bluuebunny/crossref_metadata_2025_split huggingface dataset:
Consensus Mapping and Identification of Markers for Marker‐Assisted Selection of Wsm2 in Wheat
Authors: Lu Huangjun , Kottke Rebecca , Devkota Ravindra , Amand Paul St. , Bernardo Amy , Bai Guihua , Byrne Patrick , Martin Terry Joe , Haley Scott D. , Rudd Jackie 
Published: April 2012

ABSTRACTA recently identified Wheat streak mosaic virus (WSMV) resistance gene Wsm2 confers a high level of resistance. Objective of this study was to identify closely linked DNA markers for Wsm2 for use in marker‐assisted selection (MAS) in wheat (Triticum aestivum L.). Two segregating populations (CO960293‐2 × ‘TAM 111’ and CO960293‐2 × ‘Yuma’) of F2:3 families were evaluated for response to WSMV infection in growth chamber experiments. Forty‐eight simple sequence repeat (SSR) or sequence‐tagged site (STS) markers were screened for polymorphism between the parents of both populations. In the CO960293‐2 × TAM 111 population, five markers were mapped to the region of Wsm2 with XSTS3B‐55 being the closest marker (5.2 cM distal to Wsm2). In the CO960293‐2 × Yuma population, eight markers were linked to Wsm2 with the closest marker Xbarc102 linked at 3.9 cM proximal to Wsm2. Results from consensus mapping of the two populations suggested that Xbarc102 was distal to Wsm2. The marker Xbarc102 was associated with Wsm2 in all 22 wheat lines derived from crosses between susceptible parents and either CO960293‐2 or ‘RonL’ (also carrying Wsm2). The marker allele Xbarc102‐219‐bp present in CO960293‐2 was amplified in polymerase chain reaction (PCR) from Wsm2‐carrying genotypes CO960293‐w133, RonL, and ‘Snowmass’ but not from the resistant line KS96HW10‐3 (carrying Wsm1) or the susceptible genotypes ‘Karl 92’, ‘TAM 107’, and ‘N96L9970’. Therefore, this marker should be useful for MAS of Wsm2 in breeding programs.
Frequent Trinexapac‐ethyl Applications Reduce Nitrogen Requirements of Creeping Bentgrass Golf Putting Greens
Authors: Kreuser William C. , Soldat Douglas J. 
Published: April 2012

ABSTRACTThe plant growth regulator trinexapac‐ethyl (TE) [4‐(cyclopropyl‐a‐hydroxymethylene)‐3,5‐dioxo‐cyclohexanecarboxylic acid ethylester] reduces turfgrass clipping yield and enhances turfgrass color and density. Typically, such responses are achieved through alteration of N application rate, yet few have comprehensively investigated the effect of TE on turfgrass N requirements. We hypothesized that TE reduces putting green N requirements without sacrificing turfgrass quality. A three year study was conducted on a creeping bentgrass (Agrostis stolonifera L.) putting green with treatments consisting of three N application rates (5, 10, and 20 kg N ha−1 14 d−1) with or without TE application. To sustain season‐long growth suppression, TE was applied at 0.10 kg a.i. ha−1 every 200 growing degree days (GDD; base 0°C). Turfgrass yield and color were quantified every other week, and clipping tissue N content was analyzed monthly. Clipping yield, tissue N content, N removal, and color index increased with N rate. All attributes responded linearly to N application rate. Trinexapac‐ethyl enhanced color while suppressing clipping yield and nutrient removal from mowing. As a result, TE reduced creeping bentgrass putting green N requirements by 25% conservatively and on several occasions by greater than 50%.
Timing and Frequency Effects of Lightweight Rolling on Dollar Spot Disease in Creeping Bentgrass Putting Greens
Authors: Giordano Paul R. , Nikolai Thomas A. , Hammerschmidt Ray , Vargas Joseph M. 
Published: April 2012

