bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of Soybean Cyst Nematode Resistance in Transgenic Hairy Roots of Soybean
Authors: Narayanan R. A. , Atz R. , Denny R. , Young N. D. , Somers D. A. 
Published: July 2010

ABSTRACTTransgenic hairy roots of soybean [Glycine max (L.) Merrill] induced by Agrobacterium rhizogenes support the complete life cycle of soybean cyst nematode (SCN, Heterodera glycines Ichinohe) in vitro. However, expression of SCN resistance in hairy soybean roots has not been investigated. A transgenic hairy root system would be useful in developing an assay for candidate SCN resistance genes. The objectives of this study were to characterize transgene expression in SCN‐infected hairy soybean roots and to evaluate a transgenic hairy root system for investigations of resistance to SCN. Seedling cotyledons of the SCN‐susceptible cultivars, Agassiz and Parker, and SCN‐resistant Bell and Faribault were infected with A. rhizogenes strain K599 transformed with T‐DNA binary vectors containing the gusA gene fused to promoters from either the cauliflower mosaic virus (CaMV 35S), Arabidopsis thaliana phenylalanine ammonia lyase (PAL), or bean (Phaseolus vulgaris L.) chalcone synthase‐8 (CHS) genes. Nine days after inoculating transgenic hairy roots with sterile J2 nematodes, CHS‐regulated β‐glucuronidase (GUS) staining at infection sites increased in hairy roots of resistant Faribault and decreased in susceptible Agassiz. PAL‐regulated GUS staining was absent at infection sites in hairy roots of resistant cultivars, but was increased in infection sites in susceptible cultivars. Thirty‐five days after inoculation with SCN, the mean number of cysts formed on hairy roots of the resistant cultivars was about 14% of the mean number of cysts formed on hairy roots of the susceptible cultivars, indicating that the SCN resistance phenotypes were preserved in transgenic hairy roots. These results indicated that the transgenic hairy soybean root system will be useful for investigating differential transgene expression during nematode infection and evaluation of candidate SCN resistance genes.
Survival of Wheat Curl Mites on Different Sources of Resistance in Wheat
Authors: Harvey T. L. , Seifers D. L. , Martin T. J. , Brown‐Guedira G. , Gill B. S. 
Published: July 2010

ABSTRACTWheat (Triticum aestivum L.) yield is limited by wheat streak mosaic virus which is vectored by the wheat curl mite (WCM) Aceria tosicheilla (Keifer). Host resistance to WCM has reduced losses. This study was conducted to evaluate the effectiveness of resistance in wheat to WCM collected from various locations in the Great Plains. Collections of WCM from Montana, Nebraska, South Dakota, Texas, Alberta, Canada, and eight locations in Kansas were compared for their ability to survive and reproduce in the greenhouse on seven lines of wheat and wheat relatives previously identified as resistant. The lines and their sources of resistance were: AC PGR16635 (Aegilops tauschii Coss., Cmc1), PI 525452 (Thinopyrum ponticum (Podp.) Liu and Wang, Cmc2), KS96WGRC40 (Ae. tauschii and Secale cereale L.), TA920 (Triticum timopheevii (Zhuk.) Zhuk spp. armenidcum), PI 475772 (S. cereale), ‘TAM 107’ (S. cereale), PI 222655 (T. aestivum). KS96WGRC40 and TA920 were the only entries that were resistant to all WCM collections. Other sources of resistance were effective against WCMs from some but not all locations. PI 222655 was resistant to WCMs from Nebraska and central Kansas but not to mites from most other locations. WCMs that were virulent to TAM 107 generally were also virulent to PIs 222655 and 475772 but avirulent to Cmc2. The WCMs from western Kansas, where TAM 107 is widely grown, were generally more virulent to that cultivar than WCM from central Kansas where the hectarage of TAM 107 is smaller. WCMs collected at different times or locations may vary in their responses to different sources of resistance; therefore, testing mites for their response to resistance genes advanced in breeding programs may be needed before resistant cultivars are deployed in the field.
Inheritance of Medium Stearic Acid Content in the Seed Oil of a Sunflower Mutant CAS‐4
Authors: Pérez‐Vich Begoña , Garcés Rafael , Fernández‐Martínez Jose María 
Published: July 2010

