bluuebunny/crossref_metadata_2025 huggingface dataset:
Drying Rate and Ruminal Nutrient Digestion of Chemically Treated Alfalfa Hay1
Authors: Nocek James E. , Fallon Janet B. , Fessenden Marianne R.
Published: July 2010

The effect of chemical drying agents (DA) in combination with surfactant (S) applied to first‐cutting alfalfa (Medicago sativa L.) hay has been variable in reducing drying time. Furthermore, their effect on nutrient availability in rumen has not been ascertained. The objectives of this study were to evaluate the effect of DA concentration and S addition, when applied at mowing, on drying rate, ruminal nutrient availability, and digestion rate of first‐cutting alfalfa hay. Treatments included: UC = untreated control; Lo‐DA/S = DA applied at 30 g L−1 with additional S; Lo‐DA = 30 g L−1, no S; Hi‐DA/S = 60 g L−1, with additional S; and Hi‐DA = 60 g L−1, no S. The trial was conducted in the field, utilizing four replications of each treatment to evaluate drying rate. Two ruminally cannulated cows (Bos indicus) were used to measure the influence of DA on in situ dry matter (DM), nitrogen (N), neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility. All treated alfalfa had faster drying rates than UC. Drying agent concentration or S addition had no effect on drying rate. Drying agents did not influence relative proportions of soluble, ruminally digestible or indigestible DM. However, undigestible N, NDF, and ADF increased compared to UC. Rate of ruminal ADF digestion was decreased by DA application. Additional S increased the proportion of indigestible DM, N, and NDF regardless of DA concentration. Digestion rates for N increased for Lo‐DA/S and Hi‐DA compared to Lo‐DA and Hi‐DA/S. Digestion rates for NDF increased and ADF decreased by S addition, Hi‐DA treatments having higher NDF and ADF digestion rates than Lo‐DA treatments. Drying rate of alfalfa hay was increased by chemical treatment at mowing. However, chemical treatment had a variable effect on ruminal nutrient availability.
Somatic Analysis of a Mutable Trait for Anthocyanin Pigmentation in Alfalfa1
Authors: Talbert L. E. , Bingham E. T.
Published: July 2010

Mutable anthocyanin pigmentation in alfalfa (Medicago sativa L., 2n=4x=32) is characterized by streaks and sectors of pigment in flower petals and seeds that are otherwise white. Similarly, hypocotyls and stems of mutable plants have streaks and sectors of pigment. The mutable condition was discovered in a plant in the F2 generation of a cross between ‘Ranger’ and a white‐flowered stock. In the present study, 21 mutable plants descending from the original mutable plant were examined over several cycles of regrowth in the field and greenhouse for 2 yr. All 21 mutable plants eventually produced a branch or a shoot with entirely purple flowers. Two of the 21 mutable plants produced shoots with fewer streaks per petal than the main plant, and one of the 21 plants produced a shoot with white flowers. Clonal lines of shoots with changes in the mutable condition were propagated by shoot cuttings. In one case all variations in mutable frequency as well as white flowers were propagated by cuttings from one plant. Self‐progeny of purple‐, mutable‐, and white‐flowered propagules of this plant segregated for similar frequencies of purple‐, mutable‐, and white‐flowered plants. This result indicated that the germline was the same among propagules and that changes in flower pigmentation were periclinal chimeras. Histological examination revealed that pigmentation is in the epidermal cell layer of the flower petals and in the outermost subepidermal layer of hypocotyls and stems. Mutation to the dominant state commonly occurs relatively late in development of petals, seed coats, and stem tissue, and results in streaks of pigment. Mutation to the dominant state earlier in development occurs at a much lower frequency and results in purple flowered shoots that usually are periclinal chimeras. Mutation to the dominant state in the germline results in purple‐flowered progeny that segregate along with mutable‐ and white‐flowered progeny in self and testcross families. Allelism tests indicated that the mutable trait is attributable to a mutable allele at the C2 locus. The allele frequently mutates from the recessive to the dominant state of C2. Mutable‐flowered progeny inherit the allele in its mutable state. The mutable state may be caused by the interaction of a transposable element with a dominant allele at the C2 locus.
Genetic Linkage between Glume Color and Certain Gliadin Proteins in Durum Wheat1
Authors: Hare R. A. , du Cros D. L. , Barnes W. C.
Published: July 2010

The genetic linkage between glume color and certain gliadin proteins in the endosperm of durum wheat (Triticum turgidum L. group durum) was determined by classifying F3 families from two crosses in which ‘Kamilaroi’ sibs were crossed to homozygous lines derived from ‘Anhinga’ selection/‘Leeds’ and ‘Wells’/56111. Particular attention was focused on linkage between the locus controlling gliadin group 42 and group 45 with that conditioning glume color, Rg 1. An estimate of the recombination value was calculated to be 5.4%. The group 45 gliadin proteins are presumed to contribute to gluten strength, while group 42 proteins are associated with gluten weakness. The close linkage between these gliadin proteins and glume color will permit selection for gluten strength in early generations of a durum wheat breeding program.
Evidence for Different Genes Controlling Insect Resistance in Three Soybean Genotypes1
Authors: Kilen T. C. , Lambert Lavone
Published: July 2010