ABSTRACTDollar spot (DS) (Sclerotinia homoeocarpa F.T. Bennett) is an important disease on golf course turfgrasses in the United States. The objective of this study was to elucidate disease reduction mechanisms related to lightweight rolling. Creeping bentgrass (Agrostis stolonifera L.) plots that were subjected to daily (5 d wk−1) rolling treatments (1x a.m., 1x p.m., 2x a.m.) showed significant DS reductions when compared with a nonrolled control. Treatments rolled in the afternoon (after dew and guttation fluid dissipated) exhibited similar area under disease progress curve (AUDPC) values as treatments rolled in the morning in 2008, 2009, and 2010. Both 1x rolling treatments resulted in significant DS reductions compared with the control in 2009 and 2010. The 2x d−1 treatment exhibited significantly less DS than the control in all years as well as significantly lower AUDPC values than both 1x rolling treatments in 2009 and 2010. Rolling 2x d−1 improved turfgrass quality compared with all other treatments in each year of the study. All rolling treatments exhibited higher root zone volumetric water content (%VWC) compared with the control in 2010, and significant effects on %VWC were observed on individual dates among treatments. Results indicate previously unidentified effects of rolling on putting greens, including added physical and biological effects, which may be contributing to DS suppression.
Steer Consumption and Ergovaline Recovery from In Vitro Digested Residues of Tall Fescue Seedheads
Authors: Goff Ben M. , Aiken Glen E. , Witt William W. , Sleugh Byron B. , Burch Patrick L. 
Published: April 2012

ABSTRACTErgot alkaloids produced by the endophyte [Neotyphodium coenophialum (Morgan‐Jones and Gams) Glenn, Bacon, and Hanlin] of tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] are a common problem faced by livestock producers. These toxins are concentrated within seedheads of tall fescue, which cattle were observed to selectively graze. There appears to be little research showing the extent to which alkaloids are released from developing seedheads during digestion. Therefore, the objectives of this study were to determine the amount at which tall fescue seedheads were removed by cattle and to estimate the amount of ergovaline that is released from these tissues. Seedheads from tall fescue pastures were monitored for consumption by steers during summer 2010. Samples were digested with a two‐stage procedure, and ergovaline concentrations were determined using high‐performance liquid chromatography. By mean stage count 3.91 (Day of Year 155), 60.7 ± 2.87% of seedheads within the pastures had been grazed, and 2 wk later increased to nearly 78.8 ± 0.82%. Ergovaline concentrations of seedheads increased throughout the season and were highest in mid‐June. The percentage of ergovaline released from seedheads collected in mid‐June was lower than earlier dates, but the difference was small. Results of this study indicate that high concentrations of ergovaline are released from tall fescue seedheads during the growing season, and management strategies should be aimed at controlling reproductive growth of the grass.
Dissecting Genotype × Environment Interactions and Trait Correlations Present in the Pee Dee Cotton Germplasm Collection following Seventy Years of Plant Breeding
Authors: Campbell B. T. , Chee P. W. , Lubbers E. , Bowman D. T. , Meredith W. R. , Johnson J. , Fraser D. , Bridges W. , Jones D. C. 
Published: April 2012

ABSTRACTGenotype × environment (G × E) interactions and trait correlations significantly impact efforts to develop high‐yield, high‐quality, and environmentally stable Upland cotton (Gossypium hirsutum L.) cultivars. Knowledge of both can and should be used to design optimal breeding programs and effective selection criteria. In this study, we examined the G × E interactions and trait correlations present in the 70‐yr Pee Dee cotton germplasm enhancement program. Since beginning in 1935, the Pee Dee program has employed a variety of unique germplasm and breeding methods to release >80 improved germplasm lines and cultivars. Results suggest that significant G × E interactions exist for several agronomic and fiber quality performance traits that are mostly due to changes in magnitude. Negative genotypic correlations still persist between lint percent/lint yield and fiber length/fiber strength. However, apparently the breeding methods and selection criteria used over 70 yr have lessened the negative relationship between agronomic performance and fiber quality over time to some degree. The results provide cotton breeders a resource to select specific Pee Dee germplasm lines for increased environmental stability. Cotton breeders can also use the information herein to select specific Pee Dee germplasm lines that represent rare recombination events that combine high yield and fiber quality potential.
Interactions of Selected Potato Cultivars and Populations of Meloidogyne hapla Adapted to the Midwest U.S. Soils
Authors: Melakeberhan Haddish , Douches David , Wang Wei 
Published: April 2012

