bluuebunny/crossref_metadata_2025 huggingface dataset:
Visualización Interactiva. Vectores, rectas y planos.
Authors: Mora Flores Walter , Gutiérrez Montenegro Marco
Published: September 2018

El objetivo de este libro es la visualización interactiva en 2D y en 3D. La mayoría de figuras, vienen con una liga a una aplicación, llamada usualmente “demostración” (aplicación interactiva), que se corre con Wolfram CDFPlayer(gratuito). Las “aplicaciones interactivas” son un archivo .cdf que se ejecuta con Wolfram CDFPlayer y requieren haber instalado en la computadora esta aplicación.Varias aplicaciones interactivas se usan para visualizar la dinámica de una definición o un teorema y su alcance y significado. Como es conocido, la visualización interactiva funciona bien como complemento y requiere “narrativa” por parte del profesor, para obtener buenos resultados en la enseñanza. También es deseable ejercicios de verbalización, en algunas actividades, por parte del estudiante
“A Powerful Protector of the Japanese People”: The History of the Japanese Hospital in Steveston, British Columbia, Canada, 1896–1942
Authors: Vandenberg Helen
Published: September 2018

From 1896 to 1942, a Japanese hospital operated in the village of Steveston, British Columbia, Canada. For the first 4 years, Japanese Methodist missionaries utilized a small mission building as a makeshift hospital, until a larger institution was constructed by the local Japanese Fishermen’s Association in 1900. The hospital operated until the Japanese internment, after the attack on Pearl Harbor during World War II. This study offers important commentary about the relationships between health, hospitals, and race in British Columbia during a period of increased immigration and economic upheaval. From the unique perspective of Japanese leaders, this study provides new insight about how Japanese populations negotiated hospital care, despite a context of severe racial discrimination. Japanese populations utilized Christianization, fishing expertise, and hospital work to garner more equitable access to opportunities and resources. This study demonstrates that in addition to providing medical treatment, training grounds for health-care workers, and safe refuge for the sick, hospitals played a significant role in confronting broader racialized inequities in Canada’s past.
If It Is Newsworthy, It is Ethics-Worthy: Living in the Code of Ethics for Nurses
Authors: Turner Martha
Published: September 2018

The American Nurses Association (ANA) Code of Ethics for Nurses with Interpretive Statements provides guidance for all nurses, in all roles and in all settings. Familiarity with the provisions and the interpretive statements improves our ethical awareness and our ethical competence. Current events in our communities and across the globe require a response from nurses individually and collectively. Living in the Code enanles us to form responses that are ethically sound. Advancing the profession through scholarly inquiry and establishing moral communities are other obIigations that can be achieved by living in the Code.
Duties to Self: The Nurse as a Person of Dignity and Worth
Authors: Fowler Marsha
Published: September 2018

There is a historical emphasis on duties to self, or self-regarding duties, in nursing's ethics heritage literature from the 1860s to 1965. Yet, as nursing education shifted to university settings and society and nursing moved away from a virtue-based ethics to a duty-based ethics, the emphasis on self-regarding duties was lost. In the 2001 revision of the American Nurses Association's Code of Ethics for Nurses with Interpretive Statements, that emphasis is reclaimed and restored. The 2015 version of the Code further develops and expands the ethical obligation of duties to self. The aggregate duty or principle of “duties to self” includes attention to personal health, safety, and well-being, preserving one's wholeness of character and integrity, maintaining competence, and continuing personal and professional growth.
The Impact of Feeding Method and Infant Sleep Location on Mother/Infant Sleep, Maternal Depression, and Mothers’ Well-Being
Authors: Kendall-Tackett Kathleen , Cong Zhen , Hale Thomas
Published: September 2018

Previous studies have found that exclusively breastfeeding (EBF) mothers get more sleep and report higher levels of well-being than mothers who are not EBF. We do not know whether infant sleep location influences these findings. The present analyses are from the Survey of Mothers’ Sleep and Fatigue, an online survey of 6,410 mothers from 59 countries. Feeding method and sleep location do interact and are related to babies’ and mothers’ sleep and measures of mothers’ well-being. EBF/bedsharing mothers reported more sleep, better physical health, and less depression, anger, and anxiety than non-EBF or nonbedsharing mothers. Conversely, bedsharing/non-EBF mothers had some of the worst outcomes. Bedsharing was related to positive outcomes for EBF mothers. Our findings are consistent with recommendations that non-EBF mothers avoid bedsharing.
Enhanced Demand-Side Placement Model to Meet the Needs of Transition Students
Authors: Gilbride Dennis , Stensrud Robert , Bruinekool Matt
Published: September 2018

Background:

Over the past 25 years, research has demonstrated the value of the demand-side placement model in increasing employment opportunities for people with disabilities.

Objective:

The demand-side model is focused on working with businesses (the demand-side) to create systemic change within companies to pull-in consumers, in contrast to a supply side model in which we try to push clients into employment.

Method:

This article describes an extension of the model that is focused on establishing sector-based career pipelines between transition age youth and entry-level jobs that offer opportunities for advancement along career pathways.

Findings:

A number of the components of the model described in this article have been tried in various states and localities but nowhere has this model been comprehensively implemented.