Soybean [Glycine max (L.) Merr.] introductions PI 171451 (‘Kosamame’), PI 227687 (‘Miyako White’), and PI 229358 (‘Sodendaizu’) have been reported to be resistant to several insect species. Although these foreign cultivars have been used in breeding programs to develop enhanced germplasm having resistance to foliar feeding insects, it is unknown if resistance is controlled by identical genes. The objective of this study was to determine if the same or different genes control resistance in the three sources. Parents and F3 lines from crosses among the resistant cultivars were rated visually for leaf feeding damage by velvetbean, caterpillar (Anticarsia gemmatalis Hübner) in a greenhouse and a field cage. A highly consistent pattern of very susceptible F3 lines recovered from crosses between resistant parents suggests that each carries at least one gene for resistance that is different from the other sources. This finding suggests a potential for developing gene pools from which selection of higher levels of resistance might be made.
Glycine Series as a Model to Study near Infrared Reflectance Spectra1
Authors: Coblentz W. K. , Shenk J. S. , Gustine D. L.
Published: July 2010

Near infrared reflectance (NIR) spectra supply the basic information utilized to relate vibrational information of functional groups to the quality analysis of forages and feedstuffs. The spectra are used to quantify the mathematical relationship between functional group information and the chemical analyses currently in use. This paper was developed using the amino acid glycine and its di‐, tri‐, and tetrapeptide forms to demonstrate that the information due to various chemical functional groups appearing in the mid‐infrared region could be located and identified in the NIR region. Spectra for the glycine series were obtained on a spectro‐computer system. Absorption peak assignment was conducted using mathematical calculations and direct comparison with published spectra. The region from 1000 to 1900 nm was found to be an overtone region and 1900 to 2600 nm a combination region. Three regions of the spectra contained primarily carbon information. They were 1000 to 1460,1600 to 1900, and 2240 to 2600 nm. The N regions were 1460 to 1590 and 1900 to 2230 nm. These findings verify that the fundamental information originating in the mid‐infrared (IR) region is contained in the NIR region in a complicated form as overtones and combinations of the primary IR absorption. A better understanding of these principals will be useful in future quantitative research with forage and feed.
Nitrogen Use in a Seedling Synthetic Allohexaploid Developed from Durum Wheat and Aegilops Squarrosa1
Authors: Henson James F. , Gronwald John W. , Leonard Robert T. , Waines Giles J.
Published: July 2010

A seedling synthetic allohexaploid of durum wheat (Triticum turgidum L. var. durum Desf. ‘Produra’) and Aegilops squarrosa L. was compared with its parents for root NO−3 uptake rate in solution culture 21 to 28 days after germination. The allohexaploid, its parents, and a bread wheat (T. aesticum L., ‘Anza’) were compared for N accumulation and cumulative NO−3 reduction in sand culture 30 days after germination. The NO−3 uptake rate of Ae. squarrosa was greater than that of Produra in solution culture, and that of the allohexaploid was intermediate. In sand culture, the allohexaploid was not different from Produra for either N accumulation or cumulative NO−3 reduction, even though Produra and Ae. squarrosa differed for these characters. The allohexaploid and Anza did not differ for N accumulation. Anza had higher cumulative NO−3 reduction in roots, but not in shoots, than the allohexaploid.
Low Ribonuclease I Activity Prior to Cold Acclimation in Freeze Selected Winter Barley1
Authors: Kenefick D. G. , Blake T. K.
Published: July 2010

Etiolated 4‐day‐old shoot tissue of freeze‐resistant winter barley (Hordeum vulgare L.) contains low ribonuclease I (EC 3.1.27.5) activity compared to susceptible cultivars, an indigenous distinction found in nonacclimated tissue. The objective of this report was to determine if a shift in plant population caused by freeze selection resulted in changes in ribonuclease activity of leaf tissue. The RNA‐degrading activity in tissue extracts was determined spectrophotometrically and by assays using disc polyacrylamide gel electrophoresis (PAGE) of tissue extracts. Increased freeze survival in hybrid lines and reduction of RNA‐degrading activity were demonstrated by subjecting F5 plants to freeze selection. Extracts from tissue of the freeze‐susceptible (‘Tennessee Winter’) cultivar contained higher total activity than was present in extracts from the freeze‐resistant (‘Dicktoo’) cultivar for range of tissue ages. The prominent distinction between the cultivars in 20‐day leaf tissue was a slowly migrating ribonuclease band found at the midpoint of gels containing extracts of the susceptible cultivar, which was essentially absent in the resistant cultivar. A consequence of selection for freeze resistance in winter barley was a reduction in variation of enzyme activity among plants within a cultivar and a lowering of activity. These data were consistent with results showing a selective shift from high to lower activity in composite extracts of shoot tissue grown from seed of unselected and freeze selected plants, respectively.
White Clover Seed Germination in Agar Containing Tall Fescue Leaf Extracts1
Authors: Pederson G. A.
Published: July 2010

Studies of allelopathic effects on germination have commonly used filter paper moistened with plant extracts as a germination medium. In our laboratory, this method gave inconsistent results due to nonuniform wetting or localized swelling of the paper. The objective of this study was to develop a method using agar as the germination medium to test ‘Star’ and ‘Tillman’ white clover (Trifolium repens L.) for germination and growth in tall fescue (Festuca arundinacea Schreb.) leaf extracts containing 0, 100, 200, and 300 g leaves L−1 water. White clover root length score decreased from 3.55 to 2.01 (on a 1 to 5 scale) with increasing rates of tall fescue leaf extract in agar. No consistent relationship between extract rate and root length was observed using germination paper. Coefficients of variation for root length of Star and Tillman were 6.8 and 5.6 on agar and 21.9 and 15.8 on germination paper. The extract agar method should be useful in studies of allelopathic effects on germination and initial growth of other plant species.
Screening Sericea Lespedeza for Aluminum Tolerance1
Authors: Joost R. E. , Hoveland C. S. , Donnelly E. D. , Fales S. L.
Published: July 2010