ABSTRACTMeloidogyne hapla Chitwood is among the most serious nematode pests in temperate vegetable crops grown in rotation with potato (Solanum tuberosum L.), a crop with known resistance to potato cyst. While the types of agronomic trait improvements, crops, and pests are limited by resources, preserving improved crops in a rotation system requires understanding their performance against nontarget pests such as M. hapla. In greenhouse experiments, the interactions of four populations of M. hapla (Mh 1, Mh 2, Mh 3, and Mh 4) and six potato cultivars and lines, including ‘Boulder’ and ‘Missaukee’ with the H1 gene, were tested. The potato cultivars showed a 12 to 33% degree of suitability to the populations of M. hapla when compared with tomato (Solanum lycopersicum L. [syn. Lycopersicon esculentum Mill.), the host in which the populations were cultured, indicating that buildup of the populations of M. hapla potentially may be a problem. However, the responses varied by M. hapla population and potato cultivar interactions, suggesting that the management challenges will be site specific. Of the four M. hapla populations, Mh 3, an isolate from sandy soil under extended methyl bromide and other pesticide application, was the most pathogenic. The study provides critical data for developing agro‐biologically integrated approaches to managing nematode parasitic variability.
Sensitivity of Gas Exchange Parameters to Ozone in Diverse C4 Sugarcane Hybrids
Authors: Grantz D. A. , Vu H.‐B. , Tew T. L. , Veremis J. C. 
Published: April 2012

ABSTRACTIn early studies, C4 species exhibited greater tolerance to O3 than C3 species. But a C4 Saccharum spp. hybrid (sugarcane, cv. Elephant Cane) exhibited high sensitivity to O3. To investigate whether Saccharum is uniquely sensitive to O3 we exposed a morphologically diverse set of congeners to a range of O3. Here we test the null hypothesis that these diverse genotypes do not differ in baseline responses of carbon assimilation to intercellular CO2 or in the sensitivity of these responses to elevated O3 (4, 58, and 114 nmol mol−1, 12 h means). Elephant Cane was most sensitive but all exhibited declines in net carbon assimilation (An) and in capacities of phosphoenolpyruvate carboxylase (PEPCase) and rubisco. Phosphoenolpyruvate carboxylase was more sensitive than rubisco. The clones were distinguished by morphological traits and by estimated fraction of Saccharum spontaneum L. in their lineages. Baseline values of photosynthetic parameters were not consistently related to pedigree while morphology and sensitivity to O3 exhibited strong relationships. These results are not consistent with a generalized resistance of C4 plants to O3. This single C4 genus exhibited a wide range of sensitivities. The results suggest that sufficient variation may exist among Saccharum genotypes to allow selection for resistance to O3 and that introgression of S. spontaneum germplasm may confer resistance to O3 along with resistance to other abiotic stresses. Reduced sensitivity to O3 in dedicated biofuel feedstocks may facilitate development of production systems in novel production areas.
Soybean Nitrogen Fixation and Nitrogen Remobilization during Reproductive Development
Authors: Mastrodomenico Adriano T. , Purcell Larry C. 
Published: April 2012

ABSTRACTSeed N is important for soybean [Glycine max (L.) Merr.] because of the high grain protein concentration. However, the association between N2 fixation and N remobilized from vegetative tissues to seed across different maturity groups (MGs) is not well understood. We hypothesized that increased amounts of biomass at the beginning of seedfill for late‐maturing genotypes would provide a larger pool of N that was available for remobilization during seedfill and would increase yield relative to earlier‐maturing genotypes. Near isolines for maturity (MG IV, V, and VI), a modern breeding line (R01‐416F, MG V), and a non‐nodulated soybean genotype (MG VI) were harvested periodically from beginning seedfill to physiological maturity to determine N remobilization and N2 fixation. Nitrogen fixation contributed approximately 90% of the seed N. The MG VI isoline accumulated larger N amounts in vegetative tissues than the MG IV isoline. Maturity isolines had similar seed N content, but the MG IV genotype had higher N harvest index (2009) than the MG VI isoline. In 2009, R01‐416F had greater yields and N content than the isolines, but there was no indication that N remobilization during seedfill was greater. These data indicate that N2 fixation continued until late seedfill and supplied nearly all of seed N. A large reservoir of N in the vegetative tissue of late MGs was not fully used, and N was not a limitation to yield under these conditions.
Quantitative Trait Loci for Fusarium Head Blight Resistance in U.S. Hard Winter Wheat Cultivar Heyne
Authors: Zhang Xianghui , Bai Guihua , Bockus Willium , Ji Xiaojia , Pan Hongyu 
Published: April 2012

