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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. 56(3)



  • CROP BREEDING & GENETICS

    • Sebastian Miersch, Andreas Gertz, Frank Breuer, Antje Schierholt and Heiko C. Becker
      Influence of the Semi-dwarf Growth Type on Seed Yield and Agronomic Parameters at Low and High Nitrogen Fertilization in Winter Oilseed Rape

      In cereals like wheat (Triticum aestivum L.) or rice (Oryza sativa L.), a short-straw ideotype is characteristic for all modern cultivars, mainly due to the use of genes affecting the dwarf genotype. In oilseed rape (Brassica napus L.), several dwarf mutants are known but so far not widely used. An interesting approach is the production of semi-dwarf hybrids from dwarf and normal-type parents, which might have an increased harvest index (HI) and a higher grain yield, especially when nitrogen (N) availability is restricted. To this point, no systematic comparison using a large number of semi-dwarf and normal-type hybrids has been published. (continued)


      doi:10.2135/cropsci2015.09.0554
      Published: May 27, 2016



    • Stine Petersen, Jeanette H. Lyerly, Peter V. Maloney, Gina Brown-Guedira, Christina Cowger, Jose M. Costa, Yanhong Dong and J. Paul Murphy
      Mapping of Fusarium Head Blight Resistance Quantitative Trait Loci in Winter Wheat Cultivar NC-Neuse

      Fusarium head blight (FHB), primarily caused by Fusarium graminearum, can significantly reduce the grain quality of wheat (Triticum aestivum L.) due to mycotoxin contamination. The objective of this study was to identify quantitative trait loci (QTL) for FHB resistance in the moderately resistant soft red winter wheat cultivar NC-Neuse. A total of 170 recombinant inbred lines (RILs) from a cross between NC-Neuse and the susceptible cultivar AGS 2000 were evaluated in inoculated, mist-irrigated field nurseries. The lines were evaluated for FHB incidence (INC), severity (SEV), Fusarium-damaged kernels (FDK), and deoxynivalenol (DON) content in seven environments between 2011 and 2014. (continued)


      doi:10.2135/cropsci2015.05.0312
      Published: May 27, 2016



    • Liping Dai, Lan Wang, Yujia Leng, Yaolong Yang, Lichao Huang, Long Chen, Yuqiong Wang, Deyong Ren, Jiang Hu, Guanghen Zhang, Li Zhu, Longbiao Guo, Qian Qian and Dali Zeng
      Quantitative Trait Loci Mapping for Appearance Quality in Short-Grain Rice

      Rice (Oryza sativa L.) appearance quality, as defined by both grain shape and lack of chalkiness, are key breeding goals throughout the world’s rice-producing areas. To understand the genetic effects on rice appearance quality, we grew a double-haploid (DH) population derived from the cross between two short-grain rice cultivars, japonica Chunjiang 06 (CJ06) and indica Taichung Native 1 (TN1), in both subtropical Hangzhou and tropical Hainan, China. Transgressive segregation was noted for all measured traits: grain length (GL), grain width (GW), length/width ratio (LW), percentage of kernels with chalk (CK), average chalk size (CS) per kernel, and chalkiness degree (CD, calculated as CK × CS). High positive correlations observed between the chalkiness measures (CK, CS, and CD) with GL and GW indicate that grain shape may have pleiotropic effects on grain chalkiness. (continued)


      doi:10.2135/cropsci2015.07.0404
      Published: May 27, 2016



    • Paul S. Froese, Timothy D. Murray and Arron H. Carter
      Quantitative Cephalosporium Stripe Disease Resistance Mapped in the Wheat Genome

      The soil-borne fungus Cephalosporium gramineum Nisikado and Ikata causes Cephalosporium stripe disease of winter wheat (Triticum aestivum L.), reducing yields significantly in severe cases. There is no known complete resistance to the disease and resistance mapping efforts in wheat have been few. This study was conducted to discover the genomic locations of disease resistance as a preliminary step in the process of molecular marker development. ‘Finch’ and ‘Eltan’ progeny were used for quantitative trait loci (QTL) mapping, and a diversity population of 459 individuals was compiled for the first-ever association mapping of resistance to this disease. (continued)


      doi:10.2135/cropsci2015.09.0568
      Published: May 27, 2016



    • Jode W. Edwards
      Genotype × Environment Interaction for Plant Density Response in Maize ( Zea mays L.)

      Increased adaptation to high plant density has been an important factor in improvements in grain yield in maize (Zea mays L.). Despite extensive public literature on variation and improvement in plant density response among maize varieties, much less public information is available on effects of environment and genotype × environment interactions (G × E) on plant density response for grain yield in maize. The present study was conducted to quantify environment effects and G × E effects on plant density response for maize grain yield. A set of 57 synthetic populations, synthetic × inbred line crosses, and synthetic × synthetic population crosses were evaluated across a five year period including 17 individual location–years. (continued)


      doi:10.2135/cropsci2015.07.0408
      Published: May 27, 2016



    • Daniel J. Robertson, Shien Yang Lee, Margaret Julias and Douglas D. Cook
      Maize Stalk Lodging: Flexural Stiffness Predicts Strength

      Late-season stalk lodging in maize (Zea mays L.) is a major agronomic problem that has far-reaching economic ramifications. More rapid advances in lodging resistance could be achieved through development of selective breeding tools that are not confounded by environmental factors. It was hypothesized that measurements of stalk flexural stiffness (a mechanical measurement inspired by engineering beam theory) would be a stronger predictor of stalk strength than current technologies. Stalk flexural stiffness, rind penetration resistance and stalk bending strength measurements were acquired for five commercial varieties of dent corn grown at five planting densities and two locations. (continued)


      doi:10.2135/cropsci2015.11.0665
      Published: May 27, 2016



    • Bradford D. Hall, Richard Fox, Qu Zhang, Andy Baumgarten, Barry Nelson, Joe Cummings, Ben Drake, Debora Phillips, Kevin Hayes, Mary Beatty, Gina Zastrow-Hayes, Brian Zeka, Jan Hazebroek and Stephen Smith
      Comparison of Genotypic and Expression Data to Determine Distinctness among Inbred Lines of Maize for Granting of Plant Variety Protection

      The Union Internationale pour la Protection des Obtentions Végétales (UPOV) currently relies on morphological characteristics to evaluate distinctness, uniformity, and stability (DUS) as eligibility requirements for the granting of Plant Variety Protection (PVP). We used 10 maize (Zea mays L.) inbred lines, including both unrelated and closely similar pairs, representing three heterotic groups to compare abilities of morphological, ribonucleic acid (RNA) transcription, metabolomic, and single nucleotide polymorphism (SNP) data to distinguish inbred lines. We used the range of variability and robustness as important factors to determine distinguishing power of each methodological approach. Using an index that ranged from 0 to 100 (useless to the perfect ideal), index scores for each methodology were: metabolomics (0), RNA transcription (18.2), morphology (19.6), and SNPs (35.7). (continued)


      doi:10.2135/cropsci2015.03.0185
      Published: May 27, 2016



    • Jennifer J. Trapp, Carlos A. Urrea, Jianfeng Zhou, Lav R. Khot, Sindhu Sankaran and Phillip N. Miklas
      Selective Phenotyping Traits Related to Multiple Stress and Drought Response in Dry Bean