A procedure was developed to screen sericea lespedeza [Lespedeza cuneata (Dumont) G. Don.] germplasm for AI tolerance. Sericea seeds were germinated and maintained for 7 days in petri dishes containing either distilled water or 0.5 mM AI at pH 4.5. Aluminum tolerance, evaluated as relative radicle length (RRL), ranged from 0.26 for the sensitive ‘Interstate 76’ to 0.58 for the most tolerant sericea entry. Results from the screening procedure were correlated with relative root and herbage yields (r= 0.89*, significant at the 0.05 probability level, and 0.82*, respectively) from a field study conducted at pH 4.7 and 6.0 on an acid Altavista loamy sand (fine‐loamy, mixed, thermic Aquic Hapludults). All the sericea entries evaluated were superior to alfalfa (Medicago sativa L.) in AI tolerance. Comparison of forage quality data with the AI tolerance ratings indicated that selection for improved quality in sericea had no effect on AI tolerance.
Inheritance of Phytophthora Root Rot Resistance in Two Diploid Alfalfa Species1
Authors: Havey M. J. , Maxwell D. P.
Published: July 2010

Phytophthora root rot [caused by Phytophthora megasperma Drechs. f. sp. medicaginis (Pmm)] is a major cause of decline of alfalfa (Medicago sativa L.) grown in poorly drained soils. Diploid (2n = 2x= 16) Medicago species have been described as sources of resistance to diseases of cultivated tetraploid (2n=4x=32) alfalfa and are a potential source of resistance to Pmm. The objective of this project was to study the inheritance of resistance to Pmm in plant introductions of diploid M. falcata L. (PI 410970) and M. sativa subsp, × varia (Martyn) Arcangeli (PI 325408). Plants were grown in the greenhouse in pots containing a peat‐sand mix (1:1, v/v) and inoculated at 8 weeks with a chopped mycelial suspension of Pmm. Plants resistant and susceptible to Pmm were retained from both diploid Medicago species for use in inheritance studies. Segregations of 3:1 (resistance:susceptibility) in F1 families and backcrosses to the susceptible parent indicated that resistance to Pmm in M. falcata was conditioned by a dominant allele at either of two independently segregating loci, designated as Pm3 and Pm4. Resistance to Pmm in M. sativa subsp, × varia was heritable, but no mode of inheritance is proposed because unexplained segregation ratios were observed in the backcross to the resistant parent. These results demonstrate that M. falcata is a source of a simply inherited resistance to Pmm.
Effect of Hot Water Treatments on the Quality of Rice Seed Destined for International Exchange1
Authors: Ventura Alicia Rocha , Garrity Dennis P.
Published: July 2010

Hot water treatment is used to control seedborne pathogens of rice (Oryza sativa L.) but it may adversely affect germination and seedling vigor. If cnltivars differ in sensitivity to the hot water treatment used, performance in international cultivar trials may be confounded by the differential hot water effect. We tested alternative hot water treatments within the recommended range for plant quarantine to determine their effects on the viability, vigor, and longevity of seeds of four rice cultivars differing in thermal sensitivity. Factors tested included water temperature, length of immersion period, effect of presoaking the seed, and storage conditions after treatment. Hot water treatment at 52°C for 15 rain was physiologically safe for rice seed regardless of cultivar, storage condition after treatment, or whether presoaking was practiced before the treatment. The 52°C/15‐min treatment actually increased field seedling vigor and tiller number over the untreated control. The 52°C/30‐min treatment had significant deleterious effects on the germinability of two out of four cultivars after 45 days in storage. The 57°C/15‐min treatment produced deleterious effects when the seeds were presoaked and stored under tropical room conditions (25 to 32°C/78% relative humidity). The 57°C/30‐min treatment consistently decreased seed quality in all tests and is considered an unsafe treatment for rice seed. Temperaure, exposure period, presoaking period, storage conditions, and length of storage interacted synergistically in their deleterious effects on rice seed. Safe treatments were defined in terms of all of these factors. Cultivaresponses to the various hot water treatment combinations were generally similar. The most sensitive cultivar was japonica ‘Nan Keng 32’.
Cultivar Differences in Nitrogen Remobilization during Grain Fill in Soft Red Winter Wheat1
Authors: Van Sanford D. A. , MacKown C. T.
Published: July 2010

Remobilization of vegetative N during grain fill in wheat (Triticum aestivum L.) contributes significantly to final grain N content. To assess cnltivar variation for this trait in soft red winter (SRW) wheat, nine cultivars were evaluated in the field for 2 yr at one location on a Maury silt loam soil (fine, mixed, mesic, Typic Paleudalf). Plants were harvested at anthesis and maturity, and divided into spike, peduncle, flag leaf blade; and lower culm plus leaves. Significant cultivar differences in N remobilization from the tlag leaf blade, peduncle, and lower culm were detected. The proportion of N accumulated by the spike derived from vegetative N remobilization ranged among cuitivars from 51 to 91%. Approximately 83% of the total aboveground N at maturity was present in the plant at anthesis, in agreement with other studies. An analysis of cultivar differences indicated that all of the cultivar variation in final spike N could be associated with variation in total N uptake. Cuitivar differences in partitioning of vegetative N measured at anthesis did not contribute significantly to cultivar differences in final spike N. Postanthesis N uptake was associated with lower N utilization efficiency (spike weight/total plant N), higher grain N concentration, and lower grain yields. A controlled study with nutrient solutions subjected six wheat cuitivars to N deprivation at anthesis. The impact of N deprivation on grain N concentration varied among cultivars. The ratio of spike N to total N in all cultivars was increased by N deprivation from 0.69 in the presence of N to 0.82 in the absence of N. For the three cultivars common to both studies, field performance did not agree well with performance under controlled conditions.
Amelioration of Chilling Injury in Rice Seedlings by Mefluidide1
Authors: Zhang L. X. , Li P. H. , Tseng M. J.
Published: July 2010

