bluuebunny/crossref_metadata_2025_split huggingface dataset:
Germination and Initial Growth of Kentucky Bluegrass in Soluble Salts1
Authors: Horst G. L. , Taylor R. M. 
Published: July 2010

AbstractKentucky bluegrass (Poa pratensis L.) has recently been considered for use as turf in high altitude regions of the arid Southwest where saline soils and saline irrigation water are a common problem. A laboratory experiment was conducted using saline hydroponic solutions with seeds of the bluegrass cultivars germinating and growing on floating mats. Solutions made from tap water consisted of 7500, 12 500, and 15 000 ppm NaCl and CaCl2 by weight, on an equal basis. Total germination, days to initial germination, leaf blade length, and blade fresh weight were measured. The objectives of this study were to determine the relative interspecific salt tolerances during germination and seedling growth of 44 bluegrass cultivars. Cultivars had highly significant germination and germination rate responses to salt stress. Seedling growth responses as measured by blade length and blade fresh weight were also significant. We found that a hydroponic growth medium containing 7500 ppm NaCl and CaCl2 salt would be suitable for identifying cultivars that have potential commercial value for saline growing conditions. At this salinity level, cultivars which average less than a 50% reduction in growth parameters relative to top yielding cultivars should be considered. A hydroponic medium with a salt concentration of 12 500 ppm would provide a suitable stress level for screening bluegrass genotypes for improved salt tolerance.Broad‐sense heritability estimates indicate that blade length, germination percentage, and germination rate would be valuable selection criteria for use in screening Kentucky bluegrass cultivars for salt tolerance. Apomictic reproduction may limit genetic improvement from recurrent selection.
Osmoconditioning of Beet Seeds to Improve Emergence and Yield in Cold Soil1
Authors: Khan Anwar A. , Peck Nathan H. , Taylor Alan G. , Samimy Cyrus 
Published: July 2010

AbstractTable beet (Beta vulgaris L.) seeds are characteristically slow germinating, and have a large time spread of germination. These characteristics interfere with the early establishment of a uniform, vigorous stand of seedlings in cold wet soil. This study was undertaken to determine if osmoconditioning (OC) of table beet seeds in polyethylene glycol 6000 (PEG) and MgSO4 solutions and/or other measures would improve germination and/or reduce germination time and thereby improve emergence, seedling establishment and yield. Seed balls of ‘Ruby Queen’ and ‘Cardenal’ were osmoconditioned in −1.2 and −1.18 MPa solutions of PEG and MgSO4, respectively. Treatments were performed at 15 °C for 7 days in the light. The benefits of OC were not lost by drying back the seeds. Aeration during OC followed by a 2 min rinse with water was the most effective treatment in improving germination or emergence in laboratory and growth chamber studies. In the 1980 field trial, OC in PEG improved the rate of emergence by 2 to 3 days, the stand by 40% and the root, top, and total yield by 40, 66, and 59%, respectively. In 1982, seedling emergence was biphasic. The first phase lasted 23 days and showed large differences in rate of emergence and stand between osmotically treated and untreated seeds and resembled the 1980 emergence pattern. The second phase commenced after a 30 mm rain with a resurgence of emergence in all treatments. The resurgence rate was highest in untreated seeds and this reduced the treatment differences in stand and yield. The resurgence was attributed to invigoration of the non‐germinated seed by low soil water potential (drought). Several MgSO4‐OC treatments increased the number of roots but decreased root size.
Turfgrass Evapotranspiration. I. Factors Influencing Rate in Urban Environments1
Authors: Feldhake C. M. , Danielson R. E. , Butler J. D. 
Published: July 2010

