiagrass

      Zoysiagrass (Zoysia spp. Willd.) is a perennial warm-season grass adapted to the tropical and southern temperate regions of the world. Species of Zoysia and their interspecific hybrids are recognized for their low cultural requirements and tolerance to a wide array of biotic and abiotic stresses, and are widely used as turfgrass on golf courses, athletic fields, home lawns, and other recreational sites. Plant breeders predominantly use conventional breeding methods involving hybridization and phenotypic selection to make genetic improvements in zoysiagrass. (continued)


      doi:10.2135/cropsci2016.09.0822
      Published: January 31, 2017



    • Michael C. Cox, Sandeep S. Rana, John R. Brewer and Shawn D. Askew
      Goosegrass and Bermudagrass Response to Rates and Tank Mixtures of Topramezone and Triclopyr

      Postemergence herbicide options for mature goosegrass [Eleusine indica (L.) Gaertn.] control in bermudagrass (Cynodon spp. Rich.) turf are lacking. Greenhouse and field trials were conducted to determine the lowest rate at which topramezone, with or without triclopyr, controls goosegrass while maintaining acceptable bermudagrass quality. Greenhouse dose–response studies determined herbicide rates for field trials. (continued)


      doi:10.2135/cropsci2016.05.0439
      Published: January 31, 2017



    • Xunzhong Zhang, Erik H. Ervin, Wenli Wu, Naina Sharma and Alyssa Hamill
      Auxin and Trinexapac-Ethyl Impact on Root Viability and Hormone Metabolism in Creeping Bentgrass under Water Deficit

      Plant growth regulators have been used to improve turfgrass quality and drought tolerance. This study was designed to investigate if foliar application of auxin (indole-3-butyric acid [IBA] at 2 μM) and trinexapac-ethyl (TE, 45 g ha−1), alone or in a combination, improves creeping bentgrass (Agrostis stolonifera L.) root growth and hormone metabolism under water-deficit conditions. The plants were subjected to well-watered or water-deficit stress (40–50% evapotranspiration replacement) conditions for up to 42 d in growth chambers. Water deficit reduced turf quality and net photosynthetic rate (Pn), leaf indole-3-acetic acid (IAA), isopentenyl adenosine (iPA) content, and root viability. (continued)


      doi:10.2135/cropsci2016.05.0434
      Published: January 5, 2017



    • John C. Inguagiato, John E. Kaminski and Timothy T. Lulis
      Effect of Phosphite Rate and Source on Cyanobacteria Colonization of Putting Green Turf

      Cyanobacteria compete with putting green turf, resulting in algal surface crusts that can reduce turf density and quality. The objectives of this study were to assess preventive control of surface cyanobacteria colonization of putting green turf with various phosphite salt sources and formulations. An optimal rate of phosphorous acid to suppress cyanobacteria while minimizing phytotoxicity was also examined. Two field studies were conducted concurrently on an ‘L-93’ creeping bentgrass (Agrostis stolonifera L.) putting green in Storrs, CT, during 2010 and 2011. (continued)


      doi:10.2135/cropsci2016.06.0469
      Published: December 8, 2016



    • Dominic P. Petrella, James D. Metzger, Joshua J. Blakeslee, Edward J. Nangle and David S. Gardner
      Effects of Blue Light and Phenotype on Anthocyanin Accumulation in Accessions and Cultivars of Rough Bluegrass

      Anthocyanins are increasingly being used as natural alternatives in medicinal, food, and industrial products. However, production of anthocyanin extract is often inefficient due to agronomic limitations. On the other hand, the use of turfgrasses for anthocyanin production has been suggested to increase yield twofold. Rough bluegrass (Poa trivialis L.) cultivar ‘Havana’ has been shown to increase anthocyanin content by 117-fold under high light treatment, exhibiting concentrations similar to current anthocyanin sources, and could be an alternative source of anthocyanin. (continued)


      doi:10.2135/cropsci2016.05.0438
      Published: December 2, 2016



    • Nikolaos Ntoulas and Panayiotis A. Nektarios
      Paspalum vaginatum NDVI when Grown on Shallow Green Roof Systems and under Moisture Deficit Conditions

