bluuebunny/crossref_metadata_2025 huggingface dataset:
Paroxysmal Events in Infants: Persistent Eye Closure Makes Seizures Unlikely
Authors: Korff Christian M. , Nordli Douglas R.
Published: September 2005

Objective. Paroxysmal events are frequent in infancy. A precise diagnosis is often difficult to assign despite adequate history and physical examination. Certain clinical signs may help to suggest the diagnosis, thereby avoiding unnecessary and costly investigations. The aim of this study was to determine the frequency of eye opening during infantile seizures and evaluate the potential usefulness of this simple observation in the differential diagnosis of acute events in infants.

Methods. We performed a retrospective video electroencephalogram review of the seizures recorded in infants at our Epilepsy Center, paying specific attention to eye opening.

Results. Ninety-one seizures in 69 infants were included. Eyes were open in 85 (93.4%) cases.

Conclusions. Infants whose eyes are closed throughout the paroxysmal event are most likely not having seizures.
Lead Exposure in Children: Prevention, Detection, and Management
Authors:   Committee on Environmental Health
Published: September 2005

This Policy Statement was retired April 2013.

Fatal lead encephalopathy has disappeared and blood lead concentrations have decreased in US children, but approximately 25% still live in housing with deteriorated lead-based paint and are at risk of lead exposure with resulting cognitive impairment and other sequelae. Evidence continues to accrue that commonly encountered blood lead concentrations, even those less than 10 μg/dL, may impair cognition, and there is no threshold yet identified for this effect. Most US children are at sufficient risk that they should have their blood lead concentration measured at least once. There is now evidence-based guidance available for managing children with increased lead exposure. Housing stabilization and repair can interrupt exposure in most cases. The focus in childhood lead-poisoning policy, however, should shift from case identification and management to primary prevention, with a goal of safe housing for all children.
Trends in Contacts With Mental Health Professionals and Cost Barriers to Mental Health Care Among Adults With Significant Psychological Distress in the United States: 1997–2002
Authors: Mojtabai Ramin
Published: September 2005

Objectives. I assessed recent trends in prevalence of any contact with mental health professionals and nonuse of mental health care or prescription medications owing to cost among adults with significant psychological distress.

Methods. In samples drawn from the National Health Interview Survey of 1997–2002, multiple logistic regression analysis was used to examine the association of survey year with mental health professional contacts and nonuse of mental health care or prescription medications owing to cost.

Results. The prevalence of any contact with mental health professionals increased from 29.1% in 1997 to 35.5% in 2002 (P<.05). The prevalence of nonuse of services because of cost also increased—from 15.6% to 20.0% for mental health care (P<.05) and from 27.7% to 34.1% for medication use (P<.001). Age, racial/ethnic, income, and insurance status disparities in receiving care persisted over the study period.

Conclusions. The number of individuals in need of mental health care who contacted mental health professionals grew in recent years, as did the number of individuals who encountered cost barriers to such care. Barring dramatic improvements in health insurance coverage, more individuals will likely face such barriers in coming years.
Functional Limitations Among Older American Indians and Alaska Natives: Findings from the Census 2000 Supplementary Survey
Authors: Fuller-Thomson Esme , Minkler Meredith
Published: September 2005

The objectives of this study were to determine the national prevalence and profile of American Indian and Alaska Natives with functional limitations. Data were obtained from 4763 American Indian and Alaska Native respondents aged 45 years or older in the Census 2000 Supplementary Survey. Functional limitations were reported by 28% of American Indian and Alaska Natives aged 45 years or older. These individuals were poorer, older, less educated, and less likely to be married or employed than American Indian and Alaska Natives without such limitations (for all comparisons, P < .001). American Indian and Alaska Natives have high disability rates, and many are not receiving benefits for which they qualify
Public Health Approach to Emerging Infections Among Pregnant Women
Authors: Rasmussen Sonja A. , Hayes Edward B.
Published: September 2005

As public health professionals respond to emerging infections, particular attention needs to be paid to pregnant women and their offspring. Pregnant women might be more susceptible to, or more severely affected by, emerging infections. The effects of a new maternal infection on the embryo or fetus are difficult to predict. Some medications recommended for prophylaxis or treatment could harm the embryo or fetus. We discuss the challenges of responding to emerging infections among pregnant women, and we propose strategies for overcoming these challenges.
Prevalence of Concurrent Hearing and Visual Impairment in US Adults: The National Health Interview Survey, 1997–2002
Authors: Caban Alberto J. , Lee David J. , Gómez-Marín Orlando , Lam Byron L. , Zheng D. Diane
Published: September 2005

Analysis of data from a nationally representative sample of US adults (n=195801) showed that concurrent hearing and visual impairment prevalence rates were highest for participants older than 79 years of age (16.6%); a 3-fold increase in age-adjusted rates of reported hearing and visual impairment was observed for Native Americans compared with Asian Americans. Research on preventing concurrent hearing and visual impairment and countering its consequences is warranted, especially in population subgroups, such as Native and older Americans.
Running on Empty: Families, Time, and Workplace Injuries
Authors: Boden Leslie I.
Published: September 2005

Over the past 5 decades, more women have entered the labor force, and more households have been headed by single parents. Both trends have substantially reduced parents’ free time, creating added strain in the event of family health problems, including work-related injuries and illnesses. This commentary presents evidence about the impact of occupational injuries on today’s families.