      Abiotic stress tolerance in dry bean (Phaseolus vulgaris L.) is complex. Increased population sizes are contributing to finding QTL conditioning stress response but phenotyping has not kept pace with high throughput genotyping for such studies. Our objectives were to determine effectiveness of 20 most tolerant and 20 most susceptible lines representing phenotypic extremes from a RIL population (‘Buster’ × ‘Roza’ [BR]) to facilitate examination of 19 traits for relevance to stress response and to validate existing QTL conditioning stress response. Using phenotypic extremes tested across multiple trials, eight of the 19 traits were clearly associated with drought stress. (continued)


      doi:10.2135/cropsci2015.05.0281
      Published: May 27, 2016



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

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


      doi:10.2135/cropsci2015.11.0723
      Published: May 27, 2016



    • Juan E. Rosas, Sebastián Martínez, Victoria Bonnecarrère, Fernando Pérez de Vida, Pedro Blanco, Marcos Malosetti, Jean-Luc Jannink and Lucía Gutiérrez
      Comparison of Phenotyping Methods for Resistance to Stem Rot and Aggregated Sheath Spot in Rice

      Stem and sheath diseases caused by Sclerotium oryzae Cattaneo (SCL) and Rhizoctonia oryzae-sativae Sawada Mordue (ROS) can severely reduce rice (Oryza sativa L.) yield and grain quality. Genetic resistance is the best strategy to control them. Phenotypic selection for resistance is hampered due to a heterogeneous distribution of the inoculum in the soil that generates high environmental variability and decreases genetic gain. To have higher selection accuracy it is necessary to develop phenotyping methods with high repeatability and discriminative power. (continued)


      doi:10.2135/cropsci2015.09.0598
      Published: May 27, 2016



    • Paul S. Froese and Arron H. Carter
      Single Nucleotide Polymorphisms in the Wheat Genome Associated with Tolerance of Acidic Soils and Aluminum Toxicity

      Aluminum toxicity is a major yield constraint of wheat (Triticum aestivum L.) in acidic soils, which compose a significant area of Earth’s arable land. There is natural variation in wheat’s Al tolerance and a tolerance gene on chromosome 4D named ALMT1 has been cloned and characterized. Some wheat populations, however, show much variation in acidic field tolerance that is not explained by known major Al tolerance loci. This study was conducted to discover new loci that condition wheat’s tolerance of low soil pH with the ultimate goal of DNA marker development for expedited tolerance breeding and selection. (continued)


      doi:10.2135/cropsci2015.10.0629
      Published: May 27, 2016



    • Silver Tumwegamire, Patrick R. Rubaihayo, Wolfgang J. Grüneberg, Don R. LaBonte, Robert O. M. Mwanga and Regina Kapinga
      Genotype × Environment Interactions for East African Orange-Fleshed Sweetpotato Clones Evaluated across Varying Ecogeographic Conditions in Uganda

      African dry and starchy (DS) orange-fleshed sweetpotato [Ipomoea batatas (L.) Lam] (OFSP) cultivars, distinct from American moist or medium dry and sweet OFSP, have potential to fight vitamin A deficiency (VAD) in the world. This study assessed the genotype × environment (G × E) interactions in multienvironment trials (METs), the genetic correlations for total root yield (TYLD), biomass (BIOM), harvest index (HI), root dry matter (RDM), root starch (RST), root sucrose (RSU), root β-carotene, (RBC), root Fe (RFE), root Zn (RZN), root Ca (RCA), and root Mg (RMG) and the potential contributions of the cultivars to fight VAD and mineral deficiencies. Nine DS OFSP cultivars, (Ejumula, Zambezi, Carrot_C, Kakamega, KMI61, Abuket_1, SPK004/6/6, SPK004/6 and Naspot_5/50) and a medium dry and sweet OFSP cultivar (Resisto) were tested in METs in Uganda. The components were smaller than components for HI, RDM, RST, RSU, and RBC, making it possible to ably select for the traits in the early stages. (continued)


      doi:10.2135/cropsci2015.10.0612
      Published: May 27, 2016



    • Cai Yang, Haitao Zhou, Xiao Shi, Xinjun Zhang, Tianliang Li, Xiaohong Yang, Qian Zhang and Tiegang Lu
      Identification and Analysis of Zbs1, a Dominant Male-Sterile Mutant of Naked Oat ( Avena nuda L.)

      A dominant male-sterile mutant of naked oat (Avena nuda L. ‘Zbs1’) was identified in a plant breeding program for accession A. nuda ‘Pin5’, a widely cultivated naked oat variety in northwest China. No significant differences were detected between Zbs1 and wild-type plants during the vegetative growth stage. (continued)


      doi:10.2135/cropsci2014.07.0525
      Published: May 20, 2016



    • Mahendra Dia, Todd C. Wehner, Richard Hassell, Daniel S. Price, George E. Boyhan, Stephen Olson, Stephen King, Angela R. Davis, Gregory E. Tolla, Jerome Bernier and Benito Juarez
      Value of Locations for Representing Mega-Environments and for Discriminating Yield of Watermelon in the U.S.

      In a crop breeding program, multiple-location trials can be used to define target regions and mega-environments that, in turn, will help the breeder develop stable cultivars. In addition, locations can be chosen that are efficient for distinguishing among cultivars (genotypes) and that are good representatives of the target regions. The objectives of this study were to study mega-environments and identify test locations that were both discriminating and representative of target regions. Watermelon [Citrullus lanatus (Thunb.) Matsum. (continued)


      doi:10.2135/cropsci2015.11.0698
      Published: May 20, 2016



    • Erin M. Arms, Jared K. Lounsbery, Arnold J. Bloom and Dina A. St. Clair
      Complex Relationships among Water Use Efficiency-Related Traits, Yield, and Maturity in Tomato Lines Subjected to Deficit Irrigation in the Field

      Cultivated tomato (Solanum lycopersicum L.) is susceptible to abiotic stresses, including water stress. In contrast, a wild tomato relative, S. habrochaites S. Knapp & D.M. (continued)


      doi:10.2135/cropsci2015.10.0661
      Published: May 13, 2016



    • Jared K. Lounsbery, Erin M. Arms, Arnold J. Bloom and Dina A. St. Clair
      Quantitative Trait Loci for Water-Stress Tolerance Traits Localize on Chromosome 9 of Wild Tomato

      A wild tomato species (Solanum habrochaites S. Knapp & D.M. Spooner) is tolerant to many abiotic stresses, including limited water, and can serve as a valuable genetic resource for breeding cultivated tomato (S. lycopersicum L.). (continued)


      doi:10.2135/cropsci2015.07.0432
      Published: May 13, 2016



    • Whitney M. Jones, C. Wayne Smith and James L. Starr
      Resistance to Rhizoctonia solani and Pythium ultimum in Upland Cotton ( Gossypium hirsutum L.)