ABSTRACTThe sunflower (Helianthus annuus L.) line CAS‐4 obtained by mutagenesis has an increased stearic acid (C18:0) content in its seed oil (130 g kg−1), which is desired for some food products. The objectives of this study were to determine (i) the inheritance of medium C18:0 content in CAS‐4, (ii) the relationship between CAS‐4 and the high C18:0 mutant CAS‐3, and (iii) if recombinants with higher C18:0 content than CAS‐3 could be obtained. CAS‐4 was reciprocally crossed with its original parental line RDF‐1‐532 (80 g kg−1 C18:0), HA‐89 (standard low 50 g kg−1 C18:0), and CAS‐3 (250 g kg−1 C18:0). The fatty acid content of the F1, F2, BC1F1 to both parents, and F3 seeds was analyzed by gas‐liquid chromatography (GLC). Alleles controlling low C18:0 exhibited partial dominance to those for medium C18:0, and these were partially dominant to those for high C18:0. Segregation patterns fit a two‐loci model for the HA‐89 × CAS‐4 cross and one‐locus model for the RDF‐1‐532 × CAS‐4 and the CAS‐3 × CAS‐4 crosses. We concluded that medium C18:0 content of CAS‐4 was controlled by alleles at the Es1 and Es2 loci previously identified in CAS‐3, or at tightly linked loci. The CAS‐4 alleles at the Es2 locus are those present in CAS‐3 (es2es2), whereas the alleles at the Es1 locus are different from those of CAS‐3 (es1es1) and have been designated es1bes1b The proposed genotype (C18:0 content) of CAS‐4 is es1bes1bes2es2 The continuous distribution observed in the HA‐89 crosses with CAS‐4 indicated that minor genes and environmental effects also are important in the expression of C18:0 content in CAS‐4.
Genetic Distance among Selected Cotton Genotypes and Its Relationship with F2 Performance
Authors: Gutiérrez O. A. , Basu S. , Saha S. , Jenkins J. N. , Shoemaker D. B. , Cheatham C. L. , McCarty J. C. 
Published: July 2010

ABSTRACTKnowledge of genetic diversity and relationships among breeding materials has a significant impact on crop improvement. Association between parental divergence and progeny performance has not been well documented in cotton (Gossypium hirsutum L.). The objectives of this study were to estimate genetic diversity among selected cotton genotypes on the basis of simple sequence repeat (SSR) markers, and to investigate the relationship between genetic diversity and F2‐bulk population performance. Five U.S. and four Australian cultivars, and two day‐neutral converted lines of G. hirsutum were genotyped by means of 90 SSR primer pairs providing 69 polymorphic marker loci. Genetic distance (GD) between genotypes ranged from 0.06 to 0.34 for the 11 parental genotypes. The highest GD (0.34) was observed between ST474 and the day‐neutral converted line B1388. The lowest GD (0.06) was detected between cultivars FM832 and FM975. The GD between day‐neutral converted lines and cultivars ranged from 0.26 to 0.34. Among the Australian cultivars, GD ranged from 0.06 to 0.19 while GD among U.S. cultivars varied from 0.10 to 0.22, indicating a narrow genetic base. Significant correlations between agronomic and fiber traits of F2‐bulk populations and GD ranged from negative to positive depending on the traits, genetic background, and environment. On the basis of SSR markers, GD revealed a lack of genetic diversity among all genotypes and it was a poor predictor of overall F2 performance. However, when genotypes with maximum range of GD were present, it was a better predictor for some traits.
Quantitative Trait Loci Controlling Leaf and Tassel Traits in a B73 × Mo17 Population of Maize
Authors: Mickelson S. M. , Stuber C. S. , Senior L. , Kaeppler S. M. 
Published: July 2010

ABSTRACTLight penetration into the canopy of maize (Zea mays L.) production fields is an important determinant of grain yield. Factors affecting light penetration include agricultural practices such as planting density and plant morphological factors such as leaf angle, leaf size, and tassel size. The objectives of this experiment were to identify genomic regions controlling the inheritance of leaf angle and tassel morphology in a B73 × Mo17 recombinant inbred population. Three quantitative trait loci (QTL) for tassel branch angle were detected which explained 35.6% of the phenotypic variation. Six QTL were detected for tassel branch number with three of these QTL on chromosome 2. Nine QTL were detected for leaf angle in one or more environments. Significant phenotypic correlations were detected between tassel branch angle and tassel branch number and between tassel branch number and leaf angle. Overlapping support intervals were identified between QTL detected for leaf angle and for tassel branch number on chromosome 2 near marker umc53a. Additionally, a QTL near marker bnl6.10 on chromosome 5 identified for tassel branch angle was in the same region as a QTL identified for leaf angle. The results of this study indicate that common genetic relationships exist between tassel traits and leaf angle.
Alignment of Lipid Bodies along the Plasma Membrane during the Acquisition of Desiccation Tolerance in Maize Seed
Authors: Cordova‐Tellez Leobigildo , Burris Joseph S. 
Published: July 2010

