Life Sciences Commons^™

Field Reaction Of Landrace Components Of Red Mottled Common Bacterial Blight, James S. Beaver, James R. Steadman, Dermot P. Coyne

Department of Agronomy and Horticulture: Faculty Publications

Field reaction of 25 red mottled bean ( Phaseolus vulgaris L.) genotypes to common bacterial blight [Xanthomonas campestris pv. phaseoli (Smith) Dye] was evaluated in Puerto Rico over 2 years. The average disease severity (percent leaf area with symptoms) was similar over years. The determinate red mottled genotypes had almost twice as much disease as indeterminate genotypes. Eight of the indeterminate genotypes had significantly less disease than the mean of the field experiments. These genotypes may serve as useful sources of resistance to common bacterial blight. The size of the chlorotic zone around necrotic lesions varied between growing seasons, …

Pathogenicity Of Pseudomonas Gladioli Pv. Gladioli On Rhizomatous Iris And Its Possible Role In Iris Scorch, Annie L. Wrobel, John E. Watkins, Don Steinegger

Department of Agronomy and Horticulture: Faculty Publications

Scorch of rhizomatous iris, Iris spp., occurs throughout much of the United States (Black, 1984). It is characterized as a rustcolored browning that starts on the tips of the youngest leaves in the center of the fan. Leaf necrosis progresses downward on the leaves and outward on the fan until the entire fan is affected. Roots shrivel and decay. Root cortical tissue completely deteriorates, but the epidermis and stele remain intact. The rhizome appears unaffected (Wadekamper, 1972).

Because of the sporadic occurrence of scorch and the difficulty of artificially reproducing scorch symptoms, little is known about the etiology, epidemiology, or …

Methyl Jasmonate Inhibition Of Root Growth And Induction Of A Leaf Protein Are Decreased In An Arabidopsis Thaliana Mutant, Paul E. Staswick, Wenpei Su, Stephen H. Howell

Department of Agronomy and Horticulture: Faculty Publications

Jasmonic acid and its methyl ester, methyl jasmonate (MeJA), are plant signaling molecules that affect plant growth and gene expression. Primary root growth of wild-type Arabidopsis thaliana seedlings was inhibited 50% when seedlings were grown on agar medium containing 0.1 μM MeJA. An ethyl methanesulfonate mutant (jar1) with decreased sensitivity to MeJA inhibition of root elongation was isolated and characterized. Genetic data indicated the trait was recessive and controlled by a single Mendelian factor. MeJA induced polypeptides were detected in Arabidopsis leaves by antiserum to a MeJA-inducible vegetative storage protein from soybean. The induction of these proteins by …

Jasmonate, Genes, And Fragrant Signals, Paul E. Staswick

Department of Agronomy and Horticulture: Faculty Publications

Although first recognized for its growth-inhibiting activity about 20 years ago, JA² and its fragrant methyl ester MeJA (referred to here collectively as jasmonate) are receiving renewed interest as potentially important signaling molecules in plants. This is because jasmonate markedly increases the expression of specific plant genes, some of which are wound responsive. Similarities with fatty acid-derived stress signaling molecules in animals (1) make jasmonate of general biological interest.

Describing And Quantifying Growth Stages Of Perennial Forage Grasses, K. J. Moore, Lowell E. Moser, Kenneth P. Vogel, Steven S. Waller, B. E. Johnson, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

A system for identifying and quantifying the stages of growth and development of perennial forage grasses was developed. The system consists of a universal set of morphological descriptors for forage and range grasses and a continuous numerical index. The life cycle of individual grass tillers is divided into five primary growth stages (i) germination, (ii) vegetative, (iii) elongation, (iv) reproductive, and (v) seed ripening. Substages corresponding to specific morphological events are defined within each primary stage. Each growth stage consists of a primary and secondary stage and has both a mnemonic code and numerical index associated with it. The codes …

Registration Of 'Trailblazer' Switchgrass, K. P. Vogel, Francis A. Haskins, Herman J. Gorz, B. A. Anderson, J. K. Ward

Department of Agronomy and Horticulture: Faculty Publications

'Trailblazer' switchgrass (Panicum virgatum L.) (Reg. no. CV-146, PI 549094) was developed by the USDA-ARS and the Nebraska Agricultural Research Division, Department of Agronomy, University of Nebraska, and released in 1984 for use as a warm-season pasture grass in the Central Great Plains and adjacent midwestern states.