Conclusion:

The six phases of the model are outlined with a detailed description of the activities rehabilitation counselors need to perform or facilitate the system change necessary to increase employment opportunities for transition age youth.
Relasi Islam dan Negara: Studi Pemikiran Politik Islam dalam Perspektif al-Qur’an
Authors: Pulungan Jufri Suyuthi
Published: September 2018

Tulisan ini mendeskripsikan relasi Islam dan negara dalam bingkai pemikiran politik Islam dilihat dari al-Qur’an. Relasi Islam dan negara dapat dilihat dari tiga paradigma, yaitu; paradigma integralistik, sekuleristik, dan simbiotik. Kontroversi dan aktualisasi pemahaman ini disebabkan tidak adanya penjelasan secara tegas baik al-Quran maupun hadits. Sehingga dalam perjalanan sejarah umat Islam pasca Nabi Muhammad Saw sampai di abad modern ini, umat Islam menampilkan berbagai sistem dan bentuk pemerintahan, mulai dari bentuk kekhalifahan yang demokratis sampai ke bentuk yang monarkhi absolut dan oligarki. Ketika Nabi Muhammad menata kehidupan sosial, politik dan agama masyarakat Madinah sebagai negara Islam pertama itu didasarkan pada suatu hukum tertulis The Constitution of Medina (Piagam Madinah). Konstitusi Madinah sesuai dengan dasar-dasar umum yang terkandung dalam ayat-ayat al-Qur’an. Dalam konteks negara modern, Indonesia dengan Pancasila-nya merupakan rumusan negara modern, seperti termaktub dalam Mukaddimah UUD 1945 merupakan platform negara-bangsa (nation state) Indonesia yang pluralistik dan dalam batas-batas tertentu memiliki “kesamaan” dengan  Piagam Madinah. Meskipun al-Qur’an tidak menetapkan tentang sistem dan bentuk pemerintahan serta bagaimana mewujudkannya. Tapi, al-Qur’an menyebut adanya ide atau prinsip dasar pembentukan negara dan adanya kepala negara. Di sini, umat Islam diberi kebebasan untuk memilih sesuai dengn tuntutan kehidupan mereka yang sangat dipengaruhi perkembangan zaman. Demikian juga dalam kaitannya dengan term masyarakat madani juga tidak ditemukan dalam al-Qur’an. Namun, ada dua kata kunci yang bisa mendekati konsep masyarakat madani, yakni term ummah dan term madinah. Kedua term ini, menjadi nilai dasar dan nilai-nilai instrumental bagi terbentuknya masyarakat madani, kata ummah, bisa dirangkaikan dengan sifat dan kualitas tertentu, seperti ummah wasathan, khairu ummah dan ummah muqtashidah yang merupakan pranata sosial utama yang dibangun oleh Nabi Saw segera setelah hijrah ke Madinah. Konsep dan kegiatan politik sistem pemerintahan dalam Islam pada prinsipnya bertumpu pada keadilan. Keadilan yang merupakan mahkota hukum menjadi sebuah keniscayaan untuk senantiasa ditegakkan oleh pemerintah. Pemerintahan harus dibangun berdasarkan asas-asas normatif untuk mengatur negara yang berlandasan pada asas amanat, asas keadilan (keselarasan), asas ketaatan (disiplin) dan sunnah. Asas sunnah menghendaki agar hukum-hukum perundang-undangan dan kebijakan politik ditetapkan melalui musyawarah di antara mereka yang berhak Sehingga dalam menentukan kebijakan juga berfungsi sebagai check and balance pemerintah.
Estresse no cotidiano de graduandos de enfermagem de um instituto federal de ensino
Authors: Santana Leni De Lima , Beljaki Walkiria Denipotti , Gobatto Mariangela , Raeffner Rafael , Antonacci Milena Hohmann , Buzzi Jane Aparecida Pereira
Published: September 2018

Objetivos: identificar os n�veis de estresse e caracterizar a sintomatologia entre discentes de gradua��o em enfermagem de um

Instituto Federal de Ensino. M�todo: Estudo descritivo transversal cuja coleta de dados ocorreu por meio da aplica��o do

Invent�rio de Sintomas de Estresse de Lipp e de um question�rio sociodemogr�fico elaborado pelos pesquisadores. Os resultados

foram analisados por meio de estat�stica descritiva. Resultados: A an�lise evidenciou que 73,7% dos alunos apresentavam algum

n�vel de estresse, com destaque para sintomas na fase de resist�ncia. Os sintomas predominaram entre acad�micos

autodeclarados pardos (80,0%), provenientes de escolas p�blicas (74,3%), n�o cotistas (74,1%), repetentes (83,3%) e entre

acad�micos que n�o trabalham formalmente (73,8%). O desfecho foi associado �s vari�veis independentes: tipo de cota (p =

0,019), per�odo letivo (p = 0,003) e uso de medicamentos (p = 0,04). Quanto � sintomatologia apresentada, predominaram os

sintomas de car�ter psicol�gico, apresentados por 50% da amostra. Conclus�o: todos os per�odos do curso avaliado apresentaram

estresse em n�vel variado o que merece a aten��o por parte da institui��o e do corpo docente no sentido de rever as metodologias

adotadas, bem como propor a��es que visem o bem-estar e o desempenho acad�mico.
Sa�de da crian�a na aten��o prim�ria: evolu��o das pol�ticas brasileiras e a atua��o do enfermeiro
Authors: Branquinho Isabella Duarte , Lanza Fernanda Moura
Published: September 2018

Objetivos: Descrever o processo de constru��o hist�rica das pol�ticas de aten��o � sa�de da crian�a no Brasil, a participa��o da

enfermagem nesse processo e os avan�os e desafios atuais para a aten��o prim�ria � sa�de. M�todo: Trata-se de um artigo de

reflex�o te�rica. Resultados: A aten��o � sa�de da crian�a no Brasil passou por um extenso processo de evolu��o e qualifica��o no