      Management of conventional crops must adapt to the particularities of urban greening techniques, such as green roofing. The aim of the study was to determine seashore paspalum (Paspalum vaginatum Swartz ‘Platinum TE’) response when grown in shallow green roof substrates and under moisture deficit conditions during two summer periods. Treatments included: (i) six different green roof substrates formulated from locally available materials by mixing combinations of sandy loam soil, pumice, perlite, clinoptilolite zeolite, peat, and compost; (ii) two substrate depths (7.5 or 15 cm); and (iii) two irrigation regimes (60 or 100% crop evapotranspiration). Measurements included the determination of substrate moisture content (SMC) and turfgrass normalized difference vegetation index (NDVI). (continued)


      doi:10.2135/cropsci2016.05.0381
      Published: December 2, 2016



    • Qing Mao and David R. Huff
      Characterizing Small RNA Profiles in Allotetraploid Poa annua L. and its Diploid Parents

      A role for small RNAs has been implicated for polyploid evolution. This study was designed to examine the small RNA profiles of Poa annua L. and its diploid parental species. Four profiles, Poa infirma Kunth., Poa supina Schrad., perennial-type Poa annua, and annual-type Poa annua, were analyzed using three biological replicates representing each profile, resulting in a total of 12 libraries, totaling 20,920,659 small (18–30 nucleotide) RNA sequences. (continued)


      doi:10.2135/cropsci2016.06.0462
      Published: December 2, 2016



    • J. Poro, J. S. Ebdon, M. DaCosta and P. W. Brown
      Effects of Mowing Height of Cut and Nitrogen on FAO-56 PM Crop Coefficients for Recreational Turf in the Cool-Humid Region

      Irrigating recreational turf requires ET (evapotranspiration) replacement for water conservation and to sustain optimal leaf growth and turf function under traffic stress. Lysimeter measured actual ET (ETa) can be estimated using a reference crop ET (ETo) from meteorological data adjusted using a crop coefficient (Kc, ETa/ETo) to correct for cultural affects on ETa. Previous studies have not fully investigated the effects of turf culture on Kc. The objective of this research was to develop reliable Kc when ETo is computed using the FAO-56 Penman-Monteith equation, with Kc adjusted according to the effects on ETa of two mowing heights of cut (HOC), two N rates, and three species. (continued)


      doi:10.2135/cropsci2016.05.0363
      Published: November 28, 2016



    • Lisa A. Beirn, James W. Hempfling, Charles J. Schmid, James A. Murphy, Bruce B. Clarke and Jo Anne Crouch
      Differences among Soil-Inhabiting Microbial Communities in Poa annua Turf throughout the Growing Season

      There is increasing interest in understanding plant-associated microbial communities and their impact on plant health. However, research has been limited to major agronomic systems and little is known about the resident microorganisms in economically important specialty crops, such as turfgrass. In this study, we generated a community-wide inventory of the archaea and bacteria that inhabit the soil of Poa annua L. putting green turf at five time points over a 1-yr period. (continued)


      doi:10.2135/cropsci2016.06.0463
      Published: November 28, 2016



    • Francisco J. Flores, Stephen M. Marek, Gabriela Orquera and Nathan R. Walker
      Molecular Identification and Multilocus Phylogeny of Ophiosphaerella Species Associated with Spring Dead Spot of Bermudagrass

      Spring dead spot (SDS) is a devastating disease of bermudagrass [Cynodon dactylon (L.) Pers.], a widely used turfgrass in the transition zone of the United States. The fungi causing SDS have been identified as belonging to three species of the genus Ophiosphaerella based on cultural characters and the morphology of seldom encountered pseudothecial stages. The three species [O. herpotricha (Fr.) Walker, O. (continued)


      doi:10.2135/cropsci2016.05.0437
      Published: November 28, 2016



    • Chunzhen Zhang, Shui-zhang Fei, Peng Liu, Tieming Ji, Jiqing Peng, Ursula Frei and David J. Hannapel
      Transcriptome Changes in Response to Cold Acclimation in Perennial Ryegrass as Revealed by a Cross-Species Microarray Analysis