In addition to losing considerable income, injured parents are less able to do household work, and other family members are often called on to care for them. Family members cut back on their paid, school, and household work to fill in for the injured parent. This suggests the importance of policies to help today’s time-strapped families cope with major family health events.
Young Adult Caregivers: A First Look at an Unstudied Population
Authors: Levine Carol , Hunt Gail Gibson , Halper Deborah , Hart Andrea Y. , Lautz Jessica , Gould David A.
Published: September 2005

Objectives. We examined the prevalence, characteristics, and responsibilities of young adults aged 18 to 25 years who are caregivers for ill, elderly, or disabled family members or friends.

Methods. We analyzed 2 previously published national studies (from 1998 and 2004) of adult caregivers.

Results. Young adult caregivers make up between 12% and 18% of the total number of adult caregivers. Over half are male, and the average age is 21. Most young adults are caring for a female relative, most often a grandmother. Young adult caregivers identified a variety of unmet needs, including obtaining medical help, information, and help making end-of-life decisions.

Conclusions. Analysis of these 2 surveys broadens our understanding of the spectrum of family caregivers by focusing on caregivers between the ages of 18 and 25 years. The high proportion of young men raises questions about the appropriateness of current support services, which are typically used by older women. Concerted efforts are essential to ensure that young adults who become caregivers are not deterred from pursuing educational and career goals.
Genotype × Environment Interactions for a Diverse Set of Sweetpotato Clones Evaluated across Varying Ecogeographic Conditions in Peru
Authors: Grüneberg Wolfgang J. , Manrique Kurt , Zhang Dapeng , Hermann Michael
Published: September 2005

Sweetpotato [Ipomoea batatas (L.) Lam.] is cultivated across a wide range of agrogeographical conditions. The objectives of this study were to analyze genotype × environment (G × E) interactions for sweetpotato yield (i.e., storage root yield, biomass, harvest index) and nutritional traits [i.e., root dry matter (RDM), starch (STA), and β‐carotene (BCR) content; and leaf carotene (BCL) and chlorophyll (CHL) content] in multienvironmental trials (MET) across ecogeographic regions. Nine clones of diverse origins were tested and compared with check clones at seven locations in Peru using two N treatments (N = 0 or 80 kg ha−1). The G × E analysis was conducted with regression, additive main effects and multiplicative interaction (AMMI), and cluster analyses. The G × E interactions were smaller than the genetic variation of nutritional traits. The G × E interactions were larger or nearly equal to the genetic variation of yield traits (except harvest index), and were mainly determined by subsets of genotypes and environments. The contribution of N input to G × E was often not significant. Genotypes were observed with wide adaptation and high yields (about 19 to 22 Mg ha−1) across all three environmental groups that were derived from the cluster analysis. However, a specifically adapted genotype was observed with considerable yield advantage over all widely‐adapted genotypes in low‐yielding environments (from 9 to 18 Mg ha−1). Locations differed in their selection ability for storage root yield. We concluded that it is possible to breed for high yield and wide adaptability in sweetpotato in Peru, and it can be ensured that low‐yielding or marginal environments are not neglected in breeding efforts.
Isolation of Maize from Pollen‐Mediated Gene Flow by Time and Distance
Authors: Halsey Mark E. , Remund Kirk M. , Davis Christopher A. , Qualls Mick , Eppard Philip J. , Berberich Sharon A.
Published: September 2005

Development of improved genetic traits in maize (Zea mays L.) requires robust measures to prevent pollen‐mediated gene flow (PMGF) and assure isolation of new traits, whether these traits are the result of conventional breeding or of modern genetic techniques. Studies were conducted in California and Washington to evaluate the relationship of distance and temporal separation for isolation from PMGF. Kernel color was used to detect outcrossing from source plots of 0.4 to 1.2 ha in size to receptor plots planted at distances up to 750 m and planting intervals of up to 3 wk from the pollen source. Outcrossing from source to receptor plots was observable to 0.0002% (1 kernel in ≈500000 kernels). Increasing temporal separation reduced the distance required to achieve genetic isolation. Outcrossing was <0.01% at 500 m when source and receptors flowered at the same time, whereas this level of confinement was achieved at 62 m or less when 2 wk of temporal separation was used. No outcrossing was detected at 750 m and 2 wk of temporal separation. This is the first practical evaluation of time and distance acting together to achieve genetic purity in maize.
Barley HVA1 Gene Confers Salt Tolerance in R3 Transgenic Oat
Authors: Oraby Hesham F. , Ransom Callista B. , Kravchenko Alexandra N. , Sticklen Mariam B.
Published: September 2005

A major cause of oat crop yield loss worldwide is osmotic stress due to drought and/or salinity. This study investigated the third generation of transgenic oat (Avena sativa L.) expressing barley HVA1 stress tolerance, β‐glucuronidase (uidA; gus) and bar herbicide resistance genes. Transgenic plants showed normal 9:7 third generation inheritance for glufosinate ammonium herbicide resistance. Molecular and histochemical studies confirmed the presence and stable expression of all three genes. Compared with the nontransgenic control plants, transgenic R3 plants exhibited greater growth and showed a significant (P < 0.05) increase in tolerance to salt stress conditions (200 mM NaCl) for traits including number of days to heading, plant height, flag leaf area, root length, panicle length, number of spikelets/panicle, number of tillers/plant, number of kernels/panicle, 1000‐kernel weight, and kernel yield/plant.
Alternative Maize Heterotic Patterns for the Northern Corn Belt
Authors: Melani M. D. , Carena M. J.
Published: September 2005