ABSTRACTFusarium head blight (FHB), mainly caused by Fusarium graminearum Schwabe, is a destructive disease that can significantly reduce grain yield and quality. Quantitative trait loci (QTL) for FHB type II resistance have been identified in many Chinese cultivars and other sources but have not been reported in U.S. hard winter wheat (HWW) (Triticum aestivum L.) to date. ‘Heyne’ is a Kansas HWW with moderate type II resistance to FHB. In this study, recombinant inbred lines (RILs) derived from ‘Trego’ × Heyne were evaluated for FHB resistance by single‐floret inoculation in two field and three greenhouse experiments from 2009 to 2011. Percentage of symptomatic spikelets (PSS) in an inoculated spike was scored 18 d (in the greenhouse) and 21 d (in the field) postinoculation. A total of 209 polymorphic simple sequence repeats (SSRs) were used to screen the RILs. Three major QTL on chromosomes 3AS, 4DL, and 4AL were associated with FHB resistance. The QTL on 3AS was flanked by Xgwm5 and Xwmc428 and explained up to 17.9% of phenotypic variation. Another QTL on 4DL near Xwmc720 explained 13.8 to 23.4% of phenotypic variation. The third QTL on 4AL was flanked by Xwmc219 and Xgwm160 and explained up to 18.1% of the phenotypic variation. Heyne contributed all resistance alleles of three QTL, and these QTL were designated as Qfhb.hwwg‐3AS, Qfhb.hwwg‐4DL, and Qfhb.hwwg‐4AL. These QTL can be used for improving FHB resistance in U.S. HWW by pyramiding them with Fhb1 or other major resistance QTL from Asian sources.
Inheritance of the Low‐Phytate Trait in Pea
Authors: Rehman A. U. , Shunmugam A. , Arganosa G. , Bett K. E. , Warkentin T. D. 
Published: April 2012

ABSTRACTField pea (Pisum sativum L.) is the most widely grown pulse crop in Canada and has total seed P concentration greater than 3 mg g−1. However, about 60 to 80% of the total P is stored as phytate, an organic molecule that binds with some mineral cations and is excreted due to the lack of phytase enzymes in humans and non‐ruminant animals. This causes nutrient deficiency as well as environmental pollution. The objective of this research was to determine the genetic control of the low‐phytate trait in two recently developed pea lines: 1‐150‐81 and 1‐2347‐144. Both lines and two normal‐phytate cultivars were used in crosses to develop five populations, including one reciprocal. The F1 seeds from the five crosses all had normal phytate concentration, indicating recessive inheritance. The F2 segregation ratios for the five crosses fit a phenotypic ratio of 3 normal:1 low phytate. The F2 individuals from 12 backcross populations fit a ratio of 3:1 with the exception of one population (1‐150‐81/CDC Meadow//CDC Meadow). The segregation of 1057 F2:4 lines from the six single cross‐derived populations were tested and five of six populations fit a ratio of 1:2:1 homogeneous normal phytate:segregating:homogeneous low phytate. Taken together, these data support a single gene model with the low‐phytate phenotype being recessive. The two low‐phytate lines were intercrossed and the F2 seeds all displayed the low‐phytate phenotype indicating that the mutated genes were allelic.
Physiological Changes Associated with Wilt‐Induced Freezing Tolerance among Diverse Turf Performance Perennial Ryegrass Cultivars
Authors: Lanier J. D. , Ebdon J. S. , DaCosta M. 
Published: April 2012

ABSTRACTPerennial ryegrass (Lolium perenne L.) is a cool‐season turfgrass susceptible to low temperature injury. Wilt‐based irrigation (WI) is a common practice for scheduling irrigation to turf by allowing a mild, negative water imbalance to occur as an alternative to maintaining turf under nonlimiting soil moisture. Moisture stress has been shown to promote freezing tolerance but this has not been investigated in response to WI. Objectives of this study were to examine perennial ryegrass in response to WI (applied at 50% visual leaf roll) on freezing tolerance (median lethal temperature at 50% survival [LT50]), 13C discrimination (Δ), internal leaf‐to‐ambient CO2 concentration (ci:ca) ratio, leaf water, rooting, water use efficiency (WUE), and wilting tendency (days to wilt and number of wilt events) among three top‐performing (TP) and three bottom‐performing (BP) perennial ryegrass cultivars. Cultivars were selected based on turf quality trials from a northern location (Orono, ME). Plant measurements were made in the greenhouse in 2007 and 2008 comparing the first (single) and last (multiple) wilt cycle after 68 d of irrigation between well watered and WI. Multiple wilt exposures significantly enhanced freezing tolerance compared to a single wilt event for TP cultivars only, but gains in freezing tolerance were small (<1.0°C). Freezing tolerance (lower LT50 values) was generally associated with lower yield, WUE, and leaf water content. In some TP cultivars, wilt‐induced freezing tolerance was associated with greater wilting tendency and drought sensitivity indicated by lower Δ values and ci:ca ratio. Repeated wilt exposures increased rooting over a single wilt event.
Post‐Flowering Assimilate Availability Regulates Oil Fatty Acid Composition in Sunflower Grains
Authors: Echarte María M. , Alberdi Ignacio , Aguirrezábal Luis A.N. 
Published: April 2012