      Upland cotton, Gossypium hirsutum L., is grown extensively in the southern United States with an annual farmgate value of $5 billion and an annual national economic impact of over $28 billion. Two seed and seedling disease pathogens, Rhizoctonia solani and Pythium ultimum, are the most significant soilborne pathogens of cotton in the United States. Three germplasm families selected for elevated levels of condensed tannins (HT) along with ‘Tamcot Luxor’, as a resistant control, were evaluated for resistance to R. solani and two HT families were evaluated for resistance to P. (continued)


      doi:10.2135/cropsci2015.12.0767
      Published: May 6, 2016



    • Thaís Furtado Nani, Daniele Laís Pereira, Fausto Souza Sobrinho and Vânia Helena Techio
      Physical Map of Repetitive DNA Sites in Brachiaria spp.: Intravarietal and Interspecific Polymorphisms

      Brachiaria (Trin.) Griseb. is a genus belonging to the Poaceae Barnh. family that aggregates species of forage interest, which have shown different levels of ploidy, intraspecific variability for chromosomal morphology and for number of rDNA sites. This study aimed at characterizing the karyotype of Brachiaria brizantha (Hochst. (continued)


      doi:10.2135/cropsci2015.12.0760
      Published: May 6, 2016



    • Baohua Wang, Xavier Draye, Zhengsheng Zhang, Zhimin Zhuang, O. Lloyd May, Andrew H. Paterson and Peng W. Chee
      Advanced Backcross Quantitative Trait Locus Analysis of Fiber Elongation in a Cross between Gossypium hirsutum and G. mustelinum

      In an effort to explore the secondary gene pool for the enhancement of upland cotton (Gossypium hirsutum L.) germplasm, we developed advanced-generation backcross populations by crossing G. hirsutum (PD94042) and Gossypium mustelinum Miers ex Watt (AD4–8), then backcrossing to the G. hirsutum parent for three cycles. Genome-wide mapping revealed introgressed alleles at an average of 13.8% of loci in each BC3F1 plant, collectively representing G. (continued)


      doi:10.2135/cropsci2015.12.0753
      Published: April 29, 2016



    • Yadi Xing, Dan Du, Yanhua Xiao, Tianquan Zhang, Xinlong Chen, Ping Feng, XianChun Sang, Nan Wang and Guanghua He
      Fine Mapping of a New Lesion Mimic and Early Senescence 2 ( lmes2 ) Mutant in Rice

      A novel lesion mimic and early senescence 2 (lmes2) mutant was identified from Jinhui10, an indica restorer line in rice (Oryza sativa L.), which was treated with ethyl methane sulfonate (EMS). Lmes2 began to develop disease-like lesions on leaves at the seedling stage and aged leaves that had the maximum distribution of such lesions began to senesce. Compared with the wild-type, a low content of chlorophylls was observed, while the proline content increased in proportion to the development of lesion mimics. In addition, the photosynthetic rate and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities fell very significantly, which indicates that lmes2 develops early senescence. (continued)


      doi:10.2135/cropsci2015.09.0541
      Published: April 29, 2016



    • Sivakumar Sukumaran, Xin Li, Xianran Li, Chengsong Zhu, Guihua Bai, Ramasamy Perumal, Mitchell R. Tuinstra, P.V. Vara Prasad, Sharon E. Mitchell, Tesfaye T. Tesso and Jianming Yu
      QTL Mapping for Grain Yield, Flowering Time, and Stay-Green Traits in Sorghum with Genotyping-by-Sequencing Markers

      Molecular breeding can complement traditional breeding approaches to achieve genetic gains in a more efficient way. In the present study, genetic mapping was conducted in a sorghum recombinant inbred line (RIL) population developed from Tx436 (a non-stay-green high food quality inbred) × 00MN7645 (a stay-green high yield inbred) and evaluated in eight environments (location and year combination) in a hybrid background of Tx3042 (a non-stay-green A-line). Phenotyping was conducted for agronomic traits (grain yield and flowering time), physiological traits of stay-green (chlorophyll content [SPAD] and chlorophyll fluorescence [Fv/Fm] measured on the leaves), and green leaf area visual score (GLAVS). This population was genotyped with genotyping-by-sequencing (GBS) technology. (continued)


      doi:10.2135/cropsci2015.02.0097
      Published: April 29, 2016



    • B.T. Campbell, J. Greene, J. Wu and D.C. Jones
      Genetic Variation for Agronomic and Fiber Quality Traits in a Population Derived from High-Quality Cotton Germplasm

      Genetic improvement of fiber quality is necessary to meet the requirements of processors and users of upland cotton (Gossypium hirsutum L.) fiber. To foster genetic improvement of cotton fiber quality, adequate genetic variation for the quantitatively inherited physical properties of cotton is required. Additionally, knowledge of the genetic architecture of fiber quality is needed to design effective breeding strategies to further improve fiber quality. In this study, our objective was to estimate genetic variance components and predict genetic effects for agronomic and fiber quality traits in a population derived from four known genotypic sources of high fiber quality. (continued)


      doi:10.2135/cropsci2015.10.0657
      Published: April 15, 2016



    • Duli Zhao, Vanessa S. Gordon, Jack C. Comstock, Neil C. Glynn and Richard M. Johnson
      Assessment of Sugarcane Yield Potential across Large Numbers of Genotypes using Canopy Reflectance Measurements

      Canopy reflectance indices have been used to monitor plant growth and estimate yields in many field crops. Little is known if canopy reflectance of sugarcane (a complex hybrid of Saccharum spp.) can be used to estimate growth and yield potential across large numbers of genotypes (clones) in the early stages of a breeding program. The objectives of this study were to identify clonal variation in sugarcane canopy reflectance and yield components and to determine if there were any putative relationships between canopy reflectance or reflectance indices and yield variables. In Stage II of the Canal Point sugarcane breeding and cultivar development program (CP program), canopy reflectance data were collected five to six times from each of 156 to 164 randomly selected clones during the growing seasons in 2011 through 2013 using a multispectral radiometer. (continued)


      doi:10.2135/cropsci2015.12.0747
      Published: April 15, 2016



    • Yaqi Wang, Wei Chen, Ye Zhang, Meifeng Liu, Jiejie Kong, Zheping Yu, Ali M. Jaffer, Junyi Gai and Tuanjie Zhao
      Identification of Two Duplicated Loci Controlling a Disease-like Rugose Leaf Phenotype in Soybean

      The disease-like leaf mutant exhibits sensitive symptoms in the absence of pathogens and is an important experimental material for studying leaf development and pathogen resistance mechanisms in plants. We used 60Co γ ray irradiation treatment of a Japanese soybean [Glycine max (L.) Merr.] plant introduction Tamahomore to obtain a new disease-like mutant, designated NT301. The mutant leaves were significantly smaller and thicker than those of the wild-type plant, with a reduction in leaf vein growth and increased growth of leaf mesophyll tissue. The surface of these rugose leaves resembled the symptoms of virus infection. (continued)


      doi:10.2135/cropsci2015.09.0580
      Published: April 15, 2016



    • Vijaya Singh, Chuc T. Nguyen, Zongjian Yang, Scott C. Chapman, Erik J. van Oosterom and Graeme L. Hammer
      Genotypic Differences in Effects of Short Episodes of High-Temperature Stress during Reproductive Development in Sorghum