Seed Weight Influence On Seedling Hydrocyanic Acid Potential In Sorghum, J. F.S. Lamb, Francis A. Haskins, Herman J. Gorz, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

Grain sorghum [Sorghum bicolor (L.) Moench) typically produces larger seeds than sudangrass [S. bicolor, formerly S. sudanense (Piper) Stapf); and grain sorghum seedlings are higher in hydrocyanic acid potential (HCN-p) than sudangrass seedlings. Previous studies have shown a seed-parent effect on seed weight and HCN-p in reciprocal F₁ hybrids of sorghum X sudangrass. This study was conducted to determine whether the seed-parent effect on HCN-p could be attributed primarily to the difference in seed size between reciprocal sorghum X sudangrass hybrids. Large and small seeds of low-HCN-p sudangrass, high-HCN-p sorghum, and their reciprocal hybrids, were visually …

Relative Environmental Adaptation Of Bell Pepper Cultivars Across Three Southeastern States [Abstract], Laurie Hodges, Douglas C. Sanders, Katharine B. Perry

Department of Agronomy and Horticulture: Faculty Publications

Four commercially available bell pepper cultivars (Capsicum annum L.) were evaluated for yield stability over a combination of 3 years, 3 planting dates, and 7 locations across the Carolinas and Georgia.

Defoliation Effects On Yield And Bud And Tiller Numbers Of Two Sandhills Grasses, J. Jeffrey Mullahey, Steven S. Waller, Lowell E. Moser

Department of Agronomy and Horticulture: Faculty Publications

Intensive grazing strategies for the Nebraska Sandhills must be based on time and frequency of defoliation of key warm-season grasses. A 3-year field study was conducted in the Nebraska Sand-hills to determine the effects of defoliation on yield and bud and tiller number of sand bluestem [Andropogon gerardii var. paucipilus (Nash) Fern.] and prairie sandreed [Calamovilfa longifolia (Hook.) Scribn.]. Defoliation (7 cm) treatments imposed on a 1.5 X 1-m plot were: a single defoliation on 10 June, 10 July, or 10 August; 2 successive defoliations on 10 June and 10 August; or 3 successive defoliations on 10 June, …

Inheritance Of Acid-Soil Tolerance In Sorghum (Sorghum Bicolor) Grown On An Ultisol, C. I. Flores, L. M. Gourley, Jeffrey F. Pedersen, R. B. Clark

Department of Agronomy and Horticulture: Faculty Publications

Inheritance of acid-soil tolerance (generally considered AI-toxicity tolerance) i.n sorghum [Sorghum bicolor (L.) Moench] is not clear. Forty F₁ sorghum hybrids and their 14 parents were grown two seasons in the field at relatively high (67 and 71%) and low (43 and 42%) Al saturations on an acid Ultisol in Colombia, South America to evaluate the effects of acid soil on agronomic component traits and to better understand inheritance of acid-soil tolerance of sorghum. For plants grown at the high Al saturation levels, hybrids from acid-soil tolerant [AS-T] x acid soil-sensitive [AS-S] crosses were as tolerant as hybrids from …

Nitrogen And Methyl Jasmonate Induction Of Soybean Vegetative Storage Protein Genes, Paul E. Staswick, Jing-Feng Huang, Yoon Rhee

Department of Agronomy and Horticulture: Faculty Publications

Vegetative storage protein (VSP) and VSP mRNA levels in soybean (Glycine max) leaves correlated with the amount of NH₄NO₃ provided to nonnodulated plants. The mRNA level declined as leaves matured, but high levels of N delayed the decline. This is consistent with the proposed role for VSP in the temporary storage of N. Wounding, petiole girdling, and treatment with methyijasmonate (MeJA) increased VSP mRNA in leaves 24 hours after treatment. The magnitude of the response depended on leaf age and N availability. N deficiency essentially eliminated the response to wounding and petiole girdling. MeJA was …

Notes: Interpretive Analysis For Forage Yield Trial Data, Jeffrey F. Pedersen, K. J. Moore, Edzard Van Santen

Department of Agronomy and Horticulture: Faculty Publications

Forage cultivar evaluation is often done in small plots with multiple harvests throughout the growing season. Data is often summarized by presenting a yearly total yield for each cultivar in addition to the mean for each harvest date. Data summarization often becomes burdensome and difficult to interpret. Regressing yield against a growth index associated with harvest dates can be utilized to describe forage performance in a concise and easily interpreted format. Subsets of data from tall fescue (Festuca amndinacea Schreb.) yield trials conducted in Alabama and Kentucky were used to demonstrate the technique. The analysis involves regressing yield of a …

‘Starlight’ —Great Northern Dry Bean, D.P. Coyne, James R. Steadman, Dale T. Lindgren, D.S. Nuland

Department of Agronomy and Horticulture: Faculty Publications

The release of ‘Starlight’, a Great Northern dry bean cultivar (Phaseolus vulgaris L.), fulfills a need in western Nebraska for a cultivar with a relatively large seed size and a uniformly bright-white seedcoat (Korban et al., 1981). Foreign buyers of Great Northern beans desire a larger seed than the current predominant Great Northern cultivar Beryl (J.A. McGill, Jr., personal communication). In addition, the cultivar possesses improved architectural avoidance mechanisms to white mold disease (WMD) incited by Sclerotinia sclerotiorum (Lib.) de Bary (Coyne, 1980), a serious problem in some seasons in western Nebraska.

