Life Sciences Commons^™

Using Leaf Fluorescence For Evaluating Atrazine Tolerance Of Three Perennial Warm-Season Grasses, Caroline Bahler, Lowell E. Moser, Kenneth P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

Atrazine [6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4-diamine] blocks photosymthetic electron transport in susceptible plants. The energy from the interrupted electron transport is fluoresced from the leaves of atrazine-treated plants. The purpose of this study was to evaluate leaf fluorescence as a nondestructive bioassay of the relative atrazine tolerance of 3 perennnial, warm-season grasses. Leaf section of switchgrass [Panicum virgatum L.] (high tolerance), indiangrass [Sorghastrum nutans (L.) Nash] (intermediate tolerance), and sideoats grama [Boutelouacurtipendula (Michx.) Torr.] (lower tolerance) were placed in distilled water for 20 minute and then in atrazine solutions. Fluorescence readings were taken prior to and after the atrazine treatment with …

Effect Of Herbicide Safeners On Sand And Little Bluestems, W. Roder, Steven S. Waller, James L. Stubbendieck, Lowell E. Moser, Alex Martin

Department of Agronomy and Horticulture: Faculty Publications

Weed competition is a major factor limiting establishment of warm-season grasses. Use of preemergence herbicides in conjunction with herbicide safeners can offer a successful weed control strategy. Effects of herbicide safeners applied as seed treatments, and soil-incorporated herbicides on sand bluestem [Andropogon gerardii var paucipilus (Nash) Fern.] and little bluestem [Schizachyrium scoparium (Michx.) Nash] were evaluated in germinator and greenhouse studies. The safeners cyometrinil ((Z)-[cyanomethoxy)imino] benzeneacetonitrile), dichlormid (2,2-dichloro-N,N-di-2-propenylacetamide), and R-29148 (2,2-dimethyl-6-methyldichloroacetyloxazolidine) reduced germination and shoot growth of both grasses. Sand bluestem was protected against EPTC (S-ethyl dipropyl carbamothioate) and vernolate (S-propyl dipropylcarbamothioate) by R-29148, …

Yield Accumulation, Leaf Area Index, And Light Interception Of Smooth Bromegrass, R. K. Engel, Lowell E. Moser, James L. Stubbendieck, S. R. Lowry

Department of Agronomy and Horticulture: Faculty Publications

Smooth bromegrass (Bromus inemis Leyss.) is a cool-season grass used extensively in the midwestern USA for spring and fall grazing. Smooth bromegrass has limited production in this region during the summer. This study was conducted to document the growth characteristics and yield accumulation of smooth bromegrass under various levels of N fertilizer. Live yield (dry matter yield of living herbage), leaf area index (LAI), light interception (LI), and crop growth rate (CGR) were determined on an established stand of 'Lincoln' smooth bromegrass grown on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic Typic Argiudolls) in eastern Nebraska. Zero, medium, …

Seasonal Variation In Leaf Hydrocyanic Acid Potential Of Low- And High-Dhurrin Sorghums, Francis A. Haskins, H. J. Gorz, B. E. Johnson

Department of Agronomy and Horticulture: Faculty Publications

The KSS and N32 sorghum [Sorghum bicolor (L.) Moench) lines are low and high, respectively, in the hydrocyanic acid potential (HCN-p) of mature leaves. This difference is conditioned primarily by a single pair of alleles. The main objective of this study was to determine, at various stages of plant growth and various times during the growing season, the HCN-p of upper leaves and tillers of field-grown plants of these two parental lines and of two low-HCN-p F F₃ lines derived from crosses between KS8 and N32. The four entries were grown in a randomized complete block design with …

Research And Development Strategies For A Sustainable Agriculture, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

"Food production and rural income are two prime concerns of Third World governments. Increased food production and greater food security are goals which countries strive to achieve through agricultural development. The technologies generated by research, commonly known as green revolution methods, have provided an impetus to food production in some favored zones where resources are available to take advantage of this production package. New varieties, productive and responsive to fertilizer, have bought time while countries work to control population growth and develop agriculture and industry" (Francis and Harwood, 1985).