�mbito das pol�ticas p�blicas, o que resultou em avan�os na redu��o da mortalidade infantil e da desnutri��o e na amplia��o da

cobertura vacinal. Os atuais desafios � a mortalidade neonatal e a obesidade � est�o elencados na atual diretriz program�tica

brasileira e tamb�m nos objetivos do Desenvolvimento Sustent�vel. O enfermeiro destacou-se como um profissional com

participa��o efetiva e fundamental na aten��o � sa�de da crian�a, mesmo antes da consolida��o do SUS e da promulga��o da lei

do exerc�cio profissional. Conclus�o: Para superar as lacunas entre as diretrizes program�ticas e a capilaridade dessas pol�ticas na

realidade dos servi�os de sa�de, torna-se necess�ria a consolida��o da presen�a e extens�o dos atributos da APS nos servi�os de

sa�de brasileiros.
Twenty‐Four Cycles of Mass Selection for Prolificacy in the Golden Glow Maize Population
Authors: de Leon N. , Coors J. G.
Published: September 2018

Maize (Zea mays L.) has the potential to produce an ear primordium at several nodes, and selection for increased prolificacy often increases grain yield. We have previously demonstrated the effectiveness of mass selection for increasing the number of active ear shoots in the ‘Golden Glow’ maize population. The objective of our research was to evaluate associated changes in ear and plant morphology after 24 cycles of mass selection for prolificacy in Golden Glow. Cycles 0, 6, 12, 18, 23, and 24 were grown in 1997 at two locations (Madison and Arlington, WI) at two planting densities (15 070 and 73 197 plants ha−1). At the lower planting density, the mean number of ears per plant increased from 1.61 at C0 to 4.93 at C24, and the response rate increased over the more recent cycles, mainly from C18 to C24. At C24, tiller number has increased, and lateral branches (terminating in ears) were located at approximately one node higher and two nodes lower on the main stalk compared with the original population. Total node number on the main stalk increased, and the internode length decreased over the 24 cycles, but the opposite occurred for lateral branches. At the lower planting density, ear diameter, ear length, and kernel size decreased by 0.03, 0.10, and 0.01 cm cycle−1, respectively, but total number of kernels per plant and dry kernel weight per plant increased significantly at a rate of 36.69 kernels cycle−1 and 5.60 g cycle−1 over the 24 cycles. Similar trends, but of lesser magnitude, were observed at the higher planting density. The changes in plant morphology observed across cycles of selection for prolificacy represent a general derepression of axillary meristematic growth in both main stalks and lateral branches.
A Novel Gene ef1‐h Conferring an Extremely Long Basic Vegetative Growth Period in Rice
Authors: Nishida Hidetaka , Inoue Hiromo , Okumoto Yutaka , Tanisaka Takatoshi
Published: September 2018

A late‐heading mutant line, HS169, which was induced by gamma‐ray irradiation to seeds of the japonica rice (Oryza sativa L.) cultivar Gimbozu, has an extremely long basic vegetative growth (BVG) period. A genetic analysis using the F2 population from the cross HS169 × Gimbozu showed that the late heading of HS169 is governed by a recessive mutant gene. The subsequent analysis of heading responses of HS169, Gimbozu, and six heading‐time tester lines to five photoperiods (10, 13, 14, 15, and 16 h) revealed that the mutant gene confers an extremely long BVG period by itself. A recessive allele, ef1, at the heading‐time locus Ef1 has been considered to confer an extremely long BVG period, but experimental results showed that the effect of ef1 is modified by the allelic constitution at the photoperiod sensitivity locus Se1 The allele ef1 increases the BVG period markedly only when coexisting with the nonfunctional allele Se1‐e at the Se1 locus. As a result of allelism test and subsequent trisomic analysis, the mutant gene was found to be a nonfunctional allele at the Ef1 locus on chromosome 10. We designated this mutant gene ef1‐h On the basis of the results, causal genetic pathways to flowering in rice and the significance of ef1‐h in recent rice breeding in the low latitudes were discussed.
Resistance to Aspergillus Ear Rot and Aflatoxin Accumulation in Maize F1 Hybrids
Authors: Naidoo G. , Forbes A. M. , Paul C. , White D. G. , Rocheford T. R.
Published: September 2018

Unacceptable levels of contamination by aflatoxin, a carcinogenic toxin, produced by Aspergillus flavus Link:Fr can halt the sale and shipment of maize (Zea mays L.) grain. Our objectives were to: (i) determine the relative resistance to A. flavus and aflatoxin accumulation in F1 hybrids produced by crossing promising resistant maize inbreds, regardless of heterotic pattern; (ii) investigate the genetic basis of resistance for this subset of inbreds through diallel analysis; and (iii) determine which inbreds are the most promising sources of resistance for molecular marker mapping and breeding programs. Two historically important inbreds and six inbreds tentatively associated with reduced ear rot and inhibition of aflatoxin production were crossed in all combinations. The resulting F1 hybrids were evaluated for two years. Ears were inoculated 20 to 24 d after midsilk by a pinboard method and a mixture of conidia of Aspergillus flavus Link:Fr. isolates. Individual ears from each plot were rated by scoring the percent visible rot in the inoculated area. Aflatoxin B1 levels in harvested ears were determined by an indirect competitive ELISA. The highest level of resistance for ear rot and aflatoxin accumulation was detected for resistant inbred × resistant inbred F1 hybrids, but they were not significantly different from many resistant inbred × historically important inbred F1 hybrids. Diallel analysis indicated general combining ability (GCA) effects for ear rot and aflatoxin levels were highly significant among hybrids overall, and for the inbreds Tex6 and Oh516. The results indicate that Tex6 and Oh516 are promising resistance sources for molecular marker mapping and breeding programs in diverse genetic backgrounds.
Identifying Inbred Lines Capable of Improving Ear and Stover Yield and Quality of Superior Silage Maize Hybrids
Authors: Bertoia Luis M. , Burak Ruggero , Torrecillas Marcelo
Published: September 2018