Development of maize (Zea mays L.) inbred lines is based on the identification and utilization of heterotic groups and patterns. The objective of this research was to identify alternative heterotic patterns for the northern Corn Belt. Ten maize populations [BS5, BS21(R)C7, BS22(R)C7, CGL(S1–S2)C5, CGSS(S1–S2)C5, LEAMING(S)C4, NDSAB(MER)C12, NDSCD(M)C10, NDSG(M)C15, and NDSM(M)C7] were crossed in a diallel mating design. The 45 F1 crosses along with nine checks were evaluated in experiments with two replicates at each of four North Dakota and three Iowa locations in 2002. Data were collected for grain yield, harvest grain moisture, and root and stalk lodging. Analyses of variance were performed following the Gardner and Eberhart Analysis III model. Differences among genotypes existed for all of the traits, and the general combining ability (GCA) sums of squares were larger than the specific combining ability (SCA) sums of squares, indicating the predominance of additive genetic effects. Alternative heterotic patterns to ‘Iowa Stiff Stalk Synthetic’ (BSSS) × ‘Lancaster Sure Crop’ (LSC) were found for grain yield among early‐maturing populations. The most promising crosses were those in which BS21(R)C7 was combined with CGL(S1–S2)C5, BS22(R)C7, NDSG(M)C15, LEAMING(S)C4, CGSS(S1–S2)C5, and NDSAB(MER)C12, and the heterotic pattern formed by BS22(R)C7 and LEAMING(S)C4. A strong association was found between the grain yield of populations per se and their GCA for harvest grain moisture. The population CGSS(S1–S2)C5 was the earliest among the 10 populations studied and had the best GCA value for grain moisture.
Whole‐Farm Perspectives of Nutrient Flows in Grassland Agriculture
Authors: Rotz C. A. , Taube F. , Russelle M. P. , Oenema J. , Sanderson M. A. , Wachendorf M.
Published: September 2005

Grassland agriculture is an important industry for livestock production and land management throughout the world. We review the principles of nutrient cycling in grassland agriculture, discuss examples of grassland farming systems research, and demonstrate the usefulness of whole‐farm simulation for integrating economic and environmental components. Comprehensive studies conducted at the Karkendamm experimental farm in northern Germany and the De Marke experimental farm in the Netherlands have quantified nutrient flows and developed innovative strategies to reduce nutrient losses in grassland farming systems. This research has focused on improving the utilization of manure nutrients on the farm by including grain crops in cropping systems with grassland and by incorporating manure handling techniques that reduce nitrogen losses. Although the information generated in experimental farms is not always directly applicable to other climates and soils, it is being transferred to other regions through computer simulation. A whole‐farm model calibrated and verified with the experimental farm data is being used to evaluate and refine these strategies for commercial farms in other areas. Simulation of farms in northern Europe illustrate that on the sandy soils of this region, maize (Zea maysL.) silage can be used along with grasslands to increase farm profitability while maintaining or reducing nutrient loss to the environment. Use of cover crops, low emission barns, covered manure storages, and direct injection of manure into soil greatly reduces N losses from these farms, but their use creates a net cost to the producer. By integrating experimental farm data with whole‐farm simulation, more sustainable grassland production systems can be cost‐effectively evaluated, refined, and transferred to commercial production.
Agronomic Performance of Recombinant Inbred Line Populations Segregating for Isoflavone Content in Soybean Seeds
Authors: Primomo Valerio S. , Poysa Vaino , Ablett Gary R. , Jackson Chung-Ja , Rajcan Istvan
Published: September 2005

Soybean [Glycine max (L.) Merrill] seeds contain isoflavones, which have been associated with positive health effects in human adults but a negative effect on infants. Increasing or decreasing isoflavone content in the seed would be desirable; however, it is not known what impact this would have on agronomic and other seed quality traits. The main objective of this study was to determine if isoflavone content in soybean seeds was associated with changes in agronomic and seed quality traits. Recombinant inbred lines (RILs) with “high” (n = 35), “intermediate” (n = 35), and “low” (n = 35) isoflavone content, were selected from three F4:5 populations grown in 2000 and planted at three locations in southern Ontario in 2002. There were significant differences among populations, environments, and their interaction for isoflavone content. “High” and “low” phenotypic classes were significantly different for maturity in all three populations. Despite a positive correlation between yield and isoflavones, several RILs with decreased isoflavone content (970 μg g−1) were identified with yields (4222 kg ha−1) comparable to high‐yielding cultivars. Isoflavone content had minimal effects on oil content, seed quality, and weight. Population 1 showed a significant negative association between isoflavone and protein content, whereas Pop. 2 and Pop. 3 did not. RILs were identified with high isoflavone and protein content ranging from 1746 to 1851 μg g−1 and 431 to 442 g kg−1, respectively. It was possible to develop soybean with desirable isoflavone content in the seed and superior agronomic and seed quality traits.
Structure of Flavonoid 3′‐Hydroxylase Gene for Pubescence Color in Soybean
Authors: Toda Kyoko , Akasaka Maiko , Dubouzet Emilyn G. , Kawasaki Shinji , Takahashi Ryoji
Published: September 2005