Rice (Oryza sativa L.) seedlings at two to three leaf stage were used for testing mefluidide (/V‐[2,4‐dimethyl‐5‐[[(trifluoromethyl)‐ sulfonyl)amino]phenyl]acetamide) protection of chilled plants. After 8‐days exposure to 6°C, seedlings sprayed with 3, 5,10, and 15 mg mefluidide L−1 had 29,30,29, and 31% injury, respectively. Controls showed > 65% damage. During the 8‐day chilling period, consistent levels of about 30% electrolyte leakage were observed among the mefluidide‐treated plants, whereas controls showed an increase in leakage from 30 to 70%. It appears that mefluidide may alter plasma membrane properties and thus lead to increased tolerance to chilling stress. Significant protection was apparent 6 h after mefluidide treatment. Protection can last for at least 72 h after treatment. Chilled, mefluidide‐treated plants grew taller and flowered 5 to 10 days earlier than chilled controls. Although high concentrations of mefluidide can stunt plant growth, at concentrations of 5 to 10 mg L−1 rice plants did not exhibit any adverse growth and development characteristics. A 5 mg mefluidide L−1 application appeared to stimulate plant growth in a nonstressed environment.
Influence of Prestress Environment on Annual Bluegrass Heat Tolerance1
Authors: Martin D. L. , Wehner D. J.
Published: July 2010

Annual bluegrass (Poa annua L.) turf quality is reduced during periods of high temperature. To predict heat stress injury and develop improved prestress maintenance practices, an understanding of the seasonal variation in annual bluegrass heat tolerance and the influence of soil moisture on heat tolerance is crucial. Annual bluegrass growing in the field on a Drummer silty clay loam (fine silty, mixed, mesic Typic Haplaquolls) was sampled on 23 dates over two growing seasons and brought to a laboratory for exposure to high temperature. Prestress environmental conditions (air and soil temperature, soil matric potential, plant water potential, daylength, rainfall and irrigation) were monitored. Plants were enclosed in plastic bags, exposed for 30 min to temperatures in the range 40 to 48°C in a water bath and placed in a greenhouse for a 2‐week recovery period. The dry weight of the stressed plants expressed as a percentage of the controls (heat tolerance indices, HTI) was used as a measure of heat tolerance. In a second experiment, field plots of annual bluegrass were maintained for one growing season under either a dry (rainfall plus irrigation to prevent severe wilting) or moist (dry treatment plus 10‐mm irrigation every other day) soil regime. Plants were stress‐tested on five dates when differences in soil matric potentials existed between treatments, and on five dates when matric potentials were identical (saturated soil). Turfgrass color, quality, and rooting depth were monitored. The best equation fitted to HTI using the results of the first experiment was: y = 15.6 ✕ A + 9.85 ✕ B − 0.22 ✕ A2 − 0.31 ✕ B2 − 0.25 ✕ A ✕ B ✕ 194.71 (R2 = 0.78, p = 0.0001), where A = mean maximum daily air temperature (°C) for the 2 days preceding sampling and B = mean total precipitation (mm) of the period 2 through 4 days prior to sampling. The second experiment revealed a nonsignificant trend for annual bluegrass maintained under moist soil conditions to be less heat tolerant than that under dry conditions. No differences were found due to treatment in rooting depth which negatively correlated (r = −0.83) with the soil temperature at 10 cm. Because of reduced turfgrass quality with the dry soil conditions, there appeared to be little potential for increasing heat tolerance through irrigation management.
Prediction of Leaf Fraction, Neutral Detergent Fiber, and Intake of Ground Forage Samples by Airflow Segregation1
Authors: Rao Kanneganti V. , Van Soest P. J. , Fick G. W.
Published: July 2010

Research on forage nutritional quality is facilitated by procedures that are fast and simple and that require only small samples. This is especially true for dry matter intake, which can now be accurately evaluated only by feeding trials. In order to evaluate airflow segregation as a method of forage analysis, oven dried forage samples, ground to pass a 2‐mm screen, were separated into coarse and fine portions using several airflow speeds in a seed cleaner. An airflow speed setting of 7 units gave the cleanest separation of leaf from stem material, but contamination of the coarse portion with leaf fragments and of the fine portion with stem fragments could be easily seen at 4✕ magnification. However, for alfalfa (Medicago sativa L.), actual leaflet fraction of the original herbage regressed on coarse portion of the separated material gave the equation Y = 1.669 – 2.665. X, n = 25,r2 = 0.99, and a root error mean square of 0.024. Neutral detergent fiber (NDF) and intake of alfalfa herbage were highly correlated to the coarse portion (r = 0.85 and ‐0.87, respectively), but this was not true when other forage species were considered. Airflow separation can be calibrated to predict leaf and NDF fractions of pure alfalfa samples, but a universal relationship was not found across a range of temperate forages.
Soybean Mutants with Increased Tolerance for Sulfonylurea Herbicides1
Authors: Sebastian Scott A. , Chaleff Roy S.
Published: July 2010