Maize (Zea mays L.) is an excellent feed, whether fresh, chopped, or ensiled. Silage maize hybrids have been developed for temperate‐cold regions of Europe and North America, but limited research has been done to develop silage hybrids for temperate and warm‐temperate regions. This study was conducted to identify inbred lines that could be used to enhance the stover and ear fractions of existing hybrids for warm‐temperate areas. Forty‐five single‐cross hybrids were developed from 10 inbred lines and evaluated in six environments. Ten inbred lines were evaluated for potential to improve the best hybrids by Dudley's and Metz's methodologies. Hybrids differed significantly (P < 0.01) for ear (EY), stover (SY), and whole‐plant dry matter yield (WY), in vitro digestibility of whole‐plant dry matter (iDW), and whole‐plant digestible dry matter yield (WDY), differences among hybrids were not significant for in vitro digestibility of ear (iDE) and stover (iDS). Four outstanding hybrids were selected as target hybrids for improvement on the basis of YSi (Kang's Yield‐Stability Statistic) of mean WDY and their stability across environments. Inbred lines that were able to increase SY were not the same ones that would increase EY. Inbred PR4 had outstanding potential to improve the SY of any hybrid. Inbred B84 had greatest potential to enhance EY. Inbred lines showed differential capacity to generate improvement according to the fractions that were evaluated. Finally, inbred lines from the North American Corn Belt did not demonstrate potential for enhancing SY when they were compared with local flint inbred lines.
Selecting Increased Seed Density to Increase Indirectly Soybean Seed Protein Concentration
Authors: Li Hongxia , Burton Joseph W.
Published: September 2018

Because soybean [Glycine max (L.) Merr.] is the world's most important source of high quality vegetable protein, development of high yielding genotypes with increased seed protein concentration is a major soybean breeding objective. A major impediment to this objective is the often observed negative correlation between yield and protein. Seed density is a component of grain yield that is correlated positively with seed protein concentration. If genotypic correlations between seed density and yield are low, selection for increased density could provide an efficient way to improve protein concentration without affecting seed yield. The objective of this study was to investigate direct and correlated responses to selection on density of seeds sampled from male‐sterile plants in three different random‐mating populations. Seed density was determined for 192 male‐sterile plants in each population. In each population, 15 plants with the highest and 15 plants with lowest seed density were selected. Seeds of each selection were increased in the winter and tested the following summer at three locations in North Carolina with two replications per location. In those tests, the previously selected high and low density groups were not significantly different in seed density, seed weight, yield, or concentrations of protein and oil. Thus, single plant selection for seed density was ineffective for increasing seed density or seed protein concentration. An alternative selection method is proposed in which the selection unit is a selfed half‐sib or S1 family. Desired gains selection indices for increased density and seed weight may increase both protein and yield in all three populations. This selection system has appeal because measurement of seed density and seed weight is relatively inexpensive, requiring less economic and land resources than actual measurement of yield and protein. It is recommended as a low‐cost way to improve initially unadapted populations.
Diurnal and Seasonal Photosynthesis in Two Asparagus Cultivars with Contrasting Yield
Authors: Guo Jianmin , Jermyn William A. , Turnbull Matthew H.
Published: September 2018

To investigate physiological characters underpinning spear yield in asparagus (Asparagus officinalis L.), diurnal and seasonal changes in photosynthetic parameters were measured under field conditions in two cultivars with contrasting yield. Seasonal patterns in photosynthetic parameters were strongly dependent on cladophyll developmental stage in both cultivars. The greatest photosynthetic rates of 8.94 ± 0.54 μmol m−2 s−1 for the high‐yielding cultivar (ASP‐69) and 6.50 ± 0.38 μmol m−2 s−1 for the low‐yielding cultivar (ASP‐03) were observed in fully expanded cladophyll tissue measured in mid‐summer (February) when both photon flux density (PFD) and temperature were at a maximum. A significant decline in net photosynthetic rate (A) was measured in April, when plants experienced colder night temperatures and shorter day lengths. A close correlation between A and stomatal conductance (gs) (r = 0.84) was observed. Timing of cladophyll initiation and duration did not appear to be significant factors contributing to cultivar difference in photosynthesis. Variation in photosynthetic capacity between the two cultivars was related to significant differences in cladophyll thickness and specific leaf weight (SLW). The results substantiate the conclusion that both metabolic and anatomical factors play significant roles in determining differences in photosynthetic capacity between the two asparagus cultivars studied.
Influence of Trinexapac‐Ethyl on Respiration of Isolated Wheat Mitochondria
Authors: Heckman Neil L. , Elthon Thomas E. , Horst Garald L. , Gaussoin Roch E.
Published: September 2018