The T locus of soybean [Glycine max (L.) Merr.] controls pubescence and seed coat color and it is presumed to encode a flavonoid 3′‐hydroxylase (F3′H). Dominant T and recessive t allele of the locus produce tawny and gray pubescence, respectively. Alleles at the T locus are associated with chilling tolerance. We previously cloned the entire cDNA of F3′H gene (sf3′h1) from soybean. In this report, the entire F3′H gene was characterized by isolating two genomic clones covering the entire gene. Sequence analysis revealed that F3′H gene consists of three exons and two introns distributed in a 8500‐bp DNA segment. The promoter region of the F3′H gene contains a putative G‐box, two MYB‐binding domains, and TA‐repeats. The structure and number of the TA repeats was cultivar‐dependent and highly polymorphic. A pair of simple sequence repeat (SSR) primers designated as SoyF3′H was developed to flank the TA‐repeats. The SSR band polymorphism cosegregated with genotypes at T locus in 89 F2 plants segregating for the T locus. The SSR marker may be a useful internal marker of the F3′H gene and is applicable even among cultivars with similar pubescence color. The promoter sequence information obtained in this report may be useful for investigations on the transcriptional control of F3′H gene as well as transgenic experiments to clarify the relationship between F3′H gene and chilling tolerance in soybean.
Comparative Effects of the Sorghum bmr‐6 and bmr‐12 Genes: I. Forage Sorghum Yield and Quality
Authors: Oliver A. L. , Pedersen J. F. , Grant R. J. , Klopfenstein T. J.
Published: September 2005

Brown midrib (bmr) forages usually contain less lignin and exhibit increased digestibility. Recent research has identified the modifications in biochemical pathways resulting from bmr mutations. In sorghum [Sorghum bicolor (L) Moench.], bmr‐6 has been linked to a decrease in cinnamyl alcohol dehydrogenase (CAD) activity. The allelic bmr‐12 and bmr‐18 genes decrease caffeic acid O‐methyl transferase (OMT) activity. There has been only limited research comparing bmr genes to each other and wild type in isogenic sorghum. The objective of this study was to determine the impact of bmr‐6 and bmr‐12 on forage yield and quality in these genetic backgrounds: ‘Atlas’, ‘Early Hegari‐Sart’, ‘Kansas Collier’, and ‘Rox Orange’. Height, lodging, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), in vitro NDF digestibility (IVNDFD), and dry matter (DM) yield were measured in a split‐plot experiment replicated four times in each of four environments with lines being whole‐plots and genotypes (wild type, bmr‐6, and bmr‐12) being subplots. Brown midrib genes generally had negative agronomic impact, but these were not uniformly expressed across backgrounds. The bmr‐6 gene generally resulted in a shorter plant and less DM yield, but did not reduce ADL. The bmr‐12 gene generally resulted in reduced ADL, later maturity, and reduced or equivalent DM yield when compared with the wild type. There is a more digestible NDF fraction in both bmr‐6 and bmr‐12 forage sorghums. When all data are considered in aggregate, the bmr‐12 gene appears superior to the bmr‐6 gene in terms of less negative impact on agronomic performance and greater positive impact on ADL content and fiber digestibility.
Ear Position, Leaf Area, and Contribution of Individual Leaves to Grain Yield in Conventional and Leafy Maize Hybrids
Authors: Subedi K. D. , Ma B. L.
Published: September 2005

The contribution of individual leaves and the extra leaves above the ear to dry matter (DM) accumulation and grain yield in Leafy maize (Zea mays L.) is not well documented. A field experiment was conducted for two growing seasons (2003 and 2004) at Ottawa, Canada, to determine whether additional leaves above the ear in a Leafy hybrid contribute more to grain yield than in a conventional hybrid and to assess the importance of individual leaves above and below the ear. At silking, 10 defoliation treatments were imposed in a conventional (Pioneer 3893) and a Leafy (Maizex LF850‐RR) hybrid. Total number of leaves per plant, position of the primary ear height, and the area and DM of each removed leaf were measured at silk stage. At physiological maturity, number of kernels per plant, kernel DM, and whole plant DM were determined. Despite the Leafy hybrid having a 25% greater number of leaves, 26 to 40% more green leaf area, and 16 to 41% more total plant DM at silking than the conventional hybrid, there was no difference in total DM and grain yield at physiological maturity, indicating a situation of sink limitation in the Leafy hybrid. Removal of all leaves below the earleaf and earleaf alone in the conventional hybrid caused 19 to 26% and 17 to 25% reduction in grain yield, respectively, while there was no any notable effect of these treatments in the Leafy hybrid. When all leaves above the earleaf were removed, kernel number and kernel DM were reduced by 84 to 94% in the Leafy hybrid compared with a 40 to 50% reduction in the conventional hybrid. We conclude that the large number of leaves in the Leafy maize gave no additional advantage in terms of grain yield and total DM production and the earleaf and leaves below the ear‐node were of less importance in the Leafy hybrids than in the conventional hybrid.
Comparative Effects of the Sorghum bmr‐6 and bmr‐12 Genes: II. Grain Yield, Stover Yield, and Stover Quality in Grain Sorghum
Authors: Oliver A. L. , Pedersen J. F. , Grant R. J. , Klopfenstein T. J. , Jose H. D.
Published: September 2005