Soybean [Glycine max (L.) Merr.] tolerance for residues of chlorsulfuron [2‐chloro‐N‐[(4‐methoxy‐6‐methyl‐l,3,5‐triazin‐2‐yl)amino]carbonyl]benzenesulfonamide] would permit use of this small grain herbicide in regions where small grains and soybean are grown in rotation. A soybean mutation breeding program was conducted to induce, select, and characterize mutations giving increased genetic tolerance for chlorsulfuron and related sulfonylurca (SU) herbicides. Following seed mutagenesis with ethylnitrosourea (ENU) and subsequent selection, four mutant soybean lines with increased chlorsulfuron tolerance were isolated. Tolerance was conditioned by a single recessive gene in all four mutants. Allelic studies indicate that each mutation resides at one of three loci. Mutant 1‐184A, which was studied most extensively, displayed more tolerance for preplant incorporated and postemergence levels of chlorsulfuron and a related sulfonylurea, chlorimuron ethyl [ethyl 2‐[[[[(4‐chloro‐6‐methoxypyrimidin 2‐yl)amino]carbonyl]amino]sulfonyl]benzoate], than did ‘Williams’. Biochemical studies indicate that the mutants do not contain an altered form of acetolactate synthase (the site of action of these sulfonylurea herbicides).
Genetic Studies of Crown Depth and Subcrown Intenode Length in Winter Wheat1
Authors: Poulos Jean M. , Allan R. E.
Published: July 2010

Crown depth (CD) and subcrown internode length (SIL) affect coldhardiness of winter wheat (Triticum aestivum L.). Information on their inheritance and comparative value as selection criteria is limited. This study measured the heritability and predicted selection gain for CD and SIL in crosses involving a common parent and three semidwarf cultivars differing for CD and SIL. The semidwarfs were ‘Daws’ (DA), ‘Nugaines’ (NU), and ‘Stephens’ (ST), which deep vs. short, intermediate vs. intermediate, and shallow vs. long CD and SIL phenotypes, respectively. The common non‐semidwarf parent was ‘Cappelle Desprez’ (CA), which has shallow CD and long SIL. A greenhouse procedure was devised and compared to field tests. The relationships of CD and SIL to seed depth (SD), coleoptile length (CL), and plant height were determined. In the greenhouse, progeny of most populations segregated for CL, SIL, and CD. In the field, all except the CA/ST progeny segregated for CD, but none segregated for SIL. Genotype by environment interactions were not significant (P > 0.05) for SIL and CD, except for CD of the CA/ NU population. Seed depth had a greater effect on SIL than on CD, and, accordingly, SIL had less utility as a selection criterion than CD. In the greenhouse, parent‐progeny heritability estimates ranged from 0.32 to 0.42 for CD and 0.29 to 0.48 for SIL. Heritability estimates ranged from 0.00 to 0.37 for CD and 0.03 to 0.24 for SIL, when F4 field data were regressed on F3 greenhouse data. Dominance or overdominance occurred for shallow CD and long SIL. Most segregating generations showed nearly continuous variation and trangressive segregation for CD and SIL. At a 10% selection intensity, the average expected gain from selection was 2.9 mm for CD and 3.3 mm for SIL.
Comparison of S1 and Modified Ear‐to‐Row Recurrent Selection in Four Maize Populations. I. Effects on Population Means and Variances1
Authors: Sullivan J. A. , Kannenberg L. W.
Published: July 2010

Concern for the narrow genetic base of modern maize (Zea mays L.) hybrids has resulted in an increased interest in a population approach to germplasm improvement and the most effective recurrent selection methods for the adaptation and improvement of such populations. Two widely used procedures for intrapopulation improvement in maize are S1 (S) and modified ear‐to‐row (ME) selection. The objective of this study was to compare the effectiveness of these two procedures in four open‐pollinated maize populations, Afton (A), Schindelmeiser (S), Gelber Badischer Landmais (G), and Northwestern Dent (N). The primary trait of selection was performance index (PI = grain yield/percent grain moisture). The effects of selection were assessed for PI, the components of PI: grain yield and percent ear moisture at harvest, and other agronomic traits. Genetic variance was estimated to determine possible relationship to observed progress from selection. Data are reported for the initial three cycles of each selection procedure. The S selection for PI resulted in significant average linear increases in PI of 13, 12, and 19% per cycle in A, G, and N, respectively. Increases in PI were a result of increases in grain yield and decreases in percent moisture at harvest. ME selection produced no significant changes in PI. Genetic variances were estimated by subtracting environmental variance (as estimated from single‐cross hybrids) from the phenotypic variance of each cycle. Significant reductions in genetic variances from Cycle 0 were detected for grain yield in (S)Cycle 3 of S, G, and N, and were numerically lower in all selected populations. Genetic variances for percent ear moisture declined significantly in only two instances, ^(ME)Cycle 3 and G(S)Cycle 3. This study indicated that S selection was the preferred method of intrapopulation improvement compared to ME selection.
An Indirect Method for Estimating Turfgrass Leaf Area Index1
Authors: Kopec D. M. , Norman J. M. , Shearman R. C. , Peterson M. P.
Published: July 2010