The pioneering work of the International Agricultural Research Centers has been …

Combining Ability Effects For Mineral Elements In Forage Sorghum Hybrids, H. J. Gorz, Francis A. Haskins, Jeffrey F. Pedersen, W. M. Ross

Department of Agronomy and Horticulture: Faculty Publications

The concentrations of minerals in forages are important in satisfying animal requirements, but little attention has been given to determining these concentrations in forage sorghum (Sorghum bicolor (L.) Moench.) breeding programs. In this 2-yr study, the objectives were to determine the contents, genetic variability, combining ability effects, and correlations for 12 mineral elements in 49 experimental hybrids of forage sorghum. Mineral elements studied were N, Mg, Si, P, S, CI, K, Ca, Mn, Fe, Cu, and Zn. General combining ability (GCA) effects exceeded specific combining ability (SCA) effects for all elements except P, CI, and Fe in females, and …

Inheritance Of Seedling Hydrocyanic Acid Potential And Seed Weight In Sorghum-Sudangrass Crosses, J. F. S. Lamb, Francis A. Haskins, H. J. Gorz, Kenneth P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

The hydrocyanic acid potential (HCN-p) of sorghum (Sorghum Bicolor (L.) Moench] plants is recognized as a heritable trait, but previous studies on the mode of inheritance of HCN-p have produced inconsistent results. The objective of this study was to investigate the inheritance patterns of seedling HCN-p and also of seed weight in reciprocal crosses of sorghum and sudangrass (formerly S. sudanense (Piper) Stapf). Both traits were found to be inherited quantitatively. Generation means analysis indicated that additive genetic effects were most important for both seed weight (53% of variation) and seedling HCN-p (74% of variation). A maternal effect was …

Evaluation Of Repellent Seed Treatments And Effects On Early Corn Performance, Ann E. Koehler, Ron J. Johnson, Orvin C. Burnside, Stephen R. Lowry

Department of Agronomy and Horticulture: Faculty Publications

A combination of field, field enclosure, and germination chamber studies was used to evaluate the effects of methiocarb [3,5-dimethyl-4-(methylthio)phenol methylcarbamate] and thiram (tetramethylthiuram disulfide) repellent seed treatments on early corn performance. The thiram treatments used (0.08, 0.4,0.8,0.5,1.25, and 2.5% active ingredient by corn seed weight) had negligible effects on germination/emergence time or on com plant heights. The thiram treatments never reduced stand counts in comparison to controls, but apparently increased stand counts in some trials, particularly under wet conditions. The methiocarb treatments evaluated (0.5, 1.25, 2.5, and 5.0% active ingredient by corn seed weight) had only occasional effects on early …

A Temperature-Sensitive Chlorophyll B-Deficient Mutant Of Sweetclover (Melilotus Alba), John P. Markwell, Stephen J. Danko, Hermann Bauwe, John Osterman, Herman J. Gorz, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

The ch4 mutant of sweetclover (Melilotus alba) has previously been demonstrated to be partially deficient in chlorophyll and to have a higher ratio of chlorophyll a to b than normal plants. We were able to substantiate these findings when plants were grown at 23°C and lower (permissive temperatures). However, when grown at 26°C (nonpermissive temperature) the plants produced small yellow leaves which exhibited one-twentieth the chlorophyll content of normal plants. Affected leaves did not increase their chlorophyll content when plants were incubated at permissive temperatures, but leaves which developed at the lower temperature contained increased amounts of chlorophyll. …

Inheritance Of Leucoanthocyanidin Content In Sorghum Leaves, Francis A. Haskins, Herman J. Gorz

Department of Agronomy and Horticulture: Faculty Publications

Leucoanthocyanidins (LAC) are structurally related to condensed tannins, a class of compounds having significant effects on the nutritional value of sorghum [Sorghum bicolor (L.) Moench) grain. Little is known of LAC inheritance in sorghum. Mature leaves of 'Colman' and 'White Collier' forage sorghum are high and low, respectively, in LAC content. The objective of the present study was to determine the inheritance of LAC content in reciprocal crosses between these two cultivars, Leaves of field-grown plants were assayed for LAC by a procedure that involved treating methanolic leaf extracts with acid at 50°C to convert the colorless LAC to …