AbstractEvapotranspiration (ET) by turfgrass in urban environments is site specific and can vary considerably from what would be predicted from regional climate. A large degree of heterogeniety exists in residential microclimate and lawn management practices. The relative importance of these factors needs evaluation to aid in planning for efficient use of municipal water, half of which is applied to lawns in some western areas. This study, using small lysimeters, evaluated the relative effects of mowing height, N fertility, shading, grass species, and soil composition on ET. Kentucky bluegrass (Poa pratensis L. var. ‘Merion’) mowed 5 cm used 15% more water than grass mowed at 2 cm. Thirteen percent more water was used when 4 kg/1000m2 of N was applied each month during spring and summer compared to only one application for the season, applied in the spring. Evapotranspiration by grass in 1979 was essentially the same whether growing on a clay soil or on a sand‐peat mixture; however, a 6% decrease occurred for the soil system in 1980. Evapotranspiration increased linearly with solar radiation when an advective component of energy, accounting for 35% of ET, was subtracted from all solar treatments. Kentucky bluegrass and tall fescue (Festuca arundinacea Schreb. var. ‘Rebel’) which are cool‐season grasses, used over 20% more water than bermudagrass (Cynodon dactylon L. X Cynodon transvaalensis Davy var. ‘Tifway’) and buffalograss (Buchloe dactyloides Nutt) which are warm‐season grasses.
Fall Armyworm Resistance in Corn and Its Supression of Larval Survival and Growth1
Authors: Williams W. Paul , Davis Frank M. , Wiseman Billy R. 
Published: July 2010

AbstractThe fall armyworm [Spodoptera frugiperda (J. E. Smith)] is a serious pest of late planted corn (Zea mays L.) in the South; however, corn genotypes which show reduced leaf feeding damage have been developed. To study the effects of corn genotypes with and without resistance to leaf feeding by the fall armyworm on larvae development, field tests were conducted at Mississippi State, Miss. and Tifton, Ga. in 1980 and 1981. Experiments at Tifton were grown on a Tifton loamy sand (fine‐loamy, siliceous, Thermic, Plinthic Paleudult), and the experiments at Mississippi State were grown on a Leeper silty clay loam (fine, montmorillonitic, nonacid, thermic, Vertic Haplaquepts). Standard corn production practices were followed although soil insecticides were not applied. Fall armyworm larvae were placed in the whorls of susceptible and resistant corn genotypes at the 5 and 10‐leaf stages of growth. Fewer larvae were recovered from the resistant than the susceptible genotypes 8 days after infestation. Larvae produced on the resistant corn genotypes were also smaller than those produced on susceptible genotypes. Both number of surviving larvae and larval weights were highly correlated with leaf feeding ratings. Selections for reduced larval survival and growth, as well as reduced leaf feeding damage, should enhance efforts to develop corn genotypes with higher levels of resistance to fall armyworm.
A Plot Planting System Utilizing a Rear‐Engine Tractor1
Authors: Oplinger E. S. , Wright J. P. , Klassy A. 
Published: July 2010

AbstractTo meet the demands of several cultivar evaluation projects, a plot planting system utilizing a rear‐engine tractor was developed. Important design criteria were that it be adaptable to several different row spacings and row numbers, that it use only one seed packet per plot, and that it be easily transported. The equipment developed uses a 20 kw rear‐engine power unit equipped with a three point bitch behind the front axle. Seed is metered through a cone to a spinning divider which can be fitted with interchangeable heads to divide the seed into two to nine rows. Interchangeable tool bars, one equipped with double disc drill openers, the other with unit‐planters permit planting, as many as, nine 18‐cm rows, or as few as, two 95‐cm rows. The planting system has been used successfully for several crop evaluation trials, population and row width studies.
Copper Status of United States Soils and Forage Plants
Authors: Kubota Joe 
Published: July 2010

AbstractPlants with few exceptions are the primary sources of dietary Cu of grazing animals. Levels of Cu in plants are important to ruminant animals because the utilization of Cu is tied closely to that of Mo. Copper concentrations in forage plants grown on a wide range of U.S. soils were determined, and a summary is presented in this report. A geographic pattern of Cu concentration across the USA is illustrated in map form, using legumes as the test crop, and Cu levels of 6 mg kg−1 or less, 6 to 10 mg kg−1, and 10 to 12 + mg kg−1. The Cu concentrations in grasses were low, so their Cu concentrations were summarized separately from those of the legumes. The Cu concentration in neither the legumes nor the grasses, however, strongly reflected the Cu status (total) of soils. Compared with the geographic distribution pattern of Mo in U.S. forage plants, the pattern of Cu was quite diffuse due mainly to the narrow range of Cu in plants. An understanding of plant sources of Cu is important because ruminant animals grazed in parts of the USA suffer from molybdenosis, a Mo induced Cu deficiency disease. Animals afflicted with molybosis require supplemental Cu in addition to Cu from plant sources.
Root System Characteristics of Two Soybean Isolines Undergoing Water Stress Conditions1
Authors: Garay A. F. , Wilhelm W. W. 
Published: July 2010