      Freezing tolerance in perennial ryegrass (Lolium perenne L.) can be dramatically increased by a period of cold acclimation. To understand the mechanisms of cold acclimation and freezing tolerance in L. perenne, a cross-species microarray study was conducted by using total RNA from cold-acclimated and nonacclimated L. perenne to hybridize with Affymetrix Barley1 GeneChips from barley (Hordeum vulgare L.). (continued)


      doi:10.2135/cropsci2016.04.0252
      Published: November 1, 2016



    • Shane Griffith, Nicholas Bero, John Stier, Glen Obear, Sabrina Ruis and Douglas Soldat
      Biosolids as an Alternative Fertilizer for Kentucky Bluegrass Sod Production in Wisconsin

      Land application of biosolids holds the potential to reduce or eliminate the need for synthetic fertilizer applications. The objective of this study was to evaluate the agronomic impacts of using biosolids to produce Kentucky bluegrass (Poa pratensis L.) sod on a silt loam soil in Wisconsin. Anaerobically digested biosolids cake and biosolids cake mixed with sand and sawdust in a 2:1:1 ratio by volume (MetroMixTM) were produced by and obtained from the Madison Metropolitan Sewerage District. Each material was applied at three rates based on their estimated supply of plant-available nitrogen (PAN). (continued)


      doi:10.2135/cropsci2016.05.0367
      Published: October 26, 2016



    • David Jespersen and Bingru Huang
      Effects of Trinexapac-Ethyl and Daconil Action (Acibenzolar- S -Methyl and Chlorothalonil) on Heat and Drought Tolerance of Creeping Bentgrass

      The plant growth regulator trinexapac-ethyl (TE) is known for its effects of suppressing shoot vertical growth. Some fungicides are claimed to promote the physiological health of plants in the absence of diseases. The objective of this study was to determine whether acibenzolar-S-methyl (one of the active ingredients in Daconil Action), TE alone, or the combination of the two may be most effective in promoting creeping bentgrass (Agrostis stolonifera L.) tolerance to heat and drought stress under field conditions. Daconil Action and TE were foliar applied alone or in combination to creeping bentgrass managed under fairway conditions at Rutgers University in 2014 and 2015. (continued)


      doi:10.2135/cropsci2016.05.0377
      Published: October 26, 2016



    • Clint M. Mattox, Alec R. Kowalewski, Brian W. McDonald, John G. Lambrinos, Brian L. Daviscourt and Jay W. Pscheidt
      Nitrogen and Iron Sulfate Affect Microdochium Patch Severity and Turf Quality on Annual Bluegrass Putting Greens

      Microdochium patch is an important turfgrass disease in cool-humid regions and is caused by the pathogen Microdochium nivale (Fries) Samuels & Hallett. Control of the pathogen is necessary to provide acceptable putting-green-quality turf, and fungicide applications are the predominant method of control. Increasing pesticide restrictions have generated interest in alternative management techniques of Microdochium patch. This research evaluated the effects of three nitrogen and five iron sulfate rates on Microdochium patch development on a trafficked, sand-based, annual bluegrass (Poa annua L.) putting green in Corvallis, OR for over 2 yr in the absence of fungicides. (continued)


      doi:10.2135/cropsci2016.02.0123
      Published: October 26, 2016



    • Jialin Yu, Patrick E. McCullough and Mark A. Czarnota
      Selectivity and Fate of Monosodium Methylarsenate in Bermudagrass, Centipedegrass, and Seashore Paspalum

      Centipedegrass [Eremochloa ophiuroides (Munro) Hack.] and seashore paspalum (Paspalum vaginatum Sw.) can be weedy species with other turfgrasses. Monosodium methylarsenate (MSMA) selectively controls these grasses in polyculture with tolerant species such as bermudagrass [Cynodon dactylon (L.) Pers.], but the mechanisms of selectivity are not well understood. The objectives of this research were to investigate the efficacy and behavior of MSMA in bermudagrass, centipedegrass, and seashore paspalum. In greenhouse experiments, the hierarchical rank of injury ranges for species from high to low was centipedegrass > seashore paspalum > bermudagrass. (continued)


      doi:10.2135/cropsci2016.05.0291
      Published: October 26, 2016



  • INTERNATIONAL TURFGRASS SOCIETY SPECIAL SECTION–SHORT COMMUNICATION

    • Trygve S. Aamlid, Agnar Kvalbein and Trond Pettersen
      Evaluation of an Amino-Acid-Based Fertilizer for Grow-In of Creeping Bentgrass Putting Greens