Origin

‘Starlight’ (evaluated as F₁₀ WM1-85-43) …

Plant Production Cost-Accounting/ Management System, Kevin C. Power, Jay Fitzgerald, George Meyer, Dennis D. Schulte

Department of Agronomy and Horticulture: Faculty Publications

A microcomputer program has been developed to keep records on energy, labor costs, product pricing, and revenue predictions for greenhouse and nursery production. The program manages plant production data, potentially enabling the grower to improve production and profits. The grower can use the program to determine how much it costs to produce individual plants, to ascertain labor costs and where to reallocate employees. Advertising and other indirect costs can be included to determine cost of production on a per-plant or per-square-foot basis.

Medium Ph And Leaf Nutrient Concentration Influence Rust Pustule Diameter On Leaves Of Dry Beans, Haytham Z. Zaiter, Dermot P. Coyne, Ralph Clark, James R. Steadman

Department of Agronomy and Horticulture: Faculty Publications

Nine bean cultivars/lines (Phaseolus vulgaris L.) were grown in three soils/ rooting media at pH values of 7.9, 6.5, and 5.8 in greenhouse, growth chamber, and field experiments to evaluate the leaf reaction of the plants to a Nebraska bean rust [Uromyces appendiculatus (Pers.) Unger var. appendiculatus] isolate US85-NP-10-1. Significant differences were observed for rust pustule diameter between cultivars/lines grown in the three growth media. Plants grown in the medium at pH 5.8 showed significantly larger rust pustule diameters than those of plants grown at pH 6.5 or 7.9. A significant interaction occurred between growth medium and …

Effect Of Preemergence Herbicide On Wildflower Establishment, K.S. Erusha, C. Fricker, Bob Shearman, Don Steinegger

Department of Agronomy and Horticulture: Faculty Publications

This study was initiated to evaluate wildflower establishment using a preemergence herbicide. Fifty species of wildflowers (Table 1) were established on a Sharpsburg silty-clay loam (Typic Argiudoll), with a 6.9 pH, near Mead, Neb. Fortyseven (Table 1) wildflowers were established near Hubbard, Ore., on a Willamette sandy loam (Pachic Ultic Argixeroll) with a 6.6 pH. Both studies used a split-plot design, with herbicide treatment as main plots and wildflowers as subplots. Each treatment consisted of two replicates.

Herbicide treatments included an untreated control and a combination of S-ethyl dipropylthiocarbamate (EPTC) at 2.3 kg·ha-1 and α, α, α -trifluoro-2,6-dinitro-N,N-dipropyl-ptoluidine (trifluralin) at …

Monofilament Lines Fail To Protect Grapes From Bird Damage, Don Steinegger, Danilo A. Agüero, Ron J. Johnson, Kent M. Eskridge

Department of Agronomy and Horticulture: Faculty Publications

Birds feeding on horticultural crops may cause extensive losses, but control techniques currently available are not always practical or otherwise appropriate. Control of certain birds is attempted by placing widely spaced lines or wires over or around sites needing protection (Pochop et al., 1990). Recently, Knight (1988) reported observations that monofilament lines could be used to protect various horticultural crops, including grapes, from bird damage. However, more closely controlled research was needed to better quantify effectiveness of this technique for various bird species. The objectives of this study were to determine the effectiveness of monofilament lines in protecting ripening grapes …

Fertility And Forage Yield Of Sorghum X Sudangrass Hybrids In A1 And A3 Cytoplasm, J. J. Toy, Jeffrey F. Pedersen, K. J. Moore

Department of Agronomy and Horticulture: Faculty Publications

Most sorghum x sudangrass hybrids are currently produced in Al male-sterile cytoplasm. Availability of alternative cytoplasmic sterility systems allows production of sorghum x sudangrass hybrids that may have superior forage characteristics. A study was conducted to compare the agronomic performance of Al and A3 sorghum x sudangrass hybrids. A bulk of eight sudangrass populations was used to pollinate four grain sorghum inbreds normally used as females that had been sterilized in both Al and A3 cytoplasm, and two inbreds normally used as males that had been sterilized in A3 cytoplasm. The hybrids were evaluated in 1990. Results indicate that male-sterile …