Development And Validation Of A Dynamic Model Of Growth And Quality For Cool Season Grasses, W. F. Brown, Lowell E. Moser, Terry J. Klopfenstein

Department of Agronomy and Horticulture: Faculty Publications

A daily time step model simulating growth and quality of cool season grasses was developed and validated for smooth brome (Bromus inermis Leyss.) under varying environmental and management conditions. Growth predictions are based upon genetic potential, environmental temperature, leaf area, soil moisture, and nitrogen fertilization rate. Daily potential growth rate is a composite of two functions—one relating grass species maximum growth rate to minimum, optimum, and maximum temperatures for plant growth, and another relating daily minimum and maximum air temperatures to time. Multipliers are developed for available leaf area, moisture, and nitrogen, and the minimum of these values modifies …

A Temperature-Sensitive Chlorophyll Β-Deficient Mutant Of Sweetclover (Melilotus Alba), John P. Markwell, Stephen Danko, Hermann Bauwe, John Osterman, Herman Gorz, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

The ch4 mutant of sweetclover (Melilotus alba) has previously been demonstrated to be partially deficient in chlorophyll and to have a higher ratio of chlorophyll a to b than normal plants. We were able to substantiate these findings when plants were grown at 23°C and lower (permissive temperatures). However, when grown at 26°C (nonpermissive temperature) the plants produced small yellow leaves which exhibited one- twentieth the chlorophyll content of normal plants. Affected leaves did not increase their chlorophyll content when plants were incubated at permissive temperatures, but leaves which developed at the lower temperature contained increased amounts of …

Evaluation Of Agronomic And Energy Traits Of Wray Sweet Sorghum And The N39 X Wray Hybrid, Max D. Clegg, H. J. Gorz, Jerry W. Maranville, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

Recent emphasis on energy problems has stimulated efforts to identify crops capable of producing high yields of biomass that can be converted into ethanol. The sorghum [Sorghum bicolor (L.) Moench] crop includes cultivars and hybrids that vary widely in the relative amounts of grain and stalks produced, and also in the sugar content of the stalks. N39 x Wray, a relatively sweet hybrid with good grain potential, and Wray, a cultivar with sweet stalks, were compared for their grain and sugar yields, alcohol production potential, and other related characters. The hybrid produced heavier seeds, more seeds per head, and …

Relationship Between Contents Of Leucoanthocyanidin And Dhurrin In Sorghum Leaves, Francis A. Haskins, Herman J. Gorz

Department of Agronomy and Horticulture: Faculty Publications

Flag leaves of 'Colman' forage sorghum (Sorghum bicolor) contain at least 25 times as much leucoanthocyanidin (LAC) and approximately half as much of the cyanogenic glucoside, dhurrin, as do flag leaves of 'White Collier' forage sorghum. Assays of flag leaves from 119 F2 plants and 11 F, lines from crosses between these two cultivars revealed a statistically significant negative association between levels of LAC and dhurrin. Both LAC and dhurrin are aromatic compounds, and the negative association between the two may be the result of competition for intermediates or products of the aromatic biosynthetic pathway. This rationale appears …

Inheritance Of Dhurrin Content In Mature Sorghum Leaves, Herman J. Gorz, Francis A. Haskins, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

Seedlings of both KS8 and N32 sorghum [Sorghum bicolor (L.) Moench] were high in dhurrin [p-hydroxy-(S)-mandelonitrile-β-D-glucoside] and thus in hydrocyanic acid potential (HCN-p), but the HCN-p of mature leaves from field-grown plants of KS8 was only about one-tenth as high as that of N32. A study of the inheritance of this large difference between KS8 and N32 revealed that a single major gene pair was responsible. There were no obvious maternal effects and F,'s were generally intermediate in HCN-p level between the two parents, indicating that neither high nor low HCN-p was completely dominant. HCN-p …