Nearly 3 million hectares of grain sorghum [Sorghum bicolor (L). Moench] are harvested in the USA each year. It may be possible to add value to crop and animal systems by enhancing the digestibility of the stover residue by the use of brown midrib (bmr) genes if grain yields can be maintained. The objectives of this study were to evaluate the effect of bmr‐6 and bmr‐12 genes on grain yield of sorghum and to evaluate the effect of the bmr genes on stover yield and quality in these genetic backgrounds: ‘Wheatland’, ‘Redlan’, RTx430, Tx623, Tx630, Tx631, and the hybrid AWheatland × RTx430. Plant height, maturity, grain yield and test weight, stover neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and in vitro NDF digestibility (IVNDFD) were measured in split‐plot experiments replicated four times in each of four environments with lines being whole‐plots and genotypes being subplots. Brown midrib genes reduced grain yield and residue yield in the lines; however, yield reduction was not observed in the bmr‐12 AWheatland × RTx430 hybrid. The bmr‐12 near‐isolines generally had lowest stover lignin content and highest fiber digestibility, bmr‐6 was intermediate, and wild‐type counterparts had highest lignin content and lowest fiber digestibility. When all data are considered, the bmr‐12 gene appears superior to the bmr‐6 gene in terms of potentially adding value to the stover of grain sorghum for use in crop/animal systems. The variable expression of bmr‐12 and bmr‐6 in different lines indicates that selection of compatible genetic backgrounds will be critical in determining the realized impact on value.
Forage Nutritive Value and Morphology of Three Old World Bluestems under a Range of Irrigation Levels
Authors: Philipp D. , Allen V. G. , Mitchell R. B. , Brown C. P. , Wester D. B.
Published: September 2005

Introduced forages offer alternatives to traditional cropping systems in the semiarid Texas High Plains, but effects of irrigation on nutritive value are not well known. Three old world bluestem (Bothriochloa) species [B. bladhii(Retz) S.T. Blake ‘WW‐B. Dahl’,B. ischaemum(L.) Keng. var.ischaemum(Hack.) ‘WW‐Spar’, andB. caucasica(Trin.) C.E. Hubbard ‘Caucasian’] were surface drip‐irrigated with zero (dryland) and low, medium, and high irrigation levels, to determine nutritive value and morphological development in 2001 to 2003 under a completely randomized block design, a split‐plot treatment arrangement, and three replicates. Water applied in the high treatment was 100% replacement of potential evapotranspiration minus precipitation. Medium and low treatments were 66 and 33% of the high treatment. Dry matter digestibility (DMD) of all species was higher (P< 0.05) at low irrigation than at other levels (580, 560, 550, and 570 g kg−1for low, medium, high, and dryland, respectively; SE = 4.0). Dahl was higher (P< 0.05) in crude protein (87 g kg−1) than Spar (76 g kg−1) and Caucasian (75 g kg−1; SE = 2.0) during the growing season. In all species, total nonstructural carbohydrates and DMD declined while neutral detergent fiber and acid detergent fiber increased with increasing irrigation. Before hay harvest, leaf blade:stem‐plus‐sheath ratio declined also, but after hay harvest, effects of irrigation were less consistent. Results suggested that irrigation likely affected nutritive value through effects on plant morphology and physiological age. Thus, irrigation strategies and species selection may aid in optimizing forage quality.
Resistance to Soybean Aphid in Early Maturing Soybean Germplasm
Authors: Mensah Clarice , DiFonzo Christina , Nelson Randall L. , Wang Dechun
Published: September 2005

Since 2000, the soybean aphid (Aphis glycines Matsumura) has become a major pest of soybean [Glycine max (L.) Merr.] in North America. In the USA, there are currently no commercial soybean cultivars with aphid resistance and there are no reported resistance sources in early maturing soybean germplasm. The objectives of this study were to identify sources and types of resistance to soybean aphid from early maturing soybean germplasm. Over a 2‐yr period, 2147 soybean accessions from maturity group (MG) 0 to III, originally from northern China, were evaluated for aphid resistance in a greenhouse and in field cages. The plants were hand‐inoculated and aphid populations were evaluated 10 d after inoculation. A damage index (0–100%) was calculated for each accession. After 2 yr of evaluation and confirmation in choice tests, four MG III accessions from Shandong province, PI 567543C, PI 567597C, PI 567541B, and PI 567598B, were found to be resistant to the soybean aphid. Two of these accessions, PI 567541B and PI 567598B, possessed antibiosis resistance, preventing the aphids from reproducing on the plants in a no‐choice study. PI 567543C and PI 567597C possessed antixenosis resistance. These resistant sources can be used to develop commercial cultivars with aphid resistance for the North Central states.
A Curated Internet Database of Oat Pedigrees
Authors: Tinker Nicholas A. , Deyl Jitka K.
Published: September 2005

Plant pedigree data are valuable for crop improvement and for genetic studies. We describe the development of an extensive, internationally relevant database of oat (Avena sativa L.) pedigrees. The database contains documented records of oat varieties and breeding lines, their ancestors, and various names that have been applied to them. The database is searchable through a simple interface located at http://avena.agr.gc.ca; verified 13 June 2005. This interface allows keyword searches for variety names and creates diagrams showing known ancestors or descendants of any variety.
Molecular Mapping and Allelic Relationships of Russian Wheat Aphid–Resistance Genes
Authors: Liu X. M. , Smith C. M. , Friebe B. R. , Gill B. S.
Published: September 2005