Turfgrass leaf area index (LAI) determinations are time consuming, labor intensive, and usually destructive. A system was devised in this study to measure LAI with a nondestructive method. Leaf area index was estimated indirectly based on canopy attenuation of light that was transmitted from a source placed at the base of the turf canopy. This methods essentially the reverse of a procedure used for measuring sunnfleck distribution. The correlation between LAI using the indirect method and LAI measured by use of a leaf area meter was r = 0.93. Leaf area index determinations were made without destroying experimental units. This nondestructive method allows turfgrass canopy growth estimation over time using the same experimental units.
Use of Near Infrared Reflectance Spectroscoppy to Screen Soybean Lines for Plant Nitrogen
Authors: Mündel H. H. , Schaalje G. B.
Published: July 2010

Selecting breeding lines of soybean [Gfycine Max (L.) Merr.] for an enhanced ability to support N fixation by Bradyrhizobium japonicum Jordan requires a fast screening method for determining N content in the plants. The objective of this study was to determine if near infrared spectroscopy (NIRS) could be used as such a method. Two cultivars grown at two locations with 10 inoculation treatments were used for field samples. One cultivar grown at two temperature regimes with 40 N fertilizer treatments was used for the phytotron samples. Samples were ground and regressions were run of log (1/relectance) of up to 19 filters (wavelengths) on a Technicon InfraAlyzer 400 (Technicon Instruments Corp., Tarrytown, NY) to laboratory Kjeldahl N determinations. Filters were selected to optimize regressions; overall stage and/or part regressions as well as individual stage and/or part (R2, R8—overall top growth, R8—seeds, and R8—top growth excluding seeds) regressions were carried out. Tests of homogeneity of regressions showed that stages and/or parts could not be combined, but that field and phytotron‐grown soybean could be combined. Predictions run on random samples were most accurate for N content in seeds and at R2 and least accurate for R8—top growth excluding seeds. Calibrations based on field and phytotron samples from 1 yr were acceptable for predicting N content in a subsequent year. The NIRS calibrations were on the average more highly repeatable for predicting N content than either one of two Kjeldahl determinations.
A Computerized Weighing System Using Barcode Labels for Collection of Harvest Data
Authors: Kephart Kenneth D.
Published: July 2010

The use of computers has eliminated most miscalculations during analysis; however, errors occurring during data collection and collating are still common. Hand recording data is labor intensive, time consuming, and a potential source of errors. Transcriptional mistakes can also occur during manual keyboard entry of data for computer analysis. Time spent on finding and correcting these errors further contribute to labor cost and delays in analysis. To minimize errors in a small‐grain variety performance testing program, a computerized weighing system for the collection of agronomic data was developed using a Radio Shack TRSS0 Model 100 portable computer. Plot identification is facilitated with preprinted self‐adhesive barcode labels scanned with a hand wand connected to the Model 100. Sample weights measured on a digital balance are electronically transmitted to the Model 100 for collection and temporary storage. Data is permanently stored on a microfloppy diskette, and a printed hard copy can be obtained from a printer. Battery operation of the entire system allows portability and flexibility between field and laboratory. Data can be easily retrieved and transferred to either a mainframe or desktop PC computer for analysis.
Analysis of Strategies for Transfer of an Allele for Resistance to Phytophthora Rot in Soybean
Authors: Wehrmann V. K. , Fehr W. R. , Cianzio S. R.
Published: July 2010

It has been reported that seven backcrosses are required to transfer a major allele for resistance to Phytophthora rot, caused by Phytophthora megasperma Drechs. f. sp. glycinea Kuan and Erwin, in soybean [Glycine max (L.) Merr.]. Recently, fewer backcrosses have been used successfully to transfer an allele for resistance to P. megasperma into soybean cultivars. To resolve the difference between the reported research and the practical experience of soybean breeders, this study was conducted to determine in what backcross generation a bulk of phenotypically similar, P. megasperma‐resistant lines will provide the same yield as that of the recurrent parent. The dominant allele Rps1‐k, conferring resistance to specific races of P. megasperma, was transferred from ‘Williams 82’ into two high‐yielding, susceptible genotypes, A78‐123018 and ‘Cumberland’. Thirty‐six random resistant lines from each of five backcross generations of the two populations were evaluated for yield, maturity, lodging, and height in three Iowa environments. On average, 75% of the BC0‐derived lines did not differ significantly from the recurrent parent in yield. The BC1 generation had an average yield equivalent to that of the recurrent parent. The results indicated that, if the donor and recurrent parents differ in yield by 10% or less, one backcross is sufficient to develop a population in which homozygous resistant, phenotypically similar lines can be bulked to replace the recurrent parent.
In Vitro Dry Matter Digestibility, Leaf Anatomy, and Fiber Concentration of a Hybrid between C3 and C3–C4 Panicum Species
Authors: Bohn P. J. , Brown R. H. , Akin D. E.
Published: July 2010