      Recent studies on sorghum [Sorghum bicolor (L) Moench] showed that episodes of high-temperature stress around anthesis could adversely affect grain yield via effects on pollen germination with varying responses among genotypes. The objectives of this study were to determine the reproductive development phase most sensitive to heat stress and to determine whether genotypic differences in high-temperature tolerance were associated with differences in either cardinal temperatures for pollen germination, the duration of the period of sensitivity to high temperatures, or the extent of the response to high temperature per se. To determine cardinal temperatures, pollen from six genotypes, differing in high-temperature tolerance, was incubated on a gradient plate at temperatures between 10 and 40°C. To identify the critical period of high temperature sensitivity, plants of two genotypes with contrasting high-temperature tolerance were grown under optimum (31 vs. (continued)


      doi:10.2135/cropsci2015.09.0545
      Published: April 15, 2016



    • Alina Liersch, Jan Bocianowski, Henryk Woś, Laurencja Szała, Katarzyna Sosnowska, Teresa Cegielska-Taras, Kamila Nowosad and Iwona Bartkowiak-Broda
      Assessment of Genetic Relationships in Breeding Lines and Cultivars of Brassica napus and Their Implications for Breeding Winter Oilseed Rape

      The level of genetic diversity or similarity between parents has been proposed as a predictor of F1 generation performance and heterosis for seed yield. The objective of this study was to determine the feasibility of using amplified fragment length polymorphism (AFLP) fluorescent-labeled primers to evaluate the genetic relationships between 101 oilseed rape (Brassica napus L.) genotypes to maximize the selection of different parents in a breeding program. The collection of genotypes included 25 cytoplasmic male sterility ogura and 21 restorer lines (Rfo). The set of genotypes was completed with B. (continued)


      doi:10.2135/cropsci2015.08.0530
      Published: April 15, 2016



    • M. Kathryn Turner, Yue Jin, Matthew N. Rouse and James A. Anderson
      Stem Rust Resistance in ‘Jagger’ Winter Wheat

      ‘Jagger’ has been used widely as a parent to develop hard red winter wheat (Triticum aestivum L.) varieties throughout the US southern Great Plains. Jagger has resistance to the stem rust pathogen race TTTTF, which is virulent to many winter wheat cultivars, yet the genetic basis of this resistance was unknown. Marker analysis and resistance to leaf rust and stripe rust demonstrated that Jagger has the 2NS/2AS translocation from T. ventricosum (Tausch) Ces., Pass. (continued)


      doi:10.2135/cropsci2015.11.0683
      Published: April 15, 2016



    • Mahendra Dia, Todd C. Wehner, Richard Hassell, Daniel S. Price, George E. Boyhan, Stephen Olson, Stephen King, Angela R. Davis and Gregory E. Tolla
      Genotype × Environment Interaction and Stability Analysis for Watermelon Fruit Yield in the United States

      One of the major breeding objectives for watermelon (Citrullus lanatus [Thumb.] Matsum & Nakai) is improved fruit yield. High yielding genotypes have been identified, so we measured their stability for fruit yield and yield components over diverse environments. The objectives of this study were to (i) evaluate the yield of watermelon genotypes over years and locations, (ii) identify genotypes with high stability for yield, and (iii) measure the correlations among univariate and multivariate stability statistics. A diverse set of 40 genotypes was evaluated over 3 yr (2009, 2010, and 2011) and eight locations across the southern United States in replicated trials. (continued)


      doi:10.2135/cropsci2015.10.0625
      Published: April 15, 2016



    • Fan Yan, Shaokang Di, Yoshinori Murai, Tsukasa Iwashina, Toyoaki Anai and Ryoji Takahashi
      New Allelic Variant Discovered at Soybean Flower Color Locus W1 Encoding Flavonoid 3′5′-hydroxylase

      A soybean line producing light purple flowers (E023-H-12) was developed from an ethyl methanesulfonate (EMS)-treated population of cultivar Bay. The objective of this study was to investigate the genetic and molecular basis of flower color variation in E023-H-12. Genetic analysis suggested that the W1 gene encoding a flavonoid 3′5′-hydroxylase (F3′5′H) controls light purple flower color. A single plant with purple flowers was generated in an F2 population derived from a cross between E023-H-12 and Clark-w1 with white flowers, probably because of intragenic recombination of the F35H gene. (continued)


      doi:10.2135/cropsci2015.07.0413
      Published: April 15, 2016



    • Xiuting Zheng, Kevin A. Hoegenauer, Jose Quintana, Alois A. Bell, Amanda M. Hulse-Kemp, Robert L. Nichols and David M. Stelly
      SNP-Based MAS in Cotton under Depressed-Recombination for Ren lon –Flanking Recombinants: Results and Inferences on Wide-Cross Breeding Strategies

      Strong resistance to reniform nematode (Rotylenchulus reniformis) was previously introgressed from the F-genome diploid species Gossypium longicalyx (2n = 2x = 26) into Upland cotton (G. hirsutum L., 2n = 4x = 52, 2[AD]1), and attributed to the gene Renlon. Two resistant elite lines were released, but their seedlings are differentially stunted in nematode-infested fields. Here, we report on the development of linked SNPs and their use to disrupt “linkage drag” around Renlon. (continued)


      doi:10.2135/cropsci2015.07.0436
      Published: April 8, 2016



    • Vijay Chaikam, Leocadio Martinez, Albrecht E. Melchinger, Wolfgang Schipprack and Prasanna M. Boddupalli
      Development and Validation of Red Root Marker-Based Haploid Inducers in Maize

      One of the critical limitations for the in vivo production of doubled haploid (DH) lines in maize (Zea mays L.) is the inability to effectively identify haploids in a significant proportion of induction crosses due to the possibility of complete or partial inhibition of the currently used R1-nj (Navajo) color marker. In this study, we demonstrate that the R1-nj marker could result in a high proportion of false positives among the haploids identified, besides being ineffective in germplasm with natural anthocyanin expression in pericarp tissue. To address these limitations, we developed haploid inducer lines with triple anthocyanin color markers, including the expression of anthocyanin coloration in the seedling roots and leaf sheaths, in addition to the Navajo marker on the seed. Although these inducers show acceptable haploid induction rates ranging from 8.6 to 10.2%, they exhibited relatively poor agronomic performance compared with tropicalized haploid inducers within tropical environments. (continued)


      doi:10.2135/cropsci2015.10.0653
      Published: April 8, 2016



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

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


      doi:10.2135/cropsci2015.08.0475
      Published: February 12, 2016



  • CROP ECOLOGY, MANAGEMENT & QUALITY

    • John M. Orlowski, Bryson J. Haverkamp, Randall G. Laurenz, David. A. Marburger, Eric W. Wilson, Shaun N. Casteel, Shawn P. Conley, Seth L. Naeve, Emerson D. Nafziger, Kraig L. Roozeboom, William J. Ross, Kurt D. Thelen and Chad D. Lee
      High-Input Management Systems Effect on Soybean Seed Yield, Yield Components, and Economic Break-Even Probabilities