Registration Of Np25 Low-Dhurrin Sudangrass Germplasm, Francis A. Haskins, Herman J. Gorz, S. D. Kindler, S. G. Jensen, A. Sotomayor-Rios

Department of Agronomy and Horticulture: Faculty Publications

NP25 sudangrass [Sorghum bicolor (L.) Moench] (Reg. no. GP-180), a low-dhurrin, random-mating population that carries the ms₃ gene for genetic male sterility, was developed cooperatively by USDA-ARS and the Nebraska Agricultural Research Division and released in April 1984. Plants of NP25 are leafy and fine-stemmed, 160 to 170 cm in height with dry stalks (white midrib), tan plant color, sienna glumes, and brown pericarp. NP25 restores fertility to hybrids when crossed to male steriles with A1 cytoplasm.

Registration Of Np23 And Np24 Sudangrass Germplasms, Herman J. Gorz, Francis A. Haskins, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

NP23 and NP24 sudangrass [Sorghum bicolor (L.) Moench] (Reg. no. GP-178 and GP-179) populations, developed cooperatively by USDA-ARS and the Nebraska Agricultural Research Division, were released in April 1984. NP23 and NP24 were derived from 'Greenleaf by selection for lower and higher dhurrin content, respectively. Both populations resemble Greenleaf in general appearance with sweet, juicy culms (dull or green midribs), dark green color, late maturity, excellent leafiness and disease resistance, and both tan and purple plant color. Glume colors include black, mahogany, and sienna; pericarp color is brown. Glumes become detached from some of the seeds during threshing. In …

Growth And Magnesium Uptake Of Tall Fescue Lines At High And Low Potassium Levels, J. H. Edwards, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Five tall fescue (Festuca arundinacea Schreb.) clonal lines with diverse root and xylem diameters were grown in nutrient solutions with magnesium (Mg) concentrations of 42, 125 and 250 µm and potassium K concentrations of 133 and 333 µm. Leaf Mg concentrations increased with increasing Mg rates at both low and high K concentrations. The tall fescue line with the largest root and xylem diameters had low leaf Mg concentrations, indicating a possible increased Mg tetany potential when consumed by cattle. The response of the K/(Mg+Ca) ratio in the plant, an indicator of tetany potential, to varying solution Mg at low …

Viewpoint: Forage And Range Research Needs In The Central Great Plains, Kenneth P. Vogel, H. J. Gorz, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

In the central Great Plains, pastures and rangelands often are not economically competitive with grain crops. This has led to increases in acreages of row crops at the expense of rangelands, pastures, and hay crops on marginal lands resulting in severe erosion problems. The productivity of forages, pastures, and rangelands needs to be increased to levels that would make them economically competitive with grain crops. Innovative research will be needed to develop the required knowledge and technology upon which productivity increases can be based. Pastures and rangelands in this area are usually components of production systems which may also include …

Dhurrin And P-Hydroxybenzaldehyde In Seedlings Of Various Sorghum Species, Francis A. Haskins, H. J. Gorz

Department of Agronomy and Horticulture: Faculty Publications

Week-old shoots of 50 Sorghum entries representing 22 species, plus four Sorghum entries of undesignated species, were dried at 75° and the dried tissue extracted with water at room temperature. The resulting extracts were diluted in 0.1 M sodium hydroxide and spectra were scanned immediately to provide a measure of free p-hydroxybenzaldehyde. Scans were repeated after the basic solutions had stood for 3 hr at room temperature to permit hydrolysis of dhurrin (S-p-hydroxymandelonitrile β-D-glucopyranoside). Without exception, the quantity of free p-hydroxybenzaldehyde was very small in relation to the quantity released by dhurrin hydrolysis.

Response Of An Irrigated Cool- And Warm- Season Grass Mixture To Nitrogen And Harvest Scheme, Joseph L. Petersen, Lowell E. Moser

Department of Agronomy and Horticulture: Faculty Publications

Maintaining a mixture of cool-and warm-season grasses under intensive management for season-long production is difficult, due to species shifts, especially to a dominance of cool-season grasses when heavy amounts of nitrogen(N) fertilizer are used. The objective of this study was to determine if high forage yields could be produced season long while maintaining a desirable balance of warm-and cool-season grasses.