The Panicum genus has C3–C4 species with characteristics between those of C3 and C4 species, and digestibility of C4 or C3–C4 species might be improved by hybridizing with more digestible C3 plants. Leaves of greenhouse‐grown. P. spathellosum Doell (C3–C4), P. boliviense Hack. (C3), and their F1 hybrid were evaluated for characteristics related to forage quality. Leaves were digested in rumen fluid to determinine in vitro dry matter digestion (IVDMD) and degradation of specific leaf tissues. The hybrid was intermedite and differed (P < 0.05) from its parents in leaf IVDMD with values of 642 g kg−1 compared to 630 and 709 g kg−1 for the C3–C4 and C3 species, respectively. The hybrid was also intermediate (P < 0.05) to its parents in the percentage of sclerenchyma, lignified bundle tissue, phloem, abaxial epidermis, and mesophyll. The hybrid had 18.8% of its leaf cross‐section as parenchyma bundle sheath compared 15.0% for P. boliviense and 16.5% for P. spathellosum. Neutral detergent fiber was 583 g kg−1 for the hybrid compared to 511 and 568 g kg−1 for the C3 and C3–C4 parents, respectively. Acid detergent fiber was 61 g kg−1 greater than for the C3 parent. The hybrid showed greater loss of mesophyall and epidermal tissues than P. spathellosum in top leaves, but only for abaxial epidermis in bottom leaves. Hybridization affected leaf anatomy and fiber characteristics related to digestibility. However, degradation of specific tissues did not follow consistent trends, suggesting that intrinsic factors within cell walls can override anatomical changes.
Seed Treatment for Control of Irondeficiency Chlorosis of Soybean
Authors: Karkosh A. E. , Walker A. K. , Simmons J. J.
Published: July 2010

Several cultural practices have been employed as an attempt to limit yield reductions associated with Fe‐deficiency chlorosis of soybean [Glycine max (L.) Merr.]. Seed treatment offers another approach to economically applying Fe to soybean grown on calcareous soils. The Fe chelate, Fe‐EDDHA [sodium ferric ethylenediamine di‐(o‐hydroxyphenylacetate)], was evaluated as a seed treatment on soybean genotypes with varying levels of resistance to Fe‐deficiency chlorosis. A rate of 10 g Fe‐EDDHA kg−1 seed was applied to six soybean genotypes. The field study was conducted over 2 yr on two highly calcareous soils, a Harps clay loam (Typic Calciaquoll) and a Canisteo clay loam (Typic Haplaquoll). The seed treatment did not produce significantly higher yields for the susceptible genotypes, but did produce significantly higher yields for the more resistant genotypes. Iron seed treatment should not be used with susceptible genotypes, but seed treatment on genotypes with some resistance would be economical on some calcareous soils.
Patterns of Total Peroxidase Activity and Isozyme Complement During Development of Selected Maturity Genotypes of Sorghum
Authors: Pao Ching‐I , Morgan Page W.
Published: July 2010

Changes in peroxidase activity were studied in two maturity genotypes of sorghum [Sorghum bicolor (L.) Moench] grown under 10‐and 14‐h photoperiods. The rationale was that peroxidase activity or isozyme complement may represent a means to characterize developmental changes in the maturity genotypes and, possibly, a system to regulate indoleacetic acid (IAA) levels. The maturity genotypes 100M and 38M are near isogenic except for the differences at three of the maturity gene loci. Tissue extracts were separated into soluble (cytoplasm) and ionically or covalently bound wall fractions, which were assayed for total peroxidase activity detected in the cytoplasm and cell wall fractions but not in organelle fractions. On a fresh weight basis, total peroxidase activity did not show consistent changes with age and there were no differences between genotypes. However, on a specific activity basis, the ionically bound peroxidase exhibited the highest activity, which consistently peaked near the time of floral initiation of 38M under both photoperiods and 100M under 10‐h photoperiods. A similar activity profile was not observed for 100M, which remained vegetative under 14‐h photoperiods. The peroxidase isozyme complement was studied by gel electrophoresis with 100M grown under 10‐h photoperiods as a model system. There were modest quantitative changes; however, qualitative changes were more striking because they occurred near the time of floral initiation on Day 30. In both soluble and covalently bound fractions, the predominant qualitative changes were observed for the cationic isozymes on Days 25 and 30. The obvious changes in specific activity and isozyme pattern imply that peroxidases may play an important role in the control of transition processes from vegetative to reproductive stages.
LY195259, New Chemical Hybridizing Agent for Wheat
Authors: Tschabold E. E. , Heim D. R. , Beck J. R. , Wright F. L. , Rainey D. P. , Terando N. H. , Schwer J. F.
Published: July 2010

LY195259, 5‐(Aminocarbonyl)‐l‐(3‐methylphenyl)‐1H‐pyrazole‐4‐carboxylic acid, has been physically characterized in the laboratory and has been evaluated as a male sterilizing agent under greenhouse and field conditions on several plant species, including wheat (Triticum aestivum L.). Male sterilizing agents are useful in producing hybrid seed. Under optimum conditions, the compound when applied as a foliar spray to wheat at rates as low as 1.12 kg a.i. ha−1 has produced > 95% male sterility. It also has been effective when applied in the spring as soil‐surface treatments. Over 100 cultivars have been tested and had at least 90% male sterility when treated with LY195259. Some crosses made with wheat cultivars treated with LY195259 and a properly nicked pollen source with good pollen load had 80% of the seed set of the selfed male parent. No physical distortion of the hybrid seed was apparent, and no other phytotoxic effects were visually evident from rates as high as 3 times the mean effective dose.
Genetic Analysis of Low Linolenic Acid Levels in the Soybean Line PI 361088B
Authors: Rennie B. D. , Zilka J. , Cramer M. M. , Beversdorf W. D.
Published: July 2010