      Elevated soybean [Glycine max (L.) Merr.] prices have spurred interest in maximizing soybean seed yield and has led growers to increase the number of inputs in their production systems. However, little information exists about the effects of high-input management on soybean yield and profitability. The purpose of this study was to investigate the effects of individual inputs, as well as combinations of inputs marketed to protect or increase soybean seed yield, yield components, and economic break-even probabilities. Studies were established in nine states and three soybean growing regions (North, Central, and South) between 2012 and 2014. (continued)


      doi:10.2135/cropsci2015.10.0620
      Published: May 27, 2016



    • Yonggan Zhao, Huancheng Pang, Jing Wang, Yuyi Li and Yan Li
      Depth of Stover Layer for Salt Management Influences Sunflower Production in Saline Soils

      This study aimed to identify the optimal stover layer depth for resolving soil water and salt-related problems by investigating the effects of the depth of a corn (Zea mays L.) stover layer on soil water, salt distribution, and sunflower (Helianthus annuus L.) yield in the Hetao Irrigation District, Inner Mongolia, China via four treatments: deep tillage without stover (control) and a stover layer (9 Mg ha−1) at depths of 20 (M20), 40 (M40), and 60 cm (M60). Soil water storage was greater with increasing stover depth at planting, and at seedling and budding at 0 to 40 cm deep. The soil water storage of M60 at planting exceeded that of the control by 10% (2013) and 11% (2014). However, M20 and M40 retained less soil water than the control by 7 and 6% at the seedling stage, respectively. (continued)


      doi:10.2135/cropsci2015.05.0305
      Published: May 27, 2016



    • Andrea Cavalieri, K. Neil Harker, Linda M. Hall, Christian J. Willenborg, Teketel A. Haile, Steven J. Shirtliffe and Robert H. Gulden
      Evaluation of the Causes of On-Farm Harvest Losses in Canola in the Northern Great Plains

      Canola (Brassica napus L.) is the main oilseed crop grown in the northern Great Plains (Canada). This species, however, also is associated with significant seed losses before and during harvest. To determine the factors that contribute to on-farm harvest losses in B. napus, an extensive on-farm survey was conducted in four regions across the northern Great Plains in 2010, 2011, and 2012. (continued)


      doi:10.2135/cropsci2016.01.0014
      Published: May 20, 2016



    • Amanda M. Goffnett, Christy L. Sprague, Fernando Mendoza and Karen A. Cichy
      Preharvest Herbicide Treatments Affect Black Bean Desiccation, Yield, and Canned Bean Color

      To facilitate direct harvest, preharvest herbicide applications are used to desiccate weeds and to accelerate and promote uniform dry bean (Phaseolus vulgaris L.) maturation. Field trials were conducted near Richville, MI, in 2013 and 2014 to evaluate the effects of preharvest herbicide treatments on desiccation, yield, and canned black bean quality and color. Three black bean cultivars, Zorro, Eclipse, and Zenith, were planted on two different dates in each of 2 yr. Three preharvest herbicide treatments, paraquat, glyphosate, and saflufenacil, were applied at a standard (pods = 80% yellow) and an early (pods = 50% yellow) application timing. (continued)


      doi:10.2135/cropsci2015.08.0469
      Published: May 6, 2016



    • Michelle J. Serapiglia, Akwasi A. Boateng, D.K. Lee and Michael D. Casler
      Switchgrass Harvest Time Management Can Impact Biomass Yield and Nutrient Content

      Switchgrass (Panicum virgatum L.) is a dedicated energy crop native to tallgrass prairie and savanna ecosystems of North America. Although high biomass yield is of significant importance for the development of switchgrass as a bioenergy crop, mineral nutrients in biomass are critically important for sustainable bioenergy crop production but are detrimental for thermochemical conversion of biomass to energy. To evaluate biomass yield and nutrient uptake or nutrient cycling in switchgrass cultivars, replicated trials across three sites (Arlington, WI; Marshfield, WI; and Urbana, IL) were established in 2009. The switchgrass cultivars were harvested once annually at upland peak, after killing frost, or post-winter in the spring from 2010 to 2014. (continued)


      doi:10.2135/cropsci2015.08.0527
      Published: April 29, 2016



    • Lena D. Syrovy, Steven J. Shirtliffe and Mark E. Zarnstorff
      Yield Response to Early Defoliation in Spring-Planted Canola

      Canola (Brassica napus L.) is a high-value summer annual crop grown in the northern Great Plains of Canada and the United States. During the early stages of its life, the crop may lose leaf area as a result of spring hail storms, frost, herbicides, animal grazing, and insects. However, little information is available on the effect of defoliation during vegetative growth on yield for spring-planted canola. To address this gap, a five site-year study was conducted in central Saskatchewan, Canada, to test canola recovery from partial (50%) or full (100%) defoliation at five stages before flowering (2-, 4-, 6-, 8-, and 10-leaf stages). (continued)


      doi:10.2135/cropsci2015.09.0556
      Published: April 15, 2016



  • CROP PHYSIOLOGY & METABOLIM

    • Luis Ignacio Mayer, Roxana Savin and Gustavo Angel Maddonni
      Heat Stress during Grain Filling Modifies Kernel Protein Composition in Field-Grown Maize

      Episodes of extremely high temperatures (>35°C) may cause a premature cessation of maize kernel growth (i.e., heat stress), depressing crop grain yield. However, little is known about the influence of this constraint on chemical composition of maize kernels, a key trait for end-use related attributes. Four maize genotypes (flint, popcorn, temperate semi-dent, and temperate × tropical semi-dent) with distinctive endosperm types were grown at heated and non-heated temperature regimes during the early or late stages of the effective grain-filling period. Heat stress during early stages decreased both protein and starch contents of kernels, but the impact on the former was lower (up to −42%) than on the latter (up to −50%), resulting in increases of kernel protein concentration (up to +14%). (continued)


      doi:10.2135/cropsci2015.09.0537
      Published: May 27, 2016



  • CROP PHYSIOLOGY & METABOLISM

    • L. Krishnamurthy, Hari D. Upadhyaya, J. Kashiwagi, R. Purushothaman, Sangam L. Dwivedi and V. Vadez
      Variation in Drought-Tolerance Components and their Interrelationships in the Minicore Collection of Finger Millet Germplasm