      Turfgrass grow-in on sand-based putting greens usually incurs a high risk for nitrogen (N) leakage. Our objective was to evaluate how substitution of a standard mineral fertilizer with an amino-acid-based fertilizer affects creeping bentgrass (Agrostis stolonifera L.) establishment rate and the concentration of nitrate and total N in drainage water. The experiment was conducted from 19 May to 26 July 2016 in the United States Golf Association green field lysimeter facility at Landvik, Norway. The liquid fertilizers arGrow Turf (70% of N as arginine and 30% as lysine) and Wallco (60% of N as nitrate and 40% as ammonium) were applied at ∼2-wk intervals at the two rates of 1.5 or 3.0 g N m−2 application−1. (continued)


      doi:10.2135/cropsci2016.09.0812
      Published: May 5, 2017



    • Tatsiana Espevig, May Bente Brurberg, Marina Usoltseva, Åslög Dahl, Agnar Kvalbein, Karin Normann and Jo Anne Crouch
      First Report of Dollar Spot Disease, Caused by Sclerotinia Homoeocarpa, of Agrostis Stolonifera in Sweden

      Dollar spot is a destructive and widespread disease affecting most turfgrass species, but until recently it has been absent from the Scandinavian countries of northern Europe. In the fall of 2014, disease symptoms consistent with dollar spot were observed on a golf course fairway in Sweden. A fungus was isolated from symptomatic turf and identified as Sclerotinia homoeocarpa on the basis of ribosomal deoxyribonucleic acid (rDNA) internal transcribed spacer (ITS) sequences, morphology, and culture characteristics. The ITS sequence was identical to isolates of S. (continued)


      doi:10.2135/cropsci2016.10.0835
      Published: April 13, 2017



  • OPINION & POLICY

    • Adrienne C. Shelton and William F. Tracy
      Cultivar Development in the U.S. Public Sector

      Public plant breeders at land grant universities and USDA play a critical role in the development of improved cultivars for farmers in the United States. Over the past 20 yr, a series of reports have documented the decrease in public plant breeding programs, breeder positions, and government financial support. Publically funded programs allow breeders to focus on crop types, geographic locations, and management systems that are not sufficiently profitable to warrant significant investment from private industry. A survey was conducted in 2015 to understand the current state of cultivar development in the U.S. (continued)


      doi:10.2135/cropsci2016.11.0961
      Published: May 18, 2017



  • PLANT GENETIC RESOURCES

    • Carlos I. Arbizu, Pamela M. Tas, Philipp W. Simon and David M. Spooner
      Phylogenetic Prediction of Alternaria Leaf Blight Resistance in Wild and Cultivated Species of Carrots

      Plant scientists make inferences and predictions from phylogenetic trees to solve scientific problems. Crop losses due to disease damage is an important problem that many plant breeders would like to solve, so the ability to predict traits like disease resistance from phylogenetic trees derived from diverse germplasm would be a significant approach to facilitate cultivar improvement. Alternaria leaf blight (ALB) is among the most devastating diseases of carrots (Daucus spp., Apiaceae) worldwide. Thus, new approaches to identify resistant germplasm to this disease are needed. (continued)


      doi:10.2135/cropsci2017.02.0078
      Published: June 27, 2017



    • Charlie D. Dowling, Byron L. Burson and Russell W. Jessup
      Impediments to Hybridization between Napiergrass and different Pennisetum Species