ABSTRACTThe impairment of lipid body alignment along the plasma membrane during artificial drying of maize (Zea mays L.) seed has been associated with decreases in germination and vigor. In this study, we question further its potential functions as well as the alignment mechanisms. Ears of hybrid maize [B73 × (H99 × H95)] were harvested at about. 550, 500, 400, and 320 g H2O kg−1 fresh weight (fw) and subjected to preconditioning (PC) (ear drying at 35°C and 0.47 m s−1 airflow rate) for 0, 12, 24, 36, and 48 h before fast drying (shelled seed, 35°C and 5.10 m s−1 airflow rate) treatments to decrease seed moisture content (MC) to about 130 g H2O kg−1 fw. In a cross section of the embryo radicle, alignment of lipid bodies (LB) occurred first in the root cap, followed by outer quiescent center (QC) cells and inner QC cells. This alignment pattern was observed during PC and under field drying conditions. Cell plasmolysis and aberrations of the LB were evident in seed harvested at MC > 400 g H2O kg−1 fw and subjected to fast drying without PC. Lipid body aberrations decreased in severity with PC, seed development, and field drying. The alignment of LB coincided with changes in embryo‐drying rates. Decreases in lipid body aberrations coincided with decreases in cell solute leakage and shoot/root ratio and increases in germination percentage. We conclude that alignment of LB along the plasma membrane is a progressive process that occurs from the periphery to the inner QC cells of the embryo radicle. Alignment of LB along the plasma membrane may change cell water relations leading to a more organized dehydration during seed drying. High embryo drying rates may prevent alignment of LB along the plasma membrane and are associated with low germination and vigor.
Green Leaf Chemistry of Various Turfgrasses
Authors: Johnson Albert W. , Snook Maurice E. , Wiseman Billy R. 
Published: July 2010

ABSTRACTSix grass species (zoysiagrass, bermudagrass, centipedegrass, tall fescue, St. Augustinegrass, and Kentucky bluegrass) were analyzed for polyphenols and flavonoids by high performance liquid chromatography. Each gave a characteristic leaf chemistry profile that allowed it to be differentiated from the other grasses. ‘Emerald’ zoysiagrass was characterized by the presence of chlorogenic acid and a group of luteolin‐glycosides containing glucose and/or arabinose. ‘Tifgreen’ bermudagrass contained no chlorogenic acid, and at least two of the flavonoids were apigenin‐glycosides in addition to several luteolin‐glycosides. Common centipedegrass and Ky 31 tall fescue both contained high levels of chlorogenic acid, but their flavonoid composition was different. Centipedegrass contained luteolin‐type flavonoid‐glycosides and maysin, an unusual luteolin‐diglycoside that possesses a unique keto‐sugar. Tall fescue contained quercetin‐type flavonoids rather than luteolin. Rutin was found as a major constituent of tall fescue. ‘Kenblue’ Kentucky bluegrass and ‘Raleigh’ St. Augustinegrass contained no chlorogenic acid. These two grasses contained several luteolin‐glycosides but not the broad, multiple flavonoid profiles of zoysiagrass and bermudagrass. Fall armyworm [FAW; Spodoptera frugiperda (J.E. Smith)] larval growth was significantly affected by the type of grass they fed upon in laboratory no‐choice tests. Fall armyworm larval weight reductions (as a percentage of the bermudagrasses) at 7 d after infestation were 90, 79, and 29% for zoysiagrass, centipedegrass, and St. Augustinegrass, respectively. Chlorogenic acid, luteolin, and the flavonoid‐glycosides rutin, maysin, and isoorientin were highly active in a laboratory bioassay in reducing FAW larval weights; however, no correlations could be made between FAW resistance and the levels of chlorogenic acid, flavonoids, or total phenolics extractable from the grasses evaluated.
Developing a Mini Core of Peanut for Utilization of Genetic Resources
Authors: Upadhyaya Hari D. , Bramel Paula J. , Ortiz Rodomiro , Singh Sube 
Published: July 2010