      Finger millet [Eleusine coracana (L.) Gaertn.] is an important and nutritious cereal cultivated largely in the tropics of Africa and Asia. It is adversely affected by intermittent droughts, and a trait-based selection for drought tolerance is expected to enhance yield stability. The current work has segregated the shoot biomass as total water use (T) and transpiration efficiency (TE) and assessed the importance of these components and their association with drought tolerance. A major part of the minicore collection of finger millet germplasm (n = 69) was evaluated in mini-lysimeters for the variation in T and TE under both terminal drought-stress (DS) and well-watered (WW) environments. (continued)


      doi:10.2135/cropsci2016.03.0191
      Published: May 27, 2016



    • Sukhbir Singh, Sangamesh V. Angadi, Rolston St. Hilaire, Kulbhushan Grover and Dawn M. VanLeeuwen
      Spring Safflower Performance under Growth Stage Based Irrigation in the Southern High Plains

      Water stress is the most important environmental factor limiting crop yield in the southern High Plains. Drought tolerant crops along with deficit irrigation strategies may be promising for sustainable agriculture in the region. The objective of this study was to assess water relations, photosynthesis, yield-forming components, and yield of spring safflower (Carthamus tinctorius L.) cultivars under growth stage based irrigation management. A blocked split plot design was used with irrigation treatments (fully irrigated [FI], stress at vegetative stage [VS], stress at reproductive stage [RS], and dryland [DL]) as the main plot and cultivars (PI8311, 99OL and Nutrisaff) as subplot in four replications. (continued)


      doi:10.2135/cropsci2015.08.0481
      Published: May 20, 2016



    • Mitchell L. Wise, Marcus A. Vinje and Shawn P. Conley
      Field Application of Benzothiadiazole (BTH) to Oats ( Avena sativa ): Effects on Crown Rust Resistance and Avenanthramide Production

      Avenanthramides are phenolic antioxidants produced in oat (Avena sativa L.) in response to fungal infection and, as shown in greenhouse experiments, by treatment with plant defense activators, such as benzothiadiazole (BTH). Presented here are the results of application of BTH under field conditions. Field trials were conducted in 2013 using four application rates, approximating manufacturer’s recommendations, on two oat cultivars and in 2014 using three application rates on three oat cultivars. The results showed a subtle but demonstrable effect of increased avenanthramide production in vegetative tissue and mature grain and enhanced resistance to crown rust infection. (continued)


      doi:10.2135/cropsci2015.11.0712
      Published: May 13, 2016



    • Bandara Gajanayake and K. Raja Reddy
      Sweetpotato Responses to Mid- and Late-Season Soil Moisture Deficits

      Soil moisture-dependent, quantitative information on sweetpotato [Ipomoea batatas L. (Lam)] plant processes is vital for crop management and modeling because of the projected shrinking and uneven distributions of rainfall and irrigation water supply due to climate change. This study was conducted to quantify the growth, physiology, biomass, and storage root yield responses of sweetpotato under four evapotranspiration-based irrigation treatments (100, 60, 40, and 20% ET) in sunlit growth chambers. Irrigation treatments were imposed from 41 to 97 d after transplanting. (continued)


      doi:10.2135/cropsci2015.03.0154
      Published: April 29, 2016



  • FORAGE & GRAZINGLANDS

    • Patrick D. Keyser, Amanda J. Ashworth, Fred L. Allen and Gary E. Bates
      Evaluation of Small Grain Cover Crops to Enhance Switchgrass Establishment

      Establishment failures are a challenge to wide-scale use of switchgrass (Panicum virgatum L.) for biomass feedstock and/or forage production. Small grain cover crops, because of their allelopathic properties, may inhibit (direct allelopathy) or enhance (competition reduction) switchgrass establishment, and provide indirect benefits such as soil conservation and forage/grain production during the establishment year. Objectives of this study were to evaluate stand density and yield based on seeding switchgrass into (i) four small grain cover crops: wheat (Triticum aestivum L.), cereal rye (Secale cereale L.), barley (Hordeum vulgare L.), oat (Avena sativa L.), and fallow control at (ii) three dates (15 March, 1 May, and 10 June) that approximated typical timing for removal of small grain cover, haylage, or grain crops in Tennessee, respectively. Treatments were assigned in a split-plot design with three replications at three locations in Tennessee in 2008 and repeated in 2009. (continued)


      doi:10.2135/cropsci2015.12.0783
      Published: May 27, 2016



    • Benjamin F. Tracy, Ken Albrecht, Joao Flores, Marvin Hall, Anowarul Islam, Gordon Jones, William Lamp, Jennifer W. MacAdam, Howard Skinner and Chris Teutsch
      Evaluation of Alfalfa–Tall Fescue Mixtures across Multiple Environments

      Binary grass–legume mixtures can benefit forage production systems in different ways helping growers cope both with increasing input costs (e.g., N fertilizer, herbicides) and potentially more variable weather. The main objective of this study was to evaluate alfalfa (Medicago sativa L.) and tall fescue [Schedonorus phoenix (Scop.) Holub] mixtures across a wide range of environments to assess herbage accumulation, weed suppression and fertilizer nitrogen replacement values (FNRV). A common field experiment was established in 2009 and 2010 at six study sites in the United States: Maryland, Pennsylvania, Utah, Virginia, Wisconsin, and Wyoming. Experimental treatments included an alfalfa monoculture, three alfalfa–fescue mixtures with seed ratios of 75:25, 50:50, and 25:75 of alfalfa/tall fescue, and tall fescue monocultures that received nitrogen applications of 0, 50, 100, 150, 200, and 300 kg N ha–1, respectively. (continued)


      doi:10.2135/cropsci2015.09.0553
      Published: May 20, 2016



    • R. Howard Skinner and Curtis J. Dell
      Yield and Soil Carbon Sequestration in Grazed Pastures Sown with Two or Five Forage Species

      Increasing plant species richness is often associated with an increase in productivity and associated ecosystem services such as soil C sequestration. Here we report on a 9-yr experiment to evaluate the forage production and C sequestration potential of grazed pastures sown to either a two-species cool-season grass-legume mixture or a five-species mixture of grasses, legumes, and a non-legume forb. We hypothesized that forage production and soil C sequestration would be greater in the five-species compared with the two-species mixture. We also evaluated the effects of rainfall and temperature on the difference in forage production between mixtures. (continued)


      doi:10.2135/cropsci2015.11.0711
      Published: April 29, 2016



    • Valdson J. Silva, Carlos G.S. Pedreira, Lynn E. Sollenberger, Liliane S. Silva, Júnior I. Yasuoka and Ianê C.L. Almeida
      Canopy Height and Nitrogen Affect Herbage Accumulation, Nutritive Value, and Grazing Efficiency of ‘Mulato II’ Brachiariagrass

      Brachiaria sp. grasses are widely used in planted pastures in Brazil. ‘Mulato II’ is a productive Brachiaria hybrid (B. ruziziensis × B. (continued)


      doi:10.2135/cropsci2015.12.0764
      Published: April 29, 2016



    • R. Howard Skinner and Sarah C. Goslee
      Defoliation Effects on Pasture Photosynthesis and Respiration