AbstractEnvironmental stress may have a differential influence on root development of soybean [Glycine max (L.) Merr.] isolines which vary in pubescence density. Root length density and root dry matter distribution as a function of depth and distance from the row were determined for two isolines of ‘Harosoy’ soybean in association with an experiment designed to evaluate the influence of epidermal pubescence on root development, water use, and photosynthetic characteristics of the two isolines. The isolines, Harosoy normal (HN) and Harosoy dense (HD), differed in the density of trichomes on the epidermal surfaces of leaves, stems, and pods. The study was conducted at the Univ. of Nebraska Field Laboratory at Mead, Nebr., during the 1980 growing season. Root samples were collected 47 (full bloom) and 78 (beginning seed) days after planting. Until the first sampling, soil water content was high at all depths, and roots were concentrated in the surface 0.15‐m layer, especially under the row. Eighty percent of the roots were found within the upper 0.30 m. By 78 days after planting and after 30 days of drought, root length density was greatest at the 0.90 to 1.20‐m layer; 80% of the roots were found within the 0 to 1.2‐m layer; and uniform lateral distribution was observed. Harosoy dense pubescence isoline tended to have a greater root density, to explore deeper into the soil, and to extract more soil water during the drought than did the normal pubescence isoline. However, the rate of water extraction (per unit root length) was greater for the HN isoline.
Relation of Agronomic and Multispectral Reflectance Characteristics of Spring Wheat Canopies1
Authors: Ahlrichs J. S. , Bauer M. E. 
Published: July 2010

AbstractRemote sensing technology is nearing operational use for area estimation of wheat (Triticum aestivum L.). However, the relationships between crop canopy variables such as leaf area index (LAI) which might be used in large‐scale applications of growth and yield models of wheat and other crops and their multispectral reflectance properties are not well defined. The objective of this investigation was to identify these relationships and assess the potential for estimating selected canopy variables from remotely sensed reflectance measurements. Reflectance spectra over the 0.4 to 2.5 µm wavelength range were acquired during each of the major development stages of spring wheat canopies at Williston, N.D., during the 1975, 1976, and 1977 seasons. The soil was a Williams loam (fine‐loamy mixed typic Argiboroll). Treatments in the experiment included planting date, N fertilization, cultivar, and soil moisture. Agronomic characterization of the canopies included measurements of development stage, plant height, fresh and dry biomass, LAI, and percent soil cover. Correlation and regression analyses were used to relate the agronomic variables to reflectance factor. High correlations were found between reflectance factor and percent soil cover, LAI, biomass, and plant water content. A near infrared wavelength band, 0.76 to 0.90 µm, was most important in explaining variation in green LAI and percent soil cover, while a middle infrared band, 2.08 to 2.35 µm, explained the most variation in fresh and dry biomass and plant water content. Transformations, including the near infrared/red reflectance ratio and greenness index, were also highly correlated with canopy variables. The relationship of canopy variables to reflectance was influenced by the development stage of the crop and decreased after anthesis. The canopy variables could be accurately predicted using measurements from three to five wavelength bands. The reflective wavelength bands of the thematic mapper sensor were more strongly related to and better predictors of the canopy variables than the Landsat MSS bands.
Fruiting of Cotton. II. Effects of Plant Moisture Status and Active Boll Load on Boll Retention1
Authors: Guinn G. , Mauney J. R. 
Published: July 2010