Defoliation Effects On Production And Morphological Development Of Little Bluestem, J. J. Mullahey, Lowell E. Moser, Steven S. Waller

Department of Agronomy and Horticulture: Faculty Publications

Response of key warm-season grasses to time, frequency, and duration of defoliation is needed to develop grazing systems for the Nebraska Sandhills. A 3- year (1986 to 1988) study was conducted on a Valentine fine sand (mixed, mesic Typic Ustipsamments) at the Gudmundsen Sandhills Laboratory near Whitman, Nebraska, to determine the effect of defoliation on little bluestem [Schizachyrium scoparium (Michx.) Nash]. Treatments were: 1 defoliation (to 7 cm) on 10 June, 10 July, or 10 Aug.; 2 defoliations on 10 June and 10 Aug.; and 3 defoliations on 10 June, 10 July, and 10 Aug. Control plants were harvested …

Warm-Season Grass Establishment As Affected By Post-Planting Atrazine Application, C. C. Bahler, Lowell E. Moser, T. Griffin, Kenneth P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

Atrazine [6-chloro-N-ethyl-N’-methylethyl)-1,3,5-triazine-2,4-diamine] provides effective weed control during big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatrum L.) establishment. However, most other desirable warm-season grasses are susceptible to atrazine injury at establishment. The objective of this study was to determine if atrazine applications after seedling would affect susceptible warm-season grass establishment. Big bluestem, switchgrass, Indiangrass [Sorghastrum nutans (L.) Nash], sideoats grama [Bouteloua curtipendula (Michx.) Torr.], and little bluestem [Schizachyrium scoparium (Michx.) Nash] were needed into greenhouse flats or field plots and 2.2 kg a.i. atrazine/ha applied at 0 (atrazine control), 7, 14, or 21 days after …

Registration Of 10 Sudangrass Inbred Lines, Herman J. Gorz, Francis A. Haskins, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

Ten pairs of A and B (male-sterile and maintainer) inbred lines (N112 to N121, Reg. no. GP 261 to 270, PI 535797 to 535806)of sudangrass [Sorghum bicolor (L.) Moench] [formerly S. sudanense (Piper) Staph] were developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division and were released in April 1989. The major objective in the development of these lines was reduction in hydrocyanic acid potential (HCN-p) to facilitate the production of sudangrass hybrids low in HCN-p. While good progress in lowering HCN-p has been made in most lines, some still exceed the level found in 'Piper' sudangrass …

Registration Of 15 Germplasm Lines Of Grain Sorghum And Sweet Sorghum, Herman J. Gorz, Francis A. Haskins, B. E. Johnson

Department of Agronomy and Horticulture: Faculty Publications

Four inbred lines (N97-N100) and 11 pairs of A and B (male-sterile and maintainer) lines (N101-N111) of sorghum [Sorghum bicolor (L.) Moench] were developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division and were released in April 1989. The lines contain one or more traits that may have value for use in producing hybrids and/or conducting breeding and management studies. All A-lines have milo (A1) cytoplasm.

Registration Of Np36 And Np37, Two Random-Mating Grain Sorghum Populations Selected For Reduced Dhurrin Content, Herman J. Gorz, Francis A. Haskins, B. E. Johnson, A. Sotomayor-Rios

Department of Agronomy and Horticulture: Faculty Publications

NP36 and NP37 grain sorghum [Sorghum bicolor (L.) Moench] (Reg. no. GP-244 and GP-245; PI 535780 and PI 535781), two random-mating populations of grain sorghum, were developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division and were released in April 1989. Both populations were selected for reduced dhurrin content, and they have potential value as sources of A- and B-lines of grain sorghum for use in producing low-dhurrin sorghum-sudangrass hybrids. NP37 also contains the bmr-6 gene for brown midribs and, therefore, may be useful in producing sorghum-sudangrass or forage sorghum hybrids with brown midribs.

Registration Of Np33 Np34 And Np35 Three Broadly Based Random-Mating Populations Of Sudangrass, Herman J. Gorz, Francis A. Haskins, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

NP33, NP34, and NP35 Sudangrass [Sorghum bicolor (L.) Moench] [formerly S. sudanense (Piper) Staph] (Reg. no. GP-241, GP-242, and GP-243; PI 535777, PI 535778, and PI 535779) are three related random-mating populations that were developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division and were released in April 1989. These populations represent a broad range of genetic diversity for a variety of agronomic traits and dhurrin level, and NP34 and NP35 contain the ms₃ gene for male sterility.