      Ecosystem C gain or loss from managed grasslands depends on management practices. However, limited information is available at the field scale on how the type of defoliation, specifically grazing vs. cutting, affects gross primary productivity (GPP) and ecosystem respiration (RE) immediately after defoliation and during the regrowth process. This study takes advantage of daily field-scale micrometeorological measurements of GPP and RE made over a 9-yr period on two pastures that were grazed or cut approximately five times per year to examine the relative effects of grazing and cutting on GPP and RE. (continued)


      doi:10.2135/cropsci2015.12.0733
      Published: April 15, 2016



  • G X E SPECIAL SECTION

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

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


      doi:10.2135/cropsci2015.04.0231
      Published: February 12, 2016



  • GENOMICS, MOLECULAR GENETICS & BIOTECHNOLOGY

    • Erika Roach, Sjoerd W. Duiker and Surinder Chopra
      Soil Management Affects Expression of Genes Involved in Carbon and Nitrogen Metabolism in Maize

      Agronomic practices affect plant growth, development, and productivity through modifications of plant physiological processes. The effect of cover crop (hairy vetch [Vicia villosa Roth subsp. villosa]), no-tillage, and N fertilizer side-dressing on plant and soil health and expression of maize (Zea mays L.) genes was measured throughout the growing season. Expression of ACS, GS2, ICDH, NiR, and PEPC genes involved in C and N metabolism was determined. (continued)


      doi:10.2135/cropsci2015.08.0488
      Published: May 27, 2016



    • Gyu Tae Park, Jagadeesh Sundaramoorthy, Jeong-Dong Lee, Jeong Hoe Kim, Soon-Ki Park, Hak Soo Seo and Jong Tae Song
      Association of New Mutant Allele, w4 - nw, at W4 Locus with Near-White Flower Color in Soybean

      An ethyl methanesulfonate-induced mutant (PE1033) with near-white flowers was isolated from the soybean [Glycine max (L.) Merr.] cultivar Pungsannamul with purple flowers that had the W1w3W4 genotype. In the present study, we aimed to investigate the genetic and molecular bases of the flower color variation displayed by the PE1033 mutant. Analyses of genomic sequences and reverse transcription–polymerase chain reaction (RT-PCR) revealed that the color variation of PE1033 flowers originated from a recessive mutation in the W4 locus that encodes dihydroflavonol 4-reductase (DFR) 2. The new mutant allele, named w4-nw, harbored a single-nucleotide substitution (G to A) at the 5′ spliceosome recognition site in the first intron of DFR2, resulting in the failure of splicing and producing two different abnormal transcripts: w4-nw-a and w4-nw-b. (continued)


      doi:10.2135/cropsci2016.01.0026
      Published: May 20, 2016



    • Jessica L. Shoup Rupp, Luisa F. Cruz, Harold N. Trick and John P. Fellers
      RNAi-Mediated, Stable Resistance to Triticum mosaic virus in Wheat

      Triticum mosaic virus (TriMV) was discovered in 2006 and affects wheat (Triticum spp.) production systems in the Great Plains of the United States. Genetic resistance is available in a few commercial varieties; however, it is not effective above 20°C. RNA interference (RNAi) was evaluated as an alternative strategy to generate resistance to TriMV. An RNAi pANDA-mini-based hairpin expression vector was created from 272 bp of the TriMV coat protein (CP) sequence. (continued)


      doi:10.2135/cropsci2015.09.0577
      Published: April 22, 2016



    • Xiaojie Zhao, Xuke Lu, Zujun Yin, Delong Wang, Junjuan Wang, Weili Fan, Shuai Wang, Tianbao Zhang and Wuwei Ye
      Genome-wide Identification and Structural Analysis of Pyrophosphatase Gene Family in Cotton

      Pyrophosphatase is a hydrolytic enzyme that utilizes pyrophosphate as a substrate. H+-PPase, an important proton pump on the vacuolar membrane, plays an important role in regulating cell expansion, H+ electrochemical gradient, and secondary active transport of inorganic ions, organic acids and saccharides. Under low temperature, drought, high NaCl concentration, and hypoxia, H+-PPase gene expression is promoted to maintain the intracellular balance and enhance the ability of stress resistance in plants. The GhVP gene family is a class of H+-PPase genes in Gossypium hirsutum L. (continued)


      doi:10.2135/cropsci2014.12.0832
      Published: April 15, 2016



    • Scott L. McClinchey, J. Brent Gillespie, Tracey L. Fisher, Kerry Taylor, Mary Challender and Daria H. Schmidt
      Quality Characteristics of Glyphosate-Tolerant Canola Cultivars Containing a Glyphosate Acetyltransferase Transgene (Event DP-Ø73496-4)

      Canola (Brassica napus L.) was transformed with an insert that expresses the GAT4621 protein, conferring tolerance to the nonselective herbicidal ingredient glyphosate. Event DP-Ø73496-4 (trade name Optimum GLY Canola) was introgressed into additional female inbred genetic backgrounds and hybrid seed lots were created to evaluate canola quality characteristics for cultivar registration in Canada. Field trials were conducted in 2012 and 2013 across several locations in appropriate maturity zones for the cultivars. Results indicated no difference for key canola quality parameters across genetic backgrounds and locations. (continued)


      doi:10.2135/cropsci2015.12.0744
      Published: April 15, 2016



  • OPINION & POLICY

    • Shelley H. Jansky, Amy O. Charkowski, David S. Douches, Gabe Gusmini, Craig Richael, Paul C. Bethke, David M. Spooner, Richard G. Novy, Hielke De Jong, Walter S. De Jong, John B. Bamberg, A. L. Thompson, Benoit Bizimungu, David G. Holm, Chuck R. Brown, Kathleen G. Haynes, Vidyasagar R. Sathuvalli, Richard E. Veilleux, J. Creighton Miller, Jim M. Bradeen and Jiming M. Jiang
      Reinventing Potato as a Diploid Inbred Line–Based Crop

      The third most important food crop worldwide, potato (Solanum tuberosum L.) is a tetraploid outcrossing species propagated from tubers. Breeders have long been challenged by polyploidy, heterozygosity, and asexual reproduction. It has been assumed that tetraploidy is essential for high yield, that the creation of inbred potato is not feasible, and that propagation by seed tubers is ideal. In this paper, we question those assumptions and propose to convert potato into a diploid inbred line–based crop propagated by true seed. (continued)


      doi:10.2135/cropsci2015.12.0740
      Published: April 15, 2016



  • PLANT GENETIC RESOURCES

    • Genqiao Li, Xiangyang Xu, Guihua Bai, Brett F. Carver, Robert Hunger and J. Michael Bonman
      Identification of Novel Powdery Mildew Resistance Sources in Wheat