The plant growth regulators (PGRs) 2,4‐D [(2,4‐dichlorophenoxy) acetic acid] and malic hydrazide (1,2‐dyhydro‐3,6‐pyridazinedione) have been shown to reduce plant respiration. The effect of other PGRs such as trinexapac‐ethyl [(4‐cyclopropyl‐α‐hydroxy‐methylene)‐3,5‐dioxocyclohexanecarboxylic acid methyl ester] on respiration is unknown. Experiments were conducted to evaluate the effects of trinexapac‐ethyl and 2‐oxoglutarate on the respiration of mitochondria isolated from wheat (Triticum aestivum ‘Arapahoe’) seedlings. Trinexapac‐ethyl applied at increasing concentrations inhibited nicotinamide adenine dinucleotide (NADH)‐dependent O uptake, while 2‐oxoglutarate had no significant effect. This is different than other reports that trinexapac‐ethyl may compete with 2‐oxoglutarate for binding sites. Different regions of the mitochondria were tested to determine the site of inhibition caused by trinexapac‐ethyl. Nicotinamide adenine dinucleotide dehydrogenase activity, duroquinol‐dependent O uptake, and cytochrome bc1 activity were all reduced by ≈30% in the presence of 10 mM trinexapac‐ethyl. Succinate‐dependent O uptake, alternative oxidase, and cytochrome oxidase were not reduced by any trinexapac‐ethyl concentration. This revealed possible interference of trinexapac‐ethyl with ubiquinone binding sites. The reduced form of trinexapac‐ethyl was observed to inhibit the electron transport chain greater than the oxidized form. Reduction in respiration from trinexapac‐ethyl may result in greater stress tolerance in treated plants.
Losses in Wheat Due to Waterlogging
Authors: Collaku A. , Harrison S. A.
Published: September 2018

Waterlogging stress is one of the limiting factors influencing wheat (Triticum aestivum L.) production, especially in the lower Mississippi valley. A rain‐shelter experiment was designed to evaluate the trend response of nine wheat genotypes to four levels of waterlogging treatment: 0, 10, 20, and 30 d of flooding. Genotypes planted in polyvinilchloride (PVC) containers 25 cm long by 10 cm in diameter were waterlogged in plastic tanks under controlled rain conditions. Results indicated significant linear responses for kernels per head and tillers per plant, significant linear and quadratic responses for yield and chlorophyll content, and significant linear and cubic responses for plant height. The linear trend was the most important component, explaining from 92 to 99% of the variability due to waterlogging. Linear prediction equations were obtained to describe the relationship between different traits and waterlogging stress. Losses in yield and yield components were evaluated in a field experiment with 15 genotypes under control and waterlogging treatment. Average yield losses of 44% were mainly caused by a decrease in tiller number and kernels per head. Under waterlogging treatment, tiller number and kernels per head were reduced by 41 and 20%, respectively. Screening of wheat genotypes revealed the potential for waterlogging tolerance in breeding material and identified tolerant cultivars useful for waterlogged environments. ‘Terral LA 422’, ‘Shelby’, and ‘Pioneer 2691’ were the most adapted genotypes for waterlogging treatments. Because of a significant interaction with waterlogging treatment, some of the high‐yielding genotypes under non‐flooded conditions such as ‘Coker 9663’ and ‘FFR 502W’ showed low tolerance to waterlogging. The results provided information on the methods quantifying losses from waterlogging and identified selection criteria for waterlogging tolerance in wheat.
Seed Vigor, Soilborne Pathogens, Preemergent Growth, and Soybean Seedling Emergence
Authors: Hamman Brigitte , Egli D. B. , Koning Gwen
Published: September 2018

Emergence of soybean [Glycine max (L.) Merr.] seedlings in the field is frequently less than predicted by standard germination, but the causes of this emergence failure are not well understood. This study explored the influence of soil pathogens and seed vigor on soybean seedling preemergent growth and emergence. Seed from six seedlots, representing a range in seed vigor, were planted as pregerminated and as dry seed into sterile and pathogen‐infested soil maintained at a constant soil water potential (−0.005 MPa). Final emergence (FE) and emergence rates from two planting depths (25 and 60 mm) were recorded under ambient greenhouse conditions. Once the FE stage had been reached, nonemerged seedlings were exhumed, and classified as stunted, abnormal, or dead. The FE of the high‐ and medium‐vigor seedlots was always higher than the low‐vigor seedlots, and the advantage was greatest under stressful conditions (deep planting, nonsterile soil). The FE was always lower in nonsterile than sterile soil. Seedlings emerged more slowly from deep plantings and when pathogens were present, and FE decreased as emergence was delayed in nonsterile soil. This relationship became more pronounced with low vigor seed. Planting pregerminated seeds always resulted in higher FE than dry seeds, but it did not eliminate emergence failure. Abnormal seedlings accounted for most of the emergence failure in sterile soil, but the lack of germination or of growth immediately after germination was also important in nonsterile soil. Lack of germination alone therefore does not account for lack of emergence; postgerminative, preemergent growth may be more important.
Application of Canonical Discriminant Analysis for the Assessment of Genetic Variation in Tall Fescue
Authors: Vaylay Ravi , van Santen Edzard
Published: September 2018