Registration Of Np31 And Np32 Two Populations Of Sudangrass Selected For Low Dhurrin Content, Francis A. Haskins, Herman J. Gorz, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

NP31 and NP32 sudangrass [Sorghum bicolor (L.) Moench] [formerly S. sudanense (Piper) Staph] (Reg. no.GP-239 and GP-240; PI 535775 and PI 535776), two populations developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division, were released in April 1989. These populations are potential sources of low-dhurrin germplasm for public and private sudangrass breeding programs. NP31 also contains the ms₃ gene for genetic male sterility and NP32 may be a source of sudangrass B-lines.

Registration Of Np30, A Low-Dhurrin Sudangrass Population Selected For Regrowth Potential, Herman J. Gorz, Francis A. Haskins, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

NP30 sudangrass [Sorghum bicolor (L.) Moench] [formerly S. sudanense (Piper) Staph] (Reg. no. GP-238, PI 535774) is a low-dhurrin, random-mating population developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division. The population was released in April 1989. NP30 was synthesized from 85 S₁ families selected from a total of 757 families that were evaluated for regrowth potential. The germplasm sources evaluated included 50 S₁ families from the NP25(3) sudangrass population, 90 from NP28(2), 284 from NP29(4), 200 from NP31(5), 50 from NP32(5), and 83 S₁ families from miscellaneous breeding lines low in dhurrin. The …

Registration Of Np29, A Low-Dhurrin Sudangrass Population Selected For Tolerance To Early Spring Seeding, Francis A. Haskins, Herman J. Gorz, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

NP29 sudangrass [Sorghum bicolor (L.) Moench] [formerly S. sudanense (Piper) Staph] (Reg. no. GP-237, PI 535773) was developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division and was released in April 1989. Germplasm sources involved in the synthesis of this population included 10 low-dhurrin sudangrass populations, seven of which contained the ms₃ gene for genetic male-sterility. Included were NP23(2); NP25(3); NP32(4); three experimental populations that were composited to make up NP31(4); an unreleased population; and three populations representing Cycle 0, Cycle I, and Cycle 2 from an earlier selection experiment to improve tolerance to early spring …

Registration Of Np28 Sudangrass Germplasm, A Composite Of 90 Low-Dhurrin Self-Pollinated Lines, Herman J. Gorz, Francis A. Haskins, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

NP28 Sudangrass [Sorghum bicolor (L.) Moench] [formerly S. sudanense (Piper) Staph] (Reg. no. GP-236, PI 535772), a population developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division, was released in April 1989. NP28 is a composite consisting of equal quantities of seed of 90 low-dhurrin, highly self-pollinated lines of sudangrass. Each of the lines was derived by seven or more generations of selfing following one or more crosses among seven sources of sudangrass germplasm. The sources included low-dhurrin selections from 'Piper'; low-dhurrin breeding lines from the University of Wisconsin; two sudangrass B-lines (maintainers for A₁ cytoplasm) …

Adsorption Of The Herbicides Diuron, Terbacil, And Simazine To Blueberry Mulches, Laurie Hodges, Ronald E. Talbert

Department of Agronomy and Horticulture: Faculty Publications

Samples of soil, mulch, and the soil/mulch interface zone were collected from commercial highbush blueberry (Vaccinium corymbosum L.) fields typical in their use of mulch under Arkansas conditions. Mulches included J-year-old hardwood sawdust, 5-year-old hardwood sawdust, and 1-year-old pine needle mulch. Herbicide adsorption (Kd values) of the samples was determined for diuron, terbacil, and simazine. The soils, mulches, and interfaces adsorbed nearly 10 times as much diuron and more than twice as much simazine as terbacil. Adsorption of the herbicides was three to five times greater to the mulches than to the soils. Adsorption was significantly correlated with the …

Improvement Of Carrot Stands With Plant Biostimulants And Fluid Drilling, Douglas C. Sanders, Jacqueline A. Ricotta, Laurie Hodges

Department of Agronomy and Horticulture: Faculty Publications

We determined if application of certain naturally occurring compounds would stimulate emergence, growth, and development of carrot (Daucus carota L.). The commercially available biostimulants Agro-Lig, Enersol (humic acids), and Ergostim (folic acid) were added at a concentration of 1.5% (w/v) to Laponite 508 (magnesium sulfate) gel used in fluid drilling. Agro-Lig, Enersol and Ergostim increased carrot emergence >2-fold as measured by number of roots as compared to untreated seed. Number of carrots increased 50% to 75% when biostimulants were incorporated into the gel, compared to fluid-drilled seed without the biostimulants. When biostimulants were applied as a drench over untreated …