ABSTRACTPeanut (Arachis hypogaea L.) breeding programs with a goal of rapid cultivar development have used mainly elite breeding lines and cultivars, which has resulted in the development of breeding materials with a narrow genetic base. Utilization of exotic germplasm resources in breeding programs is needed to enhance the diversity of cultivars. Scientific plant breeding and its need for large variability, concern about potential loss of variability, and nonavailability of low cost tools to identify similarities or differences among accessions led genebanks to hold large germplasm collections. Core collections, generally contain about 10% of total accessions, represent the genetic variability of entire germplasm collection, and have been suggested as a way to enhance use of genetic resources in crop improvement. The objective of this study was to develop a peanut mini core subset. The peanut core subset was evaluated for morphological, agronomic, and quality traits in the rainy and postrainy seasons. Ward's method of clustering was used to separate core collection accessions into groups of similar accessions. A mini core subset consisting of 184 accessions was selected. Newman Keuls' test for means, Levene's test for variances, and chi‐square test for frequency distribution analysis for different traits indicated that the variation available in the core collection has been preserved in the mini core subset. This mini core subset will enhance exploitation of peanut genetic resources.
Application of fluorescence microscopy and image analysis for quantifying dynamics of maize pollen shed
Authors: Fonseca Agustin E. , Westgate Mark E. , Doyle Robert T. 
Published: July 2010

ABSTRACTThe objective of this study was to develop a simple, rapid and accurate technique to quantify maize (Zea mays L.) pollen shed under field conditions, capitalizing on the capacity of pollen to fluoresce and recent improvements in microscopic methods for acquiring, processing, and analyzing fluorescence signals from biological systems. Pollen shed naturally by the tassels was captured daily on passive pollen traps placed at apical ear level. Fluorescence microscopy was used to generate digital images of the trapped pollen, and pollen density per unit area was counted using commercial imaging software. Visual confirmation of fluorescing pollen grains indicated high measurement accuracy (r2 = 0.99) for the entire range of pollen shed densities typically encountered in the field. Pollen was randomly distributed across the surface of the pollen trap, and six to eight images per trap provided greater than 95% confidence for the mean trap value. The entire process of sample preparation, image capture, and image counting required less than 6 min per trap. The accuracy and ease of use of this technique make it ideal for characterizing the pattern of maize pollen production and dispersal under field conditions.
Plant Growth Regulators Alter Kentucky Bluegrass Canopy Leaf Area and Carbon Exchange
Authors: Beasley Jeffrey S. , Branham Bruce E. , Spomer L. Arthur 
Published: July 2010

ABSTRACTTurf managers apply plant growth regulators (PGRs) throughout the growing season to reduce clipping production, provide a uniform canopy, and increase color. Reduced efficacy of trinexapac‐ethyl (TE) [4‐(cyclopropyl‐α‐hydroxy‐methylene)‐3,5‐dioxocyclohexanecarboxylic acid ethyl ester] and paclobutrazol (PAC) [(2RS, 3RS)‐1‐(4‐chlorophenyl)‐4,4‐dimethyl‐2‐(1H‐1,2,4‐triazol‐1‐yl) pentan‐3‐ol] has been reported during warmer summer months. Plant growth regulator dissipation and Kentucky bluegrass (KBG; Poa pratensis L.) clipping production, canopy leaf area, and carbon exchange rates (CERs) were measured following single TE or PAC applications applied at three rates and three application timings. Warmer summer conditions reduced the intensity and duration of TE and PAC growth suppression compared to spring applications. Plant growth regulator applications above the manufacturers label rate provided no additional suppression. Residues of PGRs were analyzed by HPLC‐UV. Warmer temperatures increased TE and PAC uptake, but accelerated the rate of PGR dissipation. Carbon exchange rates were measured weekly on ground (CERG) and leaf (CERL) area bases. Treatment with PGRs resulted in decreased leaf area early during inhibition followed by increased rate of leaf area production. Changes in canopy leaf area were greatest in spring and PAC caused the greatest change in leaf area. Changes in CERG reflected changes in leaf area. Paclobutrazol generally increased CERL during periods of clipping suppression, while TE had no effect on CERL.
Genetic Enhancement of Resistance to Alternaria Leaf Blight in Sunflower through Cyclic Gametophytic and Sporophytic Selections
Authors: Rani T. Shobha , Ravikumar R. L. 
Published: July 2010