The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), is a serious economic pest of wheat (Triticum aestivum L.) worldwide. Although resistant wheat cultivars provide good control of RWA, genetic characterization is critical to the continual use of aphid‐resistance genes. The objective of this study was to determine the chromosome location and the genetic relationships of the RWA‐resistance genes Dn1, Dn2, Dn4, Dn5, Dn6, Dnx, and several uncharacterized Dn genes. Molecular mapping demonstrated that Dn genes in four uncharacterized wheat lines (PI 47545, PI 222666, PI 222668, and PI 225245) as well as Dn1, Dn2, Dn5, Dn6, and Dnx are tightly linked to microsatellite markers Xgwm44 and Xgwm111 Deletion bin mapping assigned Xgwm44 physically in the region distal to the breakpoints 7DS‐4 (FL 0.61) and Xgwm111 distal to 7DS‐5 (FL 0.36) of wheat chromosome arm 7DS. Allelism tests detected no segregation for susceptibility among TC1F1 plants from the test crosses or among F2 plants derived from intercrosses between wheat lines containing each of these known Dn genes. Both marker‐linkage analyses and allelism tests revealed that all these Dn genes are clustered in a region linked to Xgwm111 and are either alleles of a single locus or are closely related members of a Dn gene family. Dn4 and the uncharacterized Dn gene in PI 151918 are either allelic or linked on wheat chromosome 1DS. The linked markers and genetic relationships of these Dn genes will greatly facilitate their use in wheat breeding and the deployment of aphid‐resistant cultivars.
Pedigree‐ vs. DNA Marker‐Based Genetic Similarity Estimates in Cotton
Authors: Van Becelaere Guillermo , Lubbers Edward L. , Paterson Andrew H. , Chee Peng W.
Published: September 2005

Knowledge of genetic diversity and relationships among breeding materials is essential to the improvement of crop species. Genetic similarity estimates among cultivars are helpful to select parental combinations for segregating populations so as to maintain genetic diversity in a breeding program. The objective of this study was to determine the correspondence between pedigree‐ and restriction fragment length polymorphism–based genetic similarity (RFLP‐GS) estimates for a set of 36 Upland cotton (Gossypium hirsutum L.) cultivars. Coefficients of parentage (COPs) and genetic similarity estimates based on 261 codominant RFLP markers for all possible pairs of cultivars were compared. A significant though moderate association (r = 0.41, P < 0.001) was detected between the COP and RFLP‐GS matrices. Spearman's rank correlation for the 142 pairs of related cultivars (COP ≥ 0.1) was somewhat higher (rS = 0.53, P < 0.001). There was a significant linear relationship between COP and RFLP‐GS for the pairs of related cultivars; however, the coefficient of determination was low (R2 = 0.25), indicating that the COP only explained a small portion of the variation observed for RFLP‐GS. COP and RFLP‐GS estimate different types of genetic resemblance; however, the moderate association may have also resulted from violations to the assumptions made when computing COP. RFLP‐GS is a more accurate estimate of true genetic resemblance among cotton cultivars. Nevertheless, the pedigree‐ and RFLP‐based dendrograms were somewhat similar, suggesting that pedigree information will continue to be useful to inexpensively identify diverse parents in a breeding program.
Grazing Evaluation of Big Bluestems Bred for Improved Forage Yield and Digestibility
Authors: Mitchell R. B. , Vogel K. P. , Klopfenstein T. J. , Anderson B. E. , Masters R. A.
Published: September 2005

Two big bluestem (Andropogon gerardii Vitman) strains (Pawnee C3 and Kaw C3) developed by three breeding cycles for increased forage yield and in vitro dry matter digestibility (IVDMD) were compared with the base populations of ‘Pawnee’ and ‘Kaw’ in a 3‐yr grazing trial. Pastures were seeded in May 1998 near Mead, NE. Experimental units were three 0.4‐ha pastures of each strain or cultivar in a randomized complete block design. Pastures were burned and fertilized with ammonium nitrate at 112 kg N ha−1 in the spring of 2000, 2001, and 2002 before grazing. Each pasture was continuously stocked with three crossbred yearling steers (Bos taurus) (380 ± 38 kg) in mid‐June 2000, 2001, and 2002 to provide a stock density of 7.5 steers ha−1 Pawnee C3 and Kaw C3 produced 16 and 7% more average daily gain (ADG), respectively, than the base populations during the 3‐yr study. Additionally, Pawnee C3 and Kaw C3 produced 14 and 5% more total body weight (BW) gain ha−1, respectively, than the base populations. Pawnee C3 ADG was 1.30 kg hd−1 and produced greater than 455 kg total BW gain ha−1 during a drought period in eastern Nebraska. Pawnee C3 pastures produced more available forage with higher IVDMD, cell soluble, cell wall digestibility, and lower lignin concentration than forages from Pawnee pastures. Kaw C3 pastures differed from Kaw pastures by producing forage with greater crude protein concentration. These results demonstrate the productivity of big bluestem pastures in the eastern Great Plains and document the positive livestock response to moderate increases in forage IVDMD. The strains bred for increased yield and IVDMD provided as much as 26% more total BW gain ha−1 at no additional cost. Pawnee C3 was released as the cultivar Bonanza and Kaw C3 was released as ‘Goldmine’.
Alfalfa and Reed Canarygrass Response to Midsummer Manure Application
Authors: Lamb JoAnn F. S. , Russelle Michael P. , Schmitt Michael A.
Published: September 2005