Tall fescue pastures are perennial in habit and are continually exposed to intensive natural selective forces. Therefore, the genetic composition of tall fescue cultivars changes with time and the selection is cumulative. The objective of this study was to investigate the genetic diversity of tall fescue cultivars and age groups within cultivars in response to natural selective forces using a multivariate statistical method, canonical discriminant analysis. Ungrazed survivors from four cultivars (GA‐5 EF, GA‐5 EI, Johnstone, and KY‐31) were collected randomly from four 1‐yr‐old paddocks. These paddocks were then grazed at 2.50, 3.75, 5.00, and 6.25 Angus yearling steers ha−1 for 2 yr, and grazed survivors were collected in a similar fashion as that of ungrazed survivors. The ungrazed and grazed groups were compared in a 2‐yr study along with plants grown directly from the original seed lots. Significant genetic diversity was noticed among these four tall fescue cultivars and clearly depicted the relationship of cultivars by ancestry and endophyte status. Significant genetic diversity between GA‐5 EF and GA‐5 EI indicated that the removal of endophyte resulted in a different cultivar with altered morphological and agronomic characteristics. Significant genetic diversity was observed among the age groups in GA‐5 EF, GA‐5 EI, and Johnstone. The age groups of KY‐31 were stable in terms of genetic variation. These results indicated that changes in genetic variation occurred in a short period of time, that is, 3‐yr old paddocks of GA‐5 EF, GA‐5 EI, and Johnstone.
Genetic Mapping of Agronomic Traits in Common Bean
Authors: Tar'an Bunyamin , Michaels Thomas E. , Pauls K. Peter
Published: September 2018

SBreeding effort to improve yield and other quantitative traits in common bean (Phaseolus vulgaris L.) has proven to be difficult. The use of molecular markers will improve our understanding of the genetic factors conditioning these traits and is expected to assist in the selection of superior genotypes. This study was conducted to identify genetic loci associated with 14 quantitative traits responsible for seed yield, yield components, and plant architecture traits in common bean. A population of 142 F2:4 lines that was developed from a cross between OAC Seaforth and OAC 95‐4, was evaluated at two locations in Canada in 1998. The lines were assayed for random amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP), simple sequence repeat (SSR), and amplified fragment length polymorphism (AFLP) markers. One hundred fourteen markers were assigned to 12 linkage groups. Growth habit and resistance to common bacterial blight [CBB, caused by Xanthomonas axonopodis pv. phaseoli (Smith) Vauterin, Hoste, Kosters & Swings = syn. X. campestris pv. phaseoli (Smith) Dye] were each mapped as single major genes on linkage groups G11 and G5, respectively. An alignment of the current map with the previous linkage map developed at the University of Florida and the core linkage map of bean was produced from 30 RFLP loci. Twenty quantitative trait loci (QTL) were identified for the 14 traits that were analyzed. The number of QTL identified per trait ranged from one to three. A multiple QTL model for each trait showed that these genomic regions accounted for 11.3 to 43.1% of the total phenotypic variation for the traits. Five of the twenty QTL were detected at both locations. The strengths of QTL effects for a given trait appeared to be slightly different among locations, but the positions of QTL on the map were stable across locations.
A PCR Assay for Rapid Discrimination of Sterile Cytoplasm Types in Maize
Authors: Liu Zhiyong , Peter Stefan O. , Long Muhua , Weingartner Urs , Stamp Peter , Kaeser Olivier
Published: September 2018

A single‐seed, multiplex polymerase chain reaction (PCR) protocol is presented to distinguish the three major types of cytoplasmic male sterility (CMS‐T, ‐C, and ‐S) in maize (Zea mays L.). Three pairs of PCR primers were designed, corresponding to the chimeric regions of mitochondrial DNA sequences specific for the three types of CMS cytoplasm. The specificity of these primers was tested by means of the inbred line B37 with male‐sterile (T, C, and S) and normal (N) cytoplasm as reference material. Subsequently, a single‐seed PCR assay was developed for the determination of cytoplasm types in a single reaction and applied to a wide range of inbred lines with normal and sterile cytoplasm (T, C, and S) and with predominantly identified subtypes of the major sterile cytoplasm types. Our protocol proved to be a rapid, inexpensive, and reliable procedure for the molecular classification of male sterile maize cytoplasm to the three major categories T, C, and S.
Quantitative Trait Loci for First‐ and Second‐Generation European Corn Borer Resistance Derived from the Maize Inbred Mo47
Authors: Jampatong Chaba , McMullen Michael D. , Barry B. Dean , Darrah Larry L. , Byrne Patrick F. , Kross Heike
Published: September 2018

European corn borer (ECB), Ostrinia nubilalis (Hübner), family Crambidae, order Lepidoptera, is a serious insect pest of maize (Zea mays L.) in the USA. Understanding the genetic basis for ECB resistance should increase the efficiency of breeding insect‐resistant germplasm. The objectives of this study were to determine the number, genomic positions, and genetic effects of quantitative trait loci (QTL) conferring resistance to leaf feeding damage cause by first‐generation ECB (1ECB, defined as the trait of leaf feeding damage) and stalk tunneling caused by second‐generation ECB (2ECB, defined as the trait of stalk tunnel damage). The study included 244 F2:3 families derived from the cross of B73Ht (susceptible) × Mo47 (resistant). Inbred Mo47 represented a novel source of ECB resistance containing 50% tropical germplasm. The QTL analyses for three individual environments and combined across environments were performed by composite interval mapping using QTL Cartographer. Nine QTLs were identified for 1ECB on chromosomes 1 (three QTLs), 2, 4 (two QTLs), 5, 6, and 8, on the basis of data combined across environments. Seven QTLs for 2ECB were found on chromosomes 2, 5 (two QTLs), 6 (two QTLs), 8, and 9. Several of the QTLs detected are located in genomic regions reported for resistance to other stem borer pests of maize. Inconsistency of QTLs across environments complicates use of Mo47 for marker‐assisted selection of ECB resistance.
Yield and Molecular Diversity of Soybean Lines Derived from Crosses of Northern and Southern Elite Parents
Authors: Cornelious B. K. , Sneller C. H.
Published: September 2018