The soybean (Glycine max (L.) Merr.) line PI 361088B was identified as having a linolenic acid level (38.1 g kg−1) that was about half that of ‘Maple Arrow’ (78.1 g kg−1), but similar to that of the mutagen‐induced line C1640 (37.6 g kg−1). Our objective was to determine the inheritance of low linolenic acid levels in PI 361088B, and to determine the genetic basis of this trait relative to the Fan locus known to influence linolenic acid levels in C1640. The F2 and F3 segregation data from crosses between PI 361088B and Maple Arrow or ‘Ace’, indicate that linolenic acid levels in PI 361088B are influenced by alleles, at a single locus, acting in an additive manner. Crosses were made between C1640 and a low linolenic acid selection from a three‐way cross involving PI 361088B. The F2 progeny of the cross, [(Ace ✕ PI 361088B) ✕ OAC 84‐06] ✕ C1640, did not segregate for linolenic acid levels indicating that the low levels in both PI 361088B and C1640 are controlled by alleles at the same locus. A linkage assay indicated that the Fan locus segregates independently of the Dial, Enp, Idh1, and Pgm1 loci, and that the Fan locus is linked to the Idh2 locus with a recombination frequency of 28.2 ± 2.7%. No other linkages have been established for these two loci; they therefore are assigned to linkage group 17.
Effect of Prolificacy on Grain Yield and Root and Stalk Strength in Maize
Authors: Brotslaw D. J. , Darrah L. L. , Zuber M. S. , Krause G. F.
Published: July 2010

Poor root and stalk strength have contributed to limited use of prolific maize (Zea mays L.) hybrids by farmers. Knowledge of the relationships of yield, prolificacy, and plant standability permits appropriate emphasis in selection programs. Three prolific maize populations and one nonprolific hybrid (B73 ✕ Mo17) were grown a randomized complete block design in two environments to measure the effect of total grain yield and number of ears per plant on stalk and root quality. Data were recorded on an individual plant basis for date of anthesis and silk emergence, total grain yield and grain yield among ears of a plant, ear height, vertical root pulling resistance, and stalk crushing strength. All competitive plants were harvested and on the basis of overall frequency distribution of grain yield between ears, were subdivided into one‐ and two‐eared prolificacy levels for variance and mean analysis. Two‐eared plants had significantly higher mean grain yields, closer synchrony between anthesis and silking, and greater ear heights than one‐eared plants for the three prolific populations. No significant differences were found between one‐ and two‐eared plants for vertical root pulling resistance or stalk crushing strength. Simple correlations for root pulling resistance and stalk crushing strength with percent of total grain yield in top ear were generally nonsignificant for the three prolific populations and when significant, were smaller than the same correlations with total yield.
Response of Current Midwestern Soybean Cultivars to Late Planting
Authors: Raymer P. L. , Bernard R. L.
Published: July 2010

Soybean [Glycine max (L.) Merr.] is grown in the Midwestern USA primarily as a full‐season crop and only to a limited extent as a double crop following small grains. Development of cultivars specifically adapted to later planting dates commonly associated with double‐crop production has been suggested as a means to expand double‐crop hectarage in this area. To determine if currently used soybean cultivars differ in their adaptation to late planting and if any specific plant traits are related to improved performance under late‐planted conditions, 16 soybean cultivars were evaluated at both conventional (May) and late (late June to early July) planting dates in 1979, 1980, and 1981. Cultivar by planting date interactions were found for days to maturity, height at maturity, seed quality, and seed mottling, but not for yield, days to flowering, height at flowering, lodging, and weight per 100 seeds. All cultivars suffered substantial and similar yield reductions when planted late. Phenotypic correlation coefficients of cultivar performance between the two planting dates were positive and highly significant for all plant traits measured. The relationship of yield with various plant traits varied greatly from year to year and no differences in these relationships were observed between the two planting dates. These results do not furnish any evidence to justify a separate breeding program for the development of double‐crop cultivars adapted to the Midwest. The lack of a strong cultivar by planting date interaction for yield and the lack of any strong associations of specific plant characteristics with yield in a late‐planted environment imply that testing in a conventional early‐planted environment will be effective in identifying lines that perform well in either full‐season or double‐crop environments.
Agronomic Evaluation of Oat Cultivars with Substituted Avena fatua and A. sterilis Cytoplasms
Authors: Rines H. W. , Halstead R. P.
Published: July 2010

Genetic diversity in cytoplasms may potentially reduce the vulnerability of a crop to an epiphytotic and also increase variability available for trait improvement. The objectives of this study were to increase the cytoplasmic diversity available in cultivated oat (Avena sativa L.) and to test effects of substituted wild oat cytoplasms on grain yield and other agronomic traits. Cytoplasm substitution lines were developed by five to six backcrosses of four oat cultivars into cytoplasms of five A. fatua L. and three A. sterilis L. wild oat accessions. Two to six lines of various alloplasmic combinations were compared to their respective euplasmic A. sativa recurrent parents in hill plot tests at two locations in 1985 and one location in 1986. The A. fatua and A. sterilis cytoplasms generally did not affect grain yield, aboveground biomass production, height, heading date, harvest index, or seed weight. One alloplasmic combination, among 24 tested, consistently yielded significantly less than its euplasmic A. sativa parent, but none yielded significantly more. The few instances where particular alloplasmic combinations differed from their euplasmic A. sativa parents may have resulted from residual nuclear contributions from the cytoplasm donor. The general lack of detrimental effects of substituted A. fatua and A. sterilis cytoplasms indicate that they may be useful for broadening the cytoplasmic diversity of oat.