ABSTRACTOnly partial resistance has been reported so far in Helianthus species for leaf blight caused by Alternaria helianthi (Hansf.). Therefore, in the present study one to two cycles of recurrent selection based on sporophytic and gametophytic selection was effected to increase resistance to leaf blight in the base population. The base population was synthesized by random mating five diverse early generation breeding lines. The gamete selection was practiced by applying pathogen culture filtrate to stigma and style 1 h before pollination. The selection response was measured by recording observations on percent disease index (PDI) at flowering, 15 d after flowering and at physiological maturity. In both gametophytic and sporophytic selection cycles significant reduction in PDI was observed. The populations improved through gametophytic selection were more promising as the pollen selection could allow high selection intensity and absence of dominance effects. In sporophytic selection the rare favorable allelic combination is hardly detected. The progress in resistance in two cycles of selection was not very high for their use in crop improvement. There is a need to increase the number of cycle of selection to maximize the desirable alleles to achieve high level of resistance. The gametophytic selection combined with the conventional sporophytic selection can be considered as an effective tool in improving populations for partial resistance.
Response to Recurrent Selection for Resistance to Striga hermonthica (Del.) Benth in a Tropical Maize Population
Authors: Menkir A. , Kling J. G. 
Published: July 2010

ABSTRACTStriga hermonthica (Del.) Benth is an obligate root parasite infecting maize (Zea mays L.) and causing considerable yield losses in Africa. Few studies have been conducted to determine the effectiveness of recurrent selection for improving resistance to S. hermonthica in maize. The objective of this study was to evaluate genetic gain achieved in a composite subjected to six cycles of selection under S. hermonthica infestation. The selection cycles and checks were evaluated with and without S. hermonthica infestation at two locations in Nigeria for 2 yr. Selection for improved performance under S. hermonthica infestation significantly increased grain yield by 24% cycle‐1 and ears per plant by 9% cycle‐1. At the same time, the gain per cycle was −7% for relative yield loss, −5% for host damage rating, −9% for emerged S. hermonthica plants, −4% for anthesis–silking interval, and −5% for ear aspect. Selection under S. hermonthica infestation was accompanied by a concomitant increase in grain yield and improvement in plant aspect and ear aspect without S. hermonthica infestation. The observed progress in performance under S. hermonthica infestation demonstrates the effectiveness of recurrent selection for increasing polygenetic resistance against the parasite in tropical populations.
Peroxidase Gene Polymorphism in Buffalograss and Other Grasses
Authors: Gulsen O. , Shearman R. C. , Heng‐Moss T. M. , Mutlu N. , Lee D. J. , Sarath G. 
Published: July 2010

ABSTRACTPlant peroxidases are a family of related proteins possessing highly conserved domains. Degenerate oligonucleotide primers based on these conserved domains can be used to amplify DNA sequences coding for peroxidases from plants with unsequenced genomes. Polymorphisms in peroxidase genes among buffalograss [Buchloe dactyloides (Nutt.) Engelm.] genotypes and eight other grasses were evaluated, and potential evolutionary relationships were deduced using this approach. Fourteen peroxidase specific primers with alternative forward and reverse primers using 34 rice peroxidase cDNAs were designed based on conserved motifs of this gene family. Targeted polymerase chain reaction (PCR) amplification of genomic DNA from 28 buffalograss, 4 C4, and 4 C3 grass genotypes yielded polymorphisms, differentiating diploids from polyploids within buffalograss and C3 and C4 grass species from each other. A total of 11 peroxidase gene fragments, 7 belonging to buffalograss and 4 to the other grass species, were sequenced. Five of these sequences were clustered with rice (Oryza sativa L.) ascorbate peroxidase known to have chloroplast origin. These results demonstrate that primers targeting the peroxidase gene family can be used to study genotypic diversity and evolutionary relationships on an intraspecific and interspecific basis. The PCR‐based peroxidase markers may also have potential for linkage mapping and differential gene expression studies in grasses.
Evaluating Traffic Stress by the Brinkman Traffic Simulator and Cady Traffic Simulator on a Kentucky Bluegrass Stand
Authors: Vanini J. T. , Henderson J. J. , Sorochan J. C. , Rogers J. N. 
Published: July 2010

ABSTRACTThe Brinkman Traffic Simulator (BTS) has been a useful tool to simulate sports field traffic. However, rate of traffic stress produced by the BTS, a pull‐behind unit with two differentially connected studded rollers, has been questioned. The Cady Traffic Simulator (CTS), a modified walk‐behind core cultivation unit, was developed and tested to potentially produce more aggressive traffic stress. A comparison study was initiated between the BTS and CTS to evaluate these simulators on a Kentucky bluegrass (Poa pratensisL.) stand. Playing surface data collected were surface hardness, traction, soil moisture, bulk density, porosity, and plant counts. Higher surface hardness, lower traction, and lower plant count values resulted when the CTS applied 10 passes per week (PPW) compared with other treatments. Surface hardness, traction, and bulk density values were statistically similar when the CTS applied 2 PPW, and BTS applied 10 PPW.