      Napiergrass [Pennisetum purpureum (Schum.) Morrone] is a robust, perennial, warm-season grass that grows throughout the tropical and subtropical regions of the world. Some genotypes have sufficient winter hardiness to survive winters in the Gulf Coast region of the United States. However, germplasm with increased cold tolerance is needed to expand where the grass can be grown as a forage and biofuel crop in the southern United States. A male-sterile napiergrass accession was pollinated with several genotypes of flaccidgrass (P. (continued)


      doi:10.2135/cropsci2016.09.0796
      Published: June 15, 2017



    • Mahbubjon Rahmatov, Mogens S. Hovmøller, Kumarse Nazari, Staffan C. Andersson, Brian J. Steffenson and Eva Johansson
      Seedling and Adult Plant Stripe Rust Resistance in Diverse Wheat–Alien Introgression Lines

      Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici Eriks., is an important foliar disease of wheat (Triticum aestivum L.) worldwide. (continued)


      doi:10.2135/cropsci2016.08.0664
      Published: May 5, 2017



  • RESEARCH

    • Douglas J. Soldat, A. Martin Petrovic, Frank S. Rossi and Jeffrey Barlow
      Nitrate and Ammonium Leaching in Cool-Season Turfgrass as Affected by Temperature and Potential Evapotranspiration

      Nitrogen (N) fertilizer is often added to turfgrass during times of low temperature when soil N mineralization cannot meet plant needs. However, the spring and fall in humid temperate regions often receive more precipitation than evapotranspiration (ET). Excess soluble N in the soil has the potential to be leached into groundwater, especially when groundwater is being recharged. Temperature and ET are hypothesized to influence N uptake independently; however, their individual contributions have not been characterized in turfgrass systems. (continued)


      doi:10.2135/cropsci2016.09.0780
      Published: May 18, 2017



  • REVIEW & INTERPRETATION

    • Lorraine J. Pellack and Douglas L. Karlen
      Iowa Crop Variety Yield Testing: A History and Annotated Bibliography

      Variety testing by U.S. agricultural universities, often in cooperation with experiment stations, and professional crop associations is recognized as an independent, unbiased validation of the viability of commercial crop varieties. In Iowa, variety testing has also been conducted by many private agricultural companies and individual farmers. Records for crop variety evaluations within the state can be traced back to 1871, well before the creation of the Iowa Agricultural Experiment Station in 1888. (continued)


      doi:10.2135/cropsci2017.01.0009
      Published: June 16, 2017



  • SEED PHYSIOLOGY, PRODUCTION & TECHNOLOGY

    • Deke Dong, Longfeng Yan, Rui Dong, Wenxian Liu, Yanrong Wang and Zhipeng Liu
      Evaluation and Analysis of Pod Dehiscence Factors in Shatter-Susceptible and Shatter-Resistant Common Vetch

      Common vetch (Vicia sativa L.) is one of the most important annual forage legumes globally because of its multiple uses and high nutritional content. However, when it matures, the pod dehiscence can cause severe loss of seeds. In this research, we used eight shatter-susceptible vetch accessions and 16 shatter-resistant vetch accessions, which were evaluated and selected from 541 accessions, to compare and analyze the influencing factors related to pod dehiscence. We found that the shatter-susceptible vetches all have abscission layers and that the shatter-resistant vetches all lack abscission layers. (continued)


      doi:10.2135/cropsci2017.03.0191
      Published: June 27, 2017



    • Shirley Lamptey, Lingling Li, Junhong Xie, Renzhi Zhang, Stephen Yeboah and Diogenes L. Antille
      Photosynthetic Response of Maize to Nitrogen Fertilization in the Semiarid Western Loess Plateau of China

      Agriculture in rainfed dry areas is often challenged by inadequate water and nutrient supplies. Responses to these challenges include adequate fertilization, but it is unknown whether different nitrogen (N) rates from that commonly used in the Loess Plateau can alleviate this issue. Field experiments were conducted over three cropping seasons to investigate the effect of different N fertilization levels on soil water dynamics, photosynthetic activity, and grain yield of maize (Zea mays L.) grown in the Western Loess Plateau of China. Fertilizer was applied at planting at rates between 0 and 300 kg N ha−1 at regular increments of 100 kg N ha−1 (referred to as N0 and N300, respectively), and treatments were arranged in a complete randomized block design. (continued)


      doi:10.2135/cropsci2016.12.1021
      Published: June 27, 2017



    • Robert L. Geneve, David F. Hildebrand, Timothy D. Phillips, Maythem AL-Amery and Sharon T. Kester
      Stress Influences Seed Germination in Mucilage-Producing Chia