Perennial forages like alfalfa (Medicago sativa L.) or various perennial grasses, which are cut several times during the growing season, could provide an alternative land base and time management strategy for manure applications. Our objectives were to evaluate the response of two forage species to increasing rates of swine manure slurry applied in midsummer and to compare commercially available alfalfa cultivars for tolerance to swine manure applied during the growing season. The first experiment, hereafter referred to as the rate experiment, included four entries, two N2–fixing (UMN 3097 and ‘Agate’) and one non‐N2–fixing (Ineffective Agate) alfalfa and reed canarygrass (Phalaris arundinacea L.), grown at two locations in Minnesota. Liquid swine manure was applied at five rates (0, 23.4, 32.7, 42.1, and 93.6 kL ha−1) within 4 d after the second forage harvest in July 1998 and 1999. In the second experiment, hereafter referred to as the cultivar study, six alfalfa cultivars, Magnagraze, 5312, Rushmore, Wintergreen, Winterstar, and WL 325 HQ, were evaluated for response to manures applied at three rates (0, 37.4, and 93.6 kL ha−1) as described above. Manure slurry containing less than about 3300 kg ha−1 organic solids applied 4 d after cutting in July improved reed canarygrass yields and had no effect or slightly improved yields of normal N2–fixing alfalfa. Ineffective Agate yields improved with increasing manure rates, but insufficient N was applied to keep this entry productive. Alfalfa cultivars did not differ in yield response to manure applications. Organic solids in the manure slurries at one of the locations compromised forage yields and stand scores at the highest application rate by completely coating and smothering the plants. Results emphasized the importance of manure testing to reduce adverse effects on alfalfa and reed canarygrass yields.
RAPD and SCAR Markers Linked to an Introgressed Gene Conditioning Resistance to Peronospora tabacina D.B. Adam. in Tobacco
Authors: Milla S. R. , Levin J. S. , Lewis R. S. , Rufty R. C.
Published: September 2005

Blue mold, caused by the fungal pathogen Peronospora tabacina D.B. Adam, is one of the most important foliar diseases of tobacco (Nicotiana tabacum L.). Identification of molecular markers linked to genetic factors controlling resistance would facilitate development of resistant cultivars. Bulked segregant analysis was used to screen 1216 random amplified polymorphic DNA (RAPD) primers for their ability to reveal polymorphism between DNA bulks from susceptible doubled haploid (DH) lines and resistant DH lines possessing resistance derived from cultivar Ovens 62. Fifteen RAPD markers were tentatively identified as being linked to a major gene conditioning resistance to blue mold. These 15 markers (12 in coupling phase linkage with resistance and three in repulsion phase) were found to lie within a single linkage group of 36.6 cM and were subsequently tested on 122 DH lines derived from crosses between resistant and susceptible parents. F tests revealed statistically significant associations between resistance and each of the 15 RAPD markers. Interval mapping was used to more accurately place the quantitative trait locus (QTL) controlling resistance on the linkage map. The RAPD markers were screened on a set of 45 resistant and susceptible cultivars or breeding lines and four Nicotiana species. At variance with previous reports, marker genotypes indicated that resistance in Ovens 62 and most other blue mold resistant lines likely originated from N. debneyi Domin. Two RAPD markers flanking the most likely QTL position were converted to sequence characterized amplified region (SCAR) markers. These markers should aid in development of blue mold‐resistant tobacco cultivars worldwide.
Genetic Variation in Maize Breeding Populations with Different Numbers of Parents
Authors: Tabanao Dindo A. , Bernardo Rex
Published: September 2005

The development of breeding populations from two related inbreds restricts the amount of variability expected in the cross. Our objective was to determine if, as expected from an additive genetic model, genetic variance in maize (Zea mays L.) decreases as the number of parents of the population decreases. Eight random F2 plants derived from the same single cross were selected as parents and were selfed to form F3 families. These F3 families were intermated in a hierarchical manner to form populations with N = 1, 2, 4, or 8 parents. Testcross families were evaluated in four Minnesota environments in 2003. Marker heterozygosity at 62 simple sequence repeat loci decreased with N and had a near‐linear association with expected heterozygosity. Testcross genetic variance (VTC) generally decreased with N, although differences observed at N = 2, 4, and 8 were mostly insignificant. For grain yield, VTC was significantly higher at N = 4 than at N = 2. The VTC for grain yield at N = 4 was slightly higher than the estimate of VTC in the base population, strongly indicating a genetic variance in excess of what is predicted by an additive genetic model for a small population. Differences in testcross means were likewise inconsistent with an additive genetic model. The results imply that nonadditive gene effects in elite maize inbreds help maintain genetic variance in small populations and that using multiple parents may help sustain genetic variability in advanced cycle breeding.
Near‐Infrared Transmission and Reflectance Spectroscopy for the Determination of Dietary Fiber in Barley Cultivars
Authors: Kays Sandra E. , Shimizu Naoto , Barton Franklin E. , Ohtsubo Ken'ichi
Published: September 2005