abstractYield of cotton (Gossypium hirsutum L.) is proportional to the number of fruits (bolls) produced, which is a function of flower production and boll retention. It bas been known for many years that a severe water deficit decreases boll retention, but tbe reports did not indicate a critical plant water status below which field‐grown plants lost bolls. Field experiments were conducted with 'DPL 70' cotton on an Avondale clay loam (a member of the fine‐loamy, mixed, hyperthermic family of Typic Torrifluvents) to a) quantify the relationship between leaf water potential (xylem pressure potential) and boll retention, and b) to assess the importance of boll load in modifying the results. Two irrigation levels were compared through the season. Boll retention was high early in the season at midday leaf water potentials from −1.4 to −1.9 MPa, but decreased when the leaf water potential decreased below about −1.9 MPa. Boll retention decreased as boll load increased. Because water deficit decreased flowering and boll retention, it limited the boll load. The feedback effect of boll load on boll retention tended to counteract the effect of water deficit on boll retention. Water deficit decreased yield, in part because of decreased flowering and in part because of decreased boll retentio
Leaf Gas Exchange in ‘Caucasian’ Bluestem in Relation to Light, Temperature, Humidity, and CO21
Authors: Coyne Patrick I. , Bradford James A. 
Published: July 2010

abstractLeaf gas exchange was measured in glasshouse‐grown Old World bluestem [Bothriochloa caucasica(Trin.) C. E. Hubb cv. Caucasian] as a function of light, temperature, humidity, and CO2to provide a database for developing a model to aid in deriving specific genotypeenvironment combinations that result in optimum forage production. The CO2resistance pathway was partitioned into stomatal (r′sand residual (r′r) components and a water‐use efficiency index (r′s/r′twhere r′2= r′s+r′t) was calculated. Maximum CO2exchange rates (CER) were 40 µmol m−2s−1which are above the average of published rates of numerous C4 perennial grasses. Maximum r′s/r′twas about 70% of the theoretical potential and was markedly superior to comparable values from the literature. The r′s/r′tratio declined rapidly as temperature was decreased or increased from the optimum for maximum CER (36 °C) due to the greater temperature sensitivity of r′gcompared to r′s. The ratio of r′s/r′rwas greater than unity for temperatures greater than 20 °C and photon flux densities greater than about 150 µmol m−2s−1and maximum r′srrat high light and Toptwas about 2.5. Increasing the leaf‐air vapor pressure difference (VPD) resulted in linear reductions in CER and stomatal conductance (Ca). The decrease in CER per unit reduction in Ca(ratio of regression slopes) resulting from the imposition of atmospheric water stress increased from 2.3 at 15 °C to 4.2 at 35 °C showing increased stomatal control of CO2uptake as temperature was increased. Stomatal behavior may vary with growing conditions, but in this experiment, stomates did not operate to maintain internal CO2constant independent of ambient CO2and light. Caucasian bluestem's high CER and r′srtare consistent with its demonstrated forage production potential. Together, these attributes suggest a promising role for the Old World bluestems (Bothriochlocr spp.) on marginal cropland sites in the Southern Plains to complement and supplement native range.
Rapidly Determining Sorghum Canopy Photosynthetic Rates with a Mobile Field Chamber1
Authors: Garrity Dennis P. , Sullivan Charles Y. , Watts Darrell G. 
Published: July 2010

AbstractProgress in characterizing the photosynthesis of plant communities under field conditions demands simple, rapid methods for determining CO2exchange rates in the field. With conventional flow‐through gas exchange systems, difficulties are faced because of the need for an electrical power source to operate the analyzer in the field and the lack of mobility of this multiple component system. Recently, a technique was developed for precisely measuring CO2concentrations of small gas samples collected in medical syringes. We describe the design and operation of an assimilation chamber that adapts this technique into a rapid and mobile method for canopy photosynthesis measurements on grain sorghum [Sorghum bicolor(L.) Moench). The chamber and all accessories can be hand‐carried by two people. Two to 3 min are required to sample the photosynthetic rate of a 0.86 m length of crop row at any given location. The chamber is constructed of acrylic plastic with aluminum reinforced corners. A unique ventilation system was designed using an exhaust blower powered by a lightweight 12 v battery. The differential in CO2concentration between air samples drawn at 0 and 60 s provided the basis for canopy apparent photosynthesis determinations. Diurnal measurements of the canopy photosynthesis of sorghum under different soil moisture regimes on two dates are reported. The convenience and mobility features of the method suggest numerous applications in field investigations where conventional CO2exchange systems are impractical.
Physiological Response of St. Augustinegrass to Irrigation Scheduling
Authors: Peacock C. H. , Dudeck A. E. 
Published: July 2010