      Chia (Salvia hispanica L.) is an oil seed crop, with a high ω-3 fatty acid and fiber content, used for food and medicine. Upon imbibition, seeds (nutlets) exude a pectinaceous mucilage. The impact of mucilage on seed germination under different environments is unknown. The objectives of this study were to investigate the potential impact of mucilage on chia seeds germinated under conditions of biotic and abiotic stress. (continued)


      doi:10.2135/cropsci2016.08.0703
      Published: May 18, 2017



  • TURFGRASS SCIENCE

    • A. Dennis Genovesi, Russell W. Jessup, Byron L. Burson, Milt C. Engelke and Ambika Chandra
      Interspecific Hybrids between Pembagrass and St. Augustinegrass

      St. Augustinegrass [Stenotaphrum secundatum (Walt) Kuntze] is an important turfgrass throughout many of the warm, humid regions of the world, including the southeastern United States. Unfortunately, the grass is susceptible to a number of insects, pathogens, and nematodes that adversely reduce its desirability as a turfgrass. Another Stenotaphrum species, pembagrass [S. (continued)


      doi:10.2135/cropsci2016.09.0748
      Published: June 16, 2017



    • Philip Joseph Dwyer, Brandon Horvath, Alexandra Kravchenko and Joseph M. Vargas Jr.
      Predicting Microdochium Patch on Creeping Bentgrass

      Microdochium patch is a major cool-season disease affecting creeping bentgrass (Agrostis stolonifera L.) on golf courses, yet prediction tools are limited to help properly time fungicide applications for control. The objective of this study was to create a predictive model using growth chamber studies to determine the effects of air temperature and leaf wetness duration on the development of Microdochium nivale on creeping bentgrass turf. ‘Penncross’ creeping bentgrass plants were inoculated with leaves infected with M. nivale and maintained in growth chambers while exposed to temperatures of 8, 12, 16, and 20°C at leaf wetness durations of 24, 36, 48, and 60 h. (continued)


      doi:10.2135/cropsci2017.03.0186
      Published: June 16, 2017



    • Xiaowei Pan, Michael D. Richardson, Shiping Deng, Robert J. Kremer, James T. English, Jeanne D. Mihail, Carl E. Sams, Peter C. Scharf, Kristen S. Veum and Xi Xiong
      Effect of Organic Amendment and Cultural Practice on Large Patch Occurrence and Soil Microbial Community

      Organic amendments often stimulate soil microorganisms that result in suppression of soilborne pathogens. However, little information is available about the influences of organic amendments and cultural practices on suppression of Rhizoctonia solani Kühn, which causes large patch on zoysiagrass (Zoysia japonica Steud.). The objective of this study was to evaluate the effect of organic amendments and cultural practices of aerification + topdressing or topdressing on large patch and on changes in soil microbial community composition. A 2-yr field experiment was conducted on a zoysiagrass fairway in Columbia, MO. (continued)


      doi:10.2135/cropsci2016.09.0809
      Published: May 25, 2017



    • Jing Zhang, Brian Glenn, J. Bryan Unruh, Jason Kruse, Kevin Kenworthy, John Erickson, Diane Rowland and Laurie Trenholm
      Comparative Performance and Daily Light Integral Requirements of Warm-Season Turfgrasses in Different Seasons

      Shade or reduced sunlight poses a major challenge for maintaining acceptable turfgrass quality. The quantification of daily light integral (DLI, mol m−2 d−1) requirement could help to identify shade-tolerant germplasm. The objectives of this study were (i) to compare turf performance, and (ii) to determine seasonal DLI requirement of 12 warm-season turfgrass cultivars in response to varying levels of shade. A greenhouse study that included three experiments was conducted in spring (30/20°C), summer (35/25°C), and winter (25/15°C) months. (continued)


      doi:10.2135/cropsci2017.01.0052
      Published: May 18, 2017



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