Dietary fiber is an important quality parameter of barley (Hordeum vulgare L.) but is extremely laborious to measure. Near‐infrared (NIR) transmission and reflectance spectroscopy were investigated as rapid screening tools to evaluate the total dietary fiber content of barley cultivars. The Foss Grainspec Rice Analyzer and NIR Systems 6500 spectrometer were used to obtain transmission and reflectance spectra, respectively, of polished grains and ground barley. Total dietary fiber was determined for each cultivar by AOAC Method 991.43. Modified PLS models developed for predicting total dietary fiber, using transmission spectra (850–1048 nm) of polished grains, had a standard error of cross validation (SECV) of 10.4 (range 58–197) g kg−1 and R2 of 0.82 indicating sufficient accuracy for selecting or rejecting high dietary fiber cultivars. NIR reflectance spectroscopy (1104–2494 nm) of ground barley samples resulted in a model with SECV of 5.2 (range 58–197) g kg−1 and R2 0.96, indicating a high degree of precision in the prediction of total dietary fiber. The increased accuracy of the reflectance model may be due in part to more information available in the wavelength region used. The precision, low cost per sample and speed of measurement of the technique allow making dietary fiber selection decisions for large numbers of progeny in barley breeding programs.
Review of Corn Yield Response under Winter Cover Cropping Systems Using Meta‐Analytic Methods
Authors: Miguez Fernando E. , Bollero Germán A.
Published: September 2005

Extensive research on the use of winter cover crops (WCC) under different agricultural practices in the USA and Canada has shown both negative and positive effects on subsequent corn (Zea maysL.) yield. These contrasting results determine the need for a comprehensive quantitative review. The objective of this study was to use meta‐analytic methods to summarize and quantitatively describe the effects of WCC on corn yield based on peer‐reviewed published research. Thirty‐six studies were included in the analysis representing different regions of the USA and Canada under different agricultural practices (i.e., species, fertilization, kill date, tillage, etc.). The effect‐size used to compare studies was the response ratio, calculated as yield of corn following WCC over yield of corn following no cover. Biculture WCC increased corn yield by 21%, but there is greater variation due to the small number of studies in this group. Overall, grass WCC neither increased nor decreased corn yields and this response was not dependent on the use of N fertilizer. Legume WCC increased corn yield by 37% when no nitrogen (N) fertilizer was applied and this benefit decreased with application of N fertilizer.
Relationship between Yield Potential and Percentage Yield Suppression Caused by the Southern Root‐Knot Nematode in Cotton
Authors: Davis R. F. , May O. L.
Published: September 2005

Currently available cotton (Gossypium hirsutum L.) cultivars support significant reproduction of the southern root‐knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood], but they have not been evaluated for differing levels of yield suppression (tolerance) to this nematode. If nematode tolerant (low yield suppression) but susceptible (high nematode reproduction) cotton cultivars can be identified, they could be grown rather than intolerant cultivars to reduce yield loss. The objective of this study was to evaluate a collection of M. incognita–susceptible cotton cultivars for tolerance to parasitism by this nematode. The yield potential and percentage yield loss to M. incognita were measured in 12 genotypes in 2002 and 2003 by comparing yields in 1,3‐dichloropropene–fumigated and nonfumigated plots. The percentage yield suppression caused by M. incognita differed among cotton genotypes in both 2002 and 2003. Yield suppression ranged from 18.0 to 47.3% in 2002 and from 8.5 to 35.7% in 2003. Though significant levels of tolerance were measured in our study, 2 yr of data on percentage yield suppression show that tolerance is not consistently related to specific cultivars in the absence of nematode resistance: susceptible cultivars did not consistently express tolerance, but resistant germplasm did. Thus, it appears unlikely that cotton cultivar selection for tolerance to M. incognita can be utilized to minimize yield suppression. Regression analysis based on the 2 yr of field data revealed a relationship in which percentage yield suppression caused by M. incognita increased linearly as yield potential increased. Because the absolute and percentage losses to nematodes increase as yield potential increases, nematode management becomes increasingly important and beneficial in cotton.
Antioxidant Metabolism in Cotton Seedlings Exposed to Temperature Stress in the Field
Authors: Mahan James R. , Mauget Steven A.
Published: September 2005

Early season temperature stress adversely affects the growth and development of cotton (Gossypium hirsutum L.) seedlings. Oxidative damage resulting from temperature extremes is thought to be a cause of diminished seedling performance. Cotton (cv Fibermax 958) was planted at Lubbock, TX, in 2003 and 2004 to investigate the effect of low and high temperatures on oxidative stress and antioxidant metabolism in seedlings exposed to normal thermal variation. Early and late plantings in 2003 provided seedlings of different ages for comparisons. Malondialdehyde was slightly increased in response to low temperatures indicating some oxidative damage in the seedlings. The activities of ascorbate peroxidase and glutathione reductase were not altered in response to low or high temperatures. The glutathione pool was predominately reduced in all plantings in both years indicating sufficient reduced glutathione. It is concluded that the indicators of antioxidant metabolism varied in the seedlings but not in response to temperature variation. It is proposed that antioxidant metabolism in the seedlings was sufficient to mitigate oxidative damage with only minor alterations.