Genetic diversity is low in southern United States elite soybean [Glycine max (L.) Merr.] cultivars. Multiple sources of diversity will be required to effectively diversify this gene pool. The objective in this study was to evaluate the genetic diversity and yield of familiess derived from crosses between northern elite (NE) by southern elite (SE) parents. Lines were derived from 10 crosses of NE × SE parents. Molecular markers were used to estimate genetic distance between each line and its SE parent. Yield and agronomic traits were measured in field trials from 1997 to 1999 in six of the crosses. The association of diversity with line yield, expressed relative to yield of the SE parent was determined with regression. On average, the use of NE parents reduced yield, relative to using other SE parents. Some crosses and NE parents were better than others and produced families with yield that exceeded that of their SE parent, indicating that some genes from the NE parents were superior to the genes in the SE parent. At least one line with yield either superior or similar to their SE parent was found in each cross. The finding of positive transgressive segregants in some crosses and the results of the regression analyses indicate that most of the NE parents posses some yield genes that are likely to be superior to those of the SE parents. Our approach to selecting for diversity and yield may be applicable to large introgression programs where diversity from many sources is desired.
Highly Efficient Doubled‐Haploid Production in Wheat (Triticum aestivum L.) via Induced Microspore Embryogenesis
Authors: Liu Weiguo , Zheng Ming Y. , Polle Enrique A. , Konzak Calvin F.
Published: September 2018

An efficient doubled‐haploid production technology that induces homozygosity can greatly reduce the time and cost of cultivar development. Low efficiency of doubled‐haploid production previously has limited exploitation of this method for crop improvement. This study aimed to develop a more efficient and effective isolated microspore culture system for generating doubled‐haploid wheat (Triticum aestivum L.) plants. We report here the development and testing of a new chemical formulation for its efficiency to induce microspore embryogenesis, and the development of a system for double haploid production, in which the induction of embryogenesis in microspores was followed by isolating embryogenic microspores, and culturing them under optimized growth conditions to produce high embryoid yields. Up to 50% of the total treated microspores in the whole spike were converted from their preprogrammed gametophytic to a sporophytic pathway by a chemical inducer formulation consisting of 0.1 g L−1 of 2‐hydroxynicotinic acid, 10−6 mol L−1 2,4‐dichlorophenoxyacetic acid, and 10−6 mol L−1 6‐benzylaminopurine. The isolated embryogenic microspores were cocultivated with live wheat ovaries in a liquid NPB 99 media with an osmolality of about 300 mOsmol kg−1 H2O, resulting in the regeneration of 50 to 5500 green plants per single spike of eight wheat genotypes. The high efficiency and simplicity make the system practical for biological research and for accelerating cultivar development in wheat breeding programs.
Comparison of Three Procedures for Early Generation Testing of Soybean
Authors: St. Martin Steven K. , Geraldi Isaias O.
Published: September 2018

Early generation testing as a breeding procedure for autogamous crops consists of testing heterogeneous families, followed by selection of homozygous lines from superior families. Although early generation testing has been compared with other breeding methods, there have been few comparisons of different early generation testing procedures. Our objective was to assess the effectiveness of testing F1‐, F2‐, and F3‐derived families in soybean [Glycine max (L.) Merr.]. We applied the three procedures to two soybean populations from 1986 to 1993. Selected lines (F3‐, F4‐, and F5‐derived, respectively) were obtained by applying each testing method to each population. Divided into maturity classes, these selected lines were compared with unselected lines of the same generation, population, and maturity to determine genetic gain. The three early generation treatments produced similar genetic gains in seed yield, averaging approximately 4%. Selection of F1‐derived families for yield increased plant height and lodging, but the other two selection procedures were satisfactory in this respect. To maximize genetic gain for yield while avoiding undesirable changes in lodging in an early‐generation testing program, we recommend testing F2‐derived families, unless off‐season nurseries permit development of F3‐derived families without further loss of time.
Forage Yield Heterosis in Alfalfa
Authors: Riday Heathcliffe , Brummer E. Charles
Published: September 2018

Increasing forage yields remains a top priority of most alfalfa (Medicago sativa L.) breeding programs, but yield trends suggest yield has stagnated over the past two decades. Little effort has been invested into capturing heterosis in alfalfa, but semihybrid breeding systems are a possible solutions to overcome forage yield stagnation. Development of alfalfa semihybrids will require identification of heterotic groups. Studies of crosses between dormant M. sativa ssp. sativa and M. sativa ssp. falcata suggest a heterotic pattern exists between the two subspecies. The objective of this study was to measure heterosis in elite sativa × falcata crosses (SFC) in relation to elite sativa × sativa crosses (SSC) and falcata × falcata crosses (FFC). Nine elite sativa clones and five falcata clones were crossed in a diallel mating design. Progeny were space planted in 1998 at Ames and Nashua, IA, and harvested for forage yield twice in 1998 and three times in 1999. A definite sativa–falcata heterotic pattern was observed. Sativa–falcata heterosis was observed at the subspecies, halfsib, and individual cross level calculated using subspecies comparisons, halfsib heterosis analysis, and combining ability analysis. On average, intersubspecific crosses yielded 18% more than the average of intrasubspecific crosses. The sativa–falcata heterotic pattern is a potentially useful resource in alfalfa breeding programs.
Alfalfa Root Carbohydrates and Regrowth Potential in Response to Fall Harvests
Authors: Dhont Catherine , Castonguay Yves , Nadeau Paul , Bélanger Gilles , Chalifour François‐P.
Published: September 2018