      Genetic resistance plays an important role in managing powdery mildew of wheat (Triticum aestivum L.), a disease of global importance. The objectives of this study were to evaluate powdery mildew resistance and the underlying genes in US wheat breeding lines and identify novel resistance sources from a worldwide collection of winter wheat germplasm. Our results suggested that 37.5% of powdery mildew resistant breeding lines recently developed in the United States carry the Pm3a gene, indicating the abundance of Pm3a in US cultivars. Among a worldwide collection of 1,297 landraces and 874 early cultivars or breeding lines, 59 and 68 accessions showed high (HR) and moderate resistance (MR), respectively. (continued)


      doi:10.2135/cropsci2015.09.0551
      Published: May 27, 2016



    • Adam L. Bray, Lauren A. Lail, John N. All, Zenglu Li and Wayne A. Parrott
      Phenotyping Techniques and Identification of Soybean Resistance to the Kudzu Bug

      The kudzu bug (KZB), Megacopta punctatissima Montandon 1896, is a newly invasive Asian pest of soybean [Glycine max (L.) Merrill] in the southeastern United States. Due to the unique biology of this soybean pest, six screening techniques were tested to identify host plant resistance (HPR) to KZB. Soybean lines previously characterized as resistant to either leaf-chewing or piercing–sucking insects were used to test screening techniques and to identify potential sources of KZB resistance. Four open field experiments and one field cage experiment were conducted in 2010 to 2013 to screen ‘Benning’ near-isogenic lines (NILs) for KZB resistance. (continued)


      doi:10.2135/cropsci2015.09.0536
      Published: May 27, 2016



    • Marcos Doniseti Michelotto, Ignácio José de Godoy, João Francisco dos Santos, Antonio Lucio Mello Martins, Eduardo Leonardecz and Alessandra Pereira Fávero
      Identifying Arachis Amphidiploids Resistant to Foliar Fungal Diseases

      Many wild species of the genus Arachis are more resistant to pests and diseases than the cultivated species A. hypogaea. However, the use of Arachis germplasm in breeding programs is hampered by sterility barriers mainly due to differences between the genomes and the ploidy levels of A. hypogaea and related species. (continued)


      doi:10.2135/cropsci2015.06.0393
      Published: May 27, 2016



    • Mizan Tesfay Abraha, Hussein Shimelis, Mark Laing and Kebebew Assefa
      Performance of Tef [ Eragrostis tef (Zucc.) Trotter] Genotypes for Yield and Yield Components Under Drought-Stressed and Non-Stressed Conditions

      Tef [Eragrostis tef (Zucc.) Trotter] is a staple food crop in Ethiopia, and has become known globally as a health food for its gluten-free flour, which also has a unique nutritional profile. A key to successful variety development through designed breeding is the use of diverse genetic resources, especially when breeding for complex traits such as tolerance to drought stress. The objective of this study was to assess the response of genetically diverse populations of tef genotypes for yield and yield components, with special emphasis on drought-stress tolerance, to select promising parents for breeding. One hundred forty-four tef genotypes were evaluated, involving four experiments representing optimum moisture and drought-stressed environments. (continued)


      doi:10.2135/cropsci2015.07.0449
      Published: April 15, 2016



  • REVIEW & INTERPRETATION

    • Stephen Smith, Sergio Lence, Dermot Hayes, Julian Alston and Eloy Corona
      Elements of Intellectual Property Protection in Plant Breeding and Biotechnology: Interactions and Outcomes

      Public and private investments in plant breeding have a proven track record of increasing agricultural productivity, significantly contributing to economic well-being or social welfare. Substantial investments in research and development are required before a new plant variety can be developed and released, which the private sector can only recoup through commercial sales coupled with property rights. We previously published outcomes from economic modeling implementing different categories and hypothetical variants of intellectual property protection (IPP) in the field of plant breeding and biotechnology. Our goal here is to portray these outcomes using examples that will be more immediately familiar to the plant-breeding and policy-making communities. (continued)


      doi:10.2135/cropsci2015.10.0608
      Published: April 15, 2016



  • SEED PHYSIOLOGY, PRODUCTION & TECHNOLOGY

    • Sayareh Irani, Allen D. Knapp, Thomas Lubberstedt, Ursula Frei and Ehsan Askari
      Increasing Seed Viability of Maize Haploid Inducing Lines by Genetic and Non-Genetic Approaches

      Some haploid inducing lines used in the production of maize doubled haploids (DHs) express germination problems and reduced vigor. In this study, two reciprocal F1 populations of the haploid inducing lines RWS and RWK-76 were examined for viability by Tetrazolium (TZ) and germination ability by standard germination tests. Evaluation based on TZ tests showed that 59% of the seed of RWK-76/RWS were not viable, compared with only 12% dead seed in RWS/RWK-76. Similarly, the total germination and speed of germination in RWK-76/RWS (25%, 1.53) was lower than for RWS/RWK-76 (74%, 4.30). (continued)


      doi:10.2135/cropsci2015.11.0713
      Published: May 6, 2016



    • Loren Trimble, Stacie Shuler and William F. Tracy
      Characterization of Five Naturally Occurring Alleles at the Sugary1 Locus for Seed Composition, Seedling Emergence, and Isoamylase1 Activity

      The mutant su1-ref allele is of interest in the commercial sweet maize (Zea mays L.) industry. It was the only starch synthesis mutation used for sweet maize until the 1960s and is still used today, especially in combinations with other loci. The wild-type Su1 allele produces a starch debranching-type isoamylase, ISA1, required for normal amylopectin and starch granule crystal formation in maize endosperm. Five naturally occurring mutant alleles have been identified at the su1 locus, but they have not been characterized for seedling emergence, field traits, mature kernel composition, or ISA1 enzyme activity. (continued)


      doi:10.2135/cropsci2015.02.0117
      Published: April 15, 2016



  • SYMPOSIA

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

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


      doi:10.2135/cropsci2015.06.0357
      Published: May 27, 2016



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

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


      doi:10.2135/cropsci2015.07.0451
      Published: May 6, 2016



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

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


      doi:10.2135/cropsci2015.07.0405
      Published: March 11, 2016



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

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


      doi:10.2135/cropsci2015.08.0512
      Published: February 12, 2016



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

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


      doi:10.2135/cropsci2015.05.0311
      Published: February 5, 2016



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

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


      doi:10.2135/cropsci2015.04.0207
      Published: January 29, 2016



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

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


      doi:10.2135/cropsci2015.03.0152
      Published: September 25, 2015



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

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


      doi:10.2135/cropsci2015.06.0336
      Published: December 3, 2015



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

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


      doi:10.2135/cropsci2015.04.0260
      Published: December 3, 2015



  • TURFGRASS SCIENCE

    • William Casey Reynolds, Grady L. Miller, David P. Livingston and Thomas W. Rufty
      Athletic Field Paint Color Impacts Transpiration and Canopy Temperature in Bermudagrass

      Athletic field paints have varying impacts on turfgrass health that have been linked to their ability to alter photosynthetically active radiation and photosynthesis on the basis of color. It was further hypothesized they may also alter transpiration and canopy temperature by disrupting gas exchange at the leaf surface. Growth chamber experiments evaluated the effects of air temperature and six colors of paint on daily water loss and canopy temperature in ‘Tifway’ bermudagrass [Cynodon dactylon (L.) Pers. x C. (continued)


      doi:10.2135/cropsci2016.01.0028
      Published: May 20, 2016



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