The study was conducted near Mead, Nebraska on a Sharpsburg silty clay loam (Typic Argiudoll). An irrigated mixture of 3 warmseason grasses and 1 cool-season grass, big bluestem (Andropogon gerardii Vitman), switchgrass (Panicum virgatum L.), and indiangrass [ …

Comparison Of F1'S And Inbreds As Female Parents For Sorghum-Sudangrass Seed Production, Herman J. Gorz, J. J. Toy, Francis A. Haskins, W. M. Ross

Department of Agronomy and Horticulture: Faculty Publications

Two field studies involving different groups of germplasm were conducted to compare sorghum-sudangrass, Sorghum bicolor (L.) Moench X S. sudanense (Piper) Stapf, hybrid seed production of male-sterile F₁'s with their component A-lines. The F₁'s yielded 45 and 82% more grain than their A-line counterparts in Study 1 and 2, respectively, with the increase attributable to more seeds per panicle and a greater threshing percentage. Mean values of nine traits measured on nine groups of eight F₁'s in Study 1 and seven groups of six F₁'s in Study 2 were compared with their …

Effect Of Freezing On The Hydrocyanic Acid Potential Of Field-Grown Sorghum Tillers, Francis A. Haskins, Herman J. Gorz, R. M. Hill, J. Brakke Youngquist

Department of Agronomy and Horticulture: Faculty Publications

Tissue disruption caused by freezing and thawing may contribute to rapid enzymatic breakdown of dhurrin [p-hydroxy-(S)mandelonitrile-β-D-glucoside], the cyanogenic glucoside of sorghum [Sorghum bicolor (L.) Moench], but published reports are not in agreement as to the effects of freezing on the hydrocyanic acid potential (HCN-p) of field-grown sorghum leaves. These effects were investigated in a series of experiments in the fan of 1983, a period during which weather conditions at Lincoln, NE, permitted repeated sampling of frozen and non-frozen leaves of field-grown sorghum tillers. Assays of these samples, both spectrophotometrically and with the cyanide electrode, indicated …

Atrazine Tolerance In Warm-Season Grass Seedlings, C. C. Bahler, Kenneth P. Vogel, Lowell E. Moser

Department of Agronomy and Horticulture: Faculty Publications

Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] effectively controls many annual weeds in established warm-season range grasses but can damage some of these grasses in the early seedling stage. This study determined the relative atrazine tolerance of seedlings of selected warm-season grasses and evaluated the effectiveness of a greenhouse bioassay for seedling atrazine tolerance in range gasses. Seed of 'Pathfinder' switchgrass [Panicum virgatum L.], 'Nebraska 54' indiangrass [Sorghastrum nutans (L.) Nash], 'Butte' side-oats grama [Bouteloua curtipedula (Michx.) Torr.], an experimental blue grama 'PMK 1483' [B. gracilis (H.B.K.) Lag ex Steud], 'Plains' bluestem (Bothriochloa ischaemum var ischaemum (L.) Keng), 'Caucasian' bluestem …

Influence Of Sample Treatment On Apparent Hydrocyanic Acid Potential Of Sorghum Leaf Tissue, Francis A. Haskins, Herman J. Gorz, R. M. Hill, J. Brakke Youngquist

Department of Agronomy and Horticulture: Faculty Publications

When dhurrin [p-hydroxy-(S)-mandelonitrile-β-D-glucoside], the cyanogenic glucoside of sorghum [Sorghum bicolor (L.) Moench], is hydrolyzed by autoclaving, p-hydroxybenzaldehyde (p-HB) is released. The spectrophotometric determination of p-HB concentration in autoclaved sorghum leaf extracts provides a measure of the hydrocyanic acid potential (HCN-p) of leaf tissue. Extracts of field-grown sorghum leaves contained substances that interfered with this procedure, but ether extraction effectively separated p-HB from these interfering materials. We observed that when flag leaf tissue from field-grown sorghum was dried at 75°C and then autoclaved, HCN-p values were about three times as high …