The adverse effect of harvesting alfalfa (Medicago sativa L.) during a critical fall rest period on the persistence and the following spring regrowth has been historically attributed to a reduction in the levels of root organic reserves, especially total nonstructural carbohydrates (TNC). Recent reports also pointed out the role of specific carbon (C) reserve components in winter survival. This study assessed the effect of the timing of a fall harvest on the regrowth potential in relation to quantitative changes in C reserves in alfalfa roots during fall and winter. The experiment was conducted under simulated winter conditions in an unheated greenhouse with two alfalfa cultivars (AC Caribou and WL 225) subjected to four fall harvest treatments: two summer harvests (control) and a third harvest taken in the fall at 400, 500, or 600 growing degree days (GDD) after the second harvest. Shoot regrowth was reduced by a fall harvest, especially when plants were harvested at 400 or 500 GDD. Root soluble sugar concentrations (sucrose, raffinose, and stachyose) measured during the overwintering period were higher in plants harvested in the fall than in those harvested only twice; these concentrations were also higher in the more hardy cultivar AC Caribou compared with WL 225. A fall harvest did not consistently affect root TNC concentrations, but decreased markedly the total amount of TNC in roots, especially in plants harvested at 400 GDD. In both cultivars, shoot regrowth in spring was correlated positively to the total amounts of root starch (r = 0.54 and 0.61) and TNC (r = 0.55 and 0.56), but not correlated to their concentrations. Our results suggest that the total amount of C organic reserves in alfalfa roots rather than their concentrations can be determinant factors of shoot regrowth.
Grain and Dry Matter Yields and Partitioning of Assimilates in Japonica/Indica Hybrid Rice
Authors: Yang Jianchang , Peng Shaobing , Zhang Zujian , Wang Zhiqin , Visperas Romeo M. , Zhu Qingsen
Published: September 2018

Poor grain filling is a major constraint in utilizing the heterosis of japonica/indica hybrid rice (Oryza sativa L.). The objective of this study was to investigate potential causes of poor grain filling of japonica/indica hybrids (J/IHs) by examining the source‐sink relations in 36 J/IHs. Thirty‐six J/IHs and their parents and two intervarietal hybrids (IVHs) were grown at the Yangzhou University farm during the 1998, 1999, and 2000 rice growing seasons. Growth analyses were performed at heading and during grain filling period, and yield and yield components were determined at maturity. Results showed that J/IHs had 18.9% greater spikelet number per square meter than the two IVHs because of the difference in spikelet number per panicle, but grain yields of the two kinds of hybrids did not differ significantly as a result of low spikelet filling percentage in J/IHs. Above‐ground dry matter accumulation of J/IHs was 73.8% greater than that of IVHs during the grain filling period. The above‐ground dry matter per spikelet of the J/IHs was 12.7 and 4.1% higher than that of their parents and IVHs, respectively, indicating that source limitation was not the cause of poor grain filling of J/IHs. Translocation of assimilates and remobilization of stored assimilates from the straw to the grains during the grain filling period in J/IHs was about 64%, which was significantly less than that of IVHs. At maturity, only 44.1% of 14C fed to the flag leaves of J/IHs was partitioned into grains and the rest remained in stems and leaves. Poor translocation and partitioning of assimilates to the grain of J/IHs resulted in low harvest index. The results suggest that poor transport of assimilates to grains account for poor grain filling of J/IHs.
Cultivar Composition and Spatial Patterns in Kentucky Bluegrass Blends
Authors: Lickfeldt Darin W. , Voigt Thomas B. , Hamblin Andrew M.
Published: September 2018

Turfgrass managers make informed decisions when choosing cultivars, but they do not know the cultivar composition or spatial patterns of a blended Kentucky bluegrass (Poa pratensis L.) stand after establishment. This study was conducted to determine the cultivar composition of blends and determine whether cultivars form distinct clumps or a random distribution. Percentages of ‘Blacksburg’, ‘Midnight’, and ‘Unique’ in blends were determined using random amplified polymorphic DNA markers. The two different locations were a fairway (Aspen Ridge Golf Course, Bourbonnais, IL) and a rough (Alpine Hills Golf Course, Rockford, IL). Indices of dispersion were used to determine spatial patterns. Even though the two stands had different management strategies and were 157 km apart, the two blends had similar cultivar compositions in October 2000. The fairway was comprised of 14% Blacksburg, 46% Midnight, and 40% (w/w) Unique 37 mo after seeding, while the rough composition was 14% Blacksburg, 47% Midnight, and 39% (w/w) Unique 15 mo after seeding. Chi‐square analyses indicated with more than 99% confidence that the cultivar compositions were different than the intended planting. Comparing expected (first sampling) with observed (second sampling) values at both sites, chi‐square analyses determined that none of the mean percentages for the three cultivars had changed from the first sampling date to the second at either location. Since the two stands were not the same age, they may have achieved an equilibrated composition dictated by the competitve advantages of the component cultivars. Indices of dispersion determined the cultivars were distributed randomly rather than clumped. This study suggests management and location do not dictate the composition of a blend. Rather, the competitive advantages of the cultivars in the blend will determine composition.