ABSTRACTFatty acid composition of Helianthus annuus L. (sunflower) oil depends on intercepted solar radiation per plant (ISR) during grain filling. This effect could be accounted for by the assimilate availability of the grains (the source‐sink ratio). However, the current physiological‐biochemical knowledge does not consider any effect of carbon availability on oil fatty acid composition. The objective of this work was to address the regulation of fatty acid composition by assimilate supply to sunflower grains. A wide range of source‐sink ratios was obtained by manipulating either the source or the sink during grain filling. Assimilate supply was also modified by injecting sucrose into the receptacle of sunflower capitula. Grain weight and oil content depended on both ISR and source‐sink ratio in a curvilinear manner. When sink size was decreased by grain excision, ISR failed to explain oil fatty acid composition, while source‐sink ratio appropriately described it. Sucrose injection significantly increased grain weight, oil content, and oleic acid percentage of shaded plants. It is concluded that effects of ISR on fatty acid composition are a consequence of changes in assimilate availability for grain oil synthesis. To explain these results a conceptual model is proposed: when assimilate supply limits grain growth and oil synthesis, mainly linoleic acid is synthesized. As the assimilate supply increases, oleic acid desaturation process gets saturated and oleic acid accumulates.
Efficiency of Managed‐Stress Screening of Elite Maize Hybrids under Drought and Low Nitrogen for Yield under Rainfed Conditions in Southern Africa
Authors: Weber Vanessa S. , Melchinger Albrecht E. , Magorokosho Cosmos , Makumbi Dan , Bänziger Marianne , Atlin Gary N. 
Published: April 2012

ABSTRACTMaize (Zea mays L.) yields in southern Africa are low, due largely to drought and low‐N stress. Selection of stress‐tolerant genotypes by CIMMYT is conducted indirectly under managed stress conditions, although the selection efficiency of this approach is not known. A retrospective analysis of 704 elite hybrid trials conducted from 2001 to 2009 was used to determine the relative ability of optimal, low‐N, and managed drought trials to predict performance under the conditions of random abiotic stress and low‐N fertility usually faced by African farmers. Well‐fertilized trials in the rainy season were categorized as having experienced random abiotic stress if mean yield was <3 t ha−1 and the yield–anthesis date correlation was <0.1; otherwise they were classed as optimal. High genetic correlations were estimated between random abiotic stress and low‐N or optimal conditions. Heritability was highest under optimal conditions and lowest under random abiotic stress. Indirect selection under low‐N and optimal conditions was more efficient than direct selection under random abiotic stress or indirect selection under managed drought, especially for early maturing genotypes, but direct selection was most efficient for predicting performance under low N. Elite maize hybrids tolerant to random abiotic stress can be most efficiently selected under optimal and/or low‐N conditions while low‐N tolerant genotypes should be selected directly under low N.
Maximizing Genetic, Morphological, and Geographic Diversity in a Core Collection of Australian Bermudagrass
Authors: Jewell Margaret C. , Zhou Yi. , Loch Don S. , Godwin Ian D. , Lambrides Christopher J. 
Published: April 2012

ABSTRACTBermudagrasses (Cynodonspp.) are genetically and morphologically diverse warm‐season species that are valuable for turf and forage. Diverse accessions ofCynodonare preserved in various germplasm banks in Asia, Europe, and the United States. However, the extent of genetic and ecological diversity within Australia has not been previously explored and characterized. To address this issue, a broad‐scale collection ofCynodongermplasm across Australia was recently conducted. A core collection was generated from this resource to optimize its utilization in breeding and research. Genetic diversity of 690Cynodonaccessions was characterized using 16 expressed sequence tag (EST)‐simple sequence repeat (SSR) markers. The mean number of alleles generated was 7.44 per marker. Genetic data was combined with passport, ploidy level, morphological, and experimental performance data to generate a core collection using a directed stratified sampling method. The core collection comprised 13% of the source germplasm and captured 96% of the allelic diversity. Redundancy within the core collection was avoided with all accessions representing unique genotypes. This core collection will facilitate the future use of Australian germplasm inCynodonbreeding, genomics, conservation, taxonomy, and phylogeographical research.