In Vitro And In Vivo Analyses Of Hays Of Switchgrass Strains Selected For High And Low In Vitro Dry Matter Digestibility, K. P. Vogel, R. Britton, Herman J. Gorz, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

In a previous report the progress made in altering the in vitro dry matter digestibility (lVDMD) of switchgrass (Panicum virgatum L.) in one cycle of divergent selection was described. In this study, the detergent system of analyses was used in an attempt to determine what plant constituents had been altered by the selection for IVDMD. Hays from five switchgrass strains differing in IVDMD harvested over a 3-year period were analyzed for protein content, neutral detergent fiber (NDF), acid detergent fiber (ADF), ash, and lignin. Although there were differences (p ≤ 0.05) among strains for IVDMD as determined by …

Registrationo F Np22 Sudangrass Germplasm, Herman J. Gorz, Francis A. Haskins, S. D. Kindler, A. Sotomayor-Rios

Department of Agronomy and Horticulture: Faculty Publications

'NP22' Sudangrass [Sorghum bicolor (L.) Moench] [formerly S. sudanense (Piper) Staph] (Reg. No. GPI38), a random-mating population carrying the mS3 gene and selected primarily for low dhurrin content, is generally similar in appearance to 'Piper' sudangrass with mostly dry stalks (white midrib) and purple plant color. Seed color is heterogeneous and includes straw, sienna, mahogany, and black glumes. NP22 was developed cooperatively by USDA-ARS and the Nebraska Agricultural Experiment Station and released in May 1982.

Leakage Of Dhurrin And P-Hydroxybenzaldehyde From Young Sorghum Shoots Immersed In Various Solvents, Francis Haskins, H. J. Gorz

Department of Agronomy and Horticulture: Faculty Publications

Spectral scanning was used to provide estimates of the leakage of the cyanogenic glucoside, dhurrin (p-hydroxy-[S]-mandelonitrle-β-D-glucoside) and its metabolite, p-hydroxybenzaldehyde (p-HB), from young light-grown shoots of Atlas sorghum (Sorghum bicolor [L.] Moench) when these shoots were immersed in water, toluene, chloroform or mixtures of water and toluene or water and chloroform. Minimal leakage of dhurrin and virtually no leakage of p-HB occurred with water as the solvent. The 0.5% concentration (v/v) of both toluene and chloroform was more effective than either the 1.0 or 2.0% concentrations in effecting leakage of the two solutes. With either 0.5% toluene or 0.5% …

Identification Of Chromosomes With Secondary Constrictions In Melilotus Species, S. E. Schlarbaum, L. B. Johnson, Herman J. Gorz, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

Secondary constrictions were determined in one chromosome pair in the complements of M. infesta, M. macrocarpa, M. italica (subgenus Micromeliotus), and M. alba and M. officinalis (subgenus Meliotus). The karyotypes of M. infesta and M. macrocarpa were found to be similar. Chromosomes of M. italica were larger than the chromosomes of the other four Melilotus species. The chromosome size in M. italica suggests the presence of large chromosomes in an ancestral or pro-Melilotus prototype. The chromosomes with satellites of M. infesta and M. macrocarpa appear to differ in morphology from the satellite chromosomes of M. …

Notes: Differences Among Nematode Populations In Tall Fescue Pastures In North, Central, And South Alabama, Jeffrey F. Pedersen, R. Rodriguez-Kabana

Department of Agronomy and Horticulture: Faculty Publications

Surveys of nematode populations in tall fescue (Festuca arundinacea Schreb.) pastures in north, central, and south Alabama in 1982 and 1983 showed significant differences in frequency of occurrence of many nematode species by geographical region. Although nematode damage has been implicated in the poor adaptation of tall fescue to the sandy soils of the extreme Southeast, many plant parasitic nematode species occurred in low frequency in south Alabama pastures. There were significant differences in the frequency of occurrence of Paratrichodorus christiei (Allen) Siddiqi by region. This nematode occurred with relatively high frequency in south Alabama in both years. There were …