AbstractIrrigation is an integral part of a turfgrass management program and accounts for a large part of the energy inputs on a turf area. As potable water supplies decrease, use of limited water will impose stress on turfgrass areas which may result in reduced quality. Research on irrigation practices should help to minimize the effects of water stress resulting from reduced irrigation frequency. Response of St. Augustinegrass [Stenotaphrum secundatum(Walt.) Kuntze] to irrigation scheduling was studied during the summers of 1980 and 1981 on a loamy, siliceous, hyperthermic Grossarenic Palendult soil. An irrigation schedule of 2‐, 3‐, 4‐, and 6‐day intervals simulated conditions ranging from grass being under no water stress to severe water stress. Field plots were constructed to maintain an undisturbed soil profile that horizontally isolated adjacent plots to prevent lateral water movement. Irrigation treatments were implemented by irrigating with evapotranspiration estimates of 0.64 cm day−1in 1980 and 0.38 cm day−1in 1981 at either 2‐,3‐,4‐, or 6‐day intervals. Plots received equal volumes of water, only irrigation timing was varied. Turfgrass swards were evaluated on 12‐day cycles under water stress prior to irrigation and after 24 h of recovery following irrigation. Measured parameters included turfgrass quality, carbon exchange rates (CER), evapotranspiration rates (ET), plant water potential component changes, and leaf diffusive resistance, and transpiration. Irrigation scheduling affected many of the parameters studied. The 6‐day irrigation schedule caused a reduction in CER and ET and concurrent increase in stomatal resistance and a loss of turgor pressure prior to irrigation. Following irrigation, CER and ET increased, turgor pressure increased, and diffusive resistance decreased during each 12‐day cycle. When averaged over the entire study period preirrigation values of CER, ET, leaf water potential components, and transpiration were lowest and diffusive resistance highest for the 6‐day schedule, and these increased or decreased during recovery following irrigation. Even under the most severe conditions of 0.38 cm of water day−1applied every 6 days, the sward remained in positive carbon balance. Turfgrass quality and percent cover were not affected by irrigation treatments. Scheduling irrigation every 6 days with 2.3 cm of water will not affect St. Augustinegrass turf quality if adequate mowing height is maintained.
Adventitious Rooting in ‘Hopi’ Sunflower: Function and Anatomy1
Authors: Rogers C. E. , Unger P. W. , Kreitner G. L. 
Published: July 2010

AbstractThe ‘Hopi’ sunflower (Helianthus annuusL.) is a primitive openpollinated variety that produces numerous adventitious buds (nodules) on exposed lower stalks under greenhouse conditions. Similar conditions do not induce such budding in more advanced hybrids. The root buds remain dormant when exposed to air, but begin rapid growth into adventitious roots when covered with damp soil. Objectives of this study were to determine the effects of adding basal soil around stalks of Hopi and hybrid ‘894’ sunflower on adventitious root development, contribution of the roots to plant standability, and anatomy of the roots. The addition of one or two 100‐mm layers of soil around lower stalks induced significantly more (1% level) adventitious root growth above the original soil level on stalks of Hopi variety than on hybrid 894 stalks. When the addition of soil was delayed until plants were flowering, extensive adventitious rooting still occurred in Hopi sunflower, but little occurred in hybrid 894. Applying horizontal forces to stalks 0.3 and 0.6 m above the original soil level caused significantly less stalk deflection in Hopi than in hybrid 894 plants. The greater resistance to stalk deflection in Hopi was attributed to greater plant stability furnished by more extensive adventitious rooting. Anatomical studies revealed that the internal anatomy of adventitious roots was nearly identical to the internal anatomy of primary roots for both Hopi and hybrid 894. Roots of hybrid 894 had larger intercellular spaces in the cortex and a higher xylem to cortex ratio than comparable roots of the Hopi variety.