Genetic Diversity of Wild Oat (Avena fatua)Populations from China and the United States

Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Runzhi Li ◽  
Shiwen Wang ◽  
Liusheng Duan ◽  
Zhaohu Li ◽  
Michael J. Christoffers ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Gene Diversity ◽  
Genetic Relationships ◽  
The United States ◽  
Mantel Test ◽  
Wild Oat ◽  
Chinese Populations ◽  
Nei's Distance ◽  
The Impact

Weed genetic diversity is important for understanding the ability of weeds to adapt to different environments and the impact of herbicide selection on weed populations. Genetic diversity within and among six wild oat populations in China varying in herbicide selection pressure and one population in North Dakota were surveyed using 64 polymorphic alleles resulting from 25 microsatellite loci. Mean Nei's gene diversity (h) for six wild oat populations from China was between 0.17 and 0.21, and total diversity (HT) was 0.23. A greater proportion of this diversity, however, was within (Hs= 0.19) rather than among (Gst= 0.15) populations. For the wild oat population from the United States,h= 0.24 andHT= 0.24 were comparable to the values for the six populations from China. Cluster analysis divided the seven populations into two groups, where one group was the United States population and the other group included the six Chinese populations. The genetic relationships among six populations from China were weakly correlated with their geographic distribution (r= 0.22) using the Mantel test. Minimal difference in gene diversity and small genetic distance (Nei's distance 0.07 or less) among six populations from China are consistent with wide dispersal of wild oat in the 1980s. Our results indicate that the wild oat populations in China are genetically diverse at a level similar to North America, and the genetic diversity of wild oat in the broad spatial scale is not substantially changed by environment, agronomic practices, or herbicide usage.

scholarly journals Genetic Diversity and Population Structure of Fusicladium effusum on Pecan in the United States

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 916-923 ◽  
Author(s):  
C. H. Bock ◽  
B. W. Wood ◽  
K. L. Stevenson ◽  
R. S. Arias
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Population Structure ◽  
Linkage Disequilibrium ◽  
Gene Diversity ◽  
The United States ◽  
Individual Tree ◽  
Pecan Scab ◽  
The Individual ◽  
Average Gene

Fusicladium effusum causes pecan scab, which is the most destructive disease of pecan orchards in the United States. Conidia of the pathogen are spread by rain splash and wind. The fungus is pathogenically diverse; yet there is no information on its genetic diversity or population genetics. Universally primed polymerase chain reaction (UP-PCR) was used to investigate the genetic diversity and population structure on a hierarchical sample of 194 isolates collected from 11 orchard locations from Florida to Texas, consisting of three to four isolates from each of five to six trees at each location. Genetic variation was high throughout the region, with all but nine of the multilocus haplotypes being unique. Nei's average gene diversity ranged from 0.083 for a population from Mississippi to 0.160 for a population from Kansas. An analysis of molecular variance of the hierarchically sampled populations found that the majority of the genetic variability (82.6%) occurred at the scale of the individual tree and only relatively small amounts among populations in trees from an orchard (5.0%) or within groups (i.e., orchard location populations) (12.5%). The results suggest little population differentiation in F. effusum in the southeastern United States, although φpt values of genetic distance for pairwise comparisons indicated some populations could be differentiated from others. There was evidence of linkage disequilibrium in certain populations, and the common occurrence of asexual reproduction in F. effusum could lead to measurable linkage disequilibrium under certain circumstances. However, the degree of genetic diversity and the scale over which diversity is distributed is evidence that F. effusum undergoes regular recombination despite no known sexual stage.

scholarly journals AFLP Comparisons Among Claviceps africana Isolates from the United States, Mexico, Africa, Australia, India, and Japan

Plant Disease ◽  
2002 ◽  
Vol 86 (11) ◽  
pp. 1247-1252 ◽  
Author(s):  
Paul W. Tooley ◽  
Erin D. Goley ◽  
Marie M. Carras ◽  
Nichole R. O'Neill
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Fragment Length Polymorphism ◽  
Genetic Relationships ◽  
The United States ◽  
The Other ◽  
Population Subdivision ◽  
Future Studies ◽  
Claviceps Africana ◽  
United States Mexico

Eighty-seven isolates of the sorghum ergot pathogen, Claviceps africana, from diverse geographic locations were analyzed using four different amplified fragment length polymorphism (AFLP) primer combinations to determine genetic relationships among isolates. Most isolates showed unique AFLP haplotypes, indicating that substantial genetic variation is present within C. africana populations. Two major groupings of isolates were observable, with ca. 70% similarity between the two groups. One group consisted of Australian, Indian, and Japanese isolates and the other of U.S., Mexican, and African isolates. In spite of overall high levels of genetic diversity observed in C. africana, isolates within the two major groups were between 75 and 100% similar. The observed associations of C. africana isolates from worldwide sources could be the result of intercontinental trade and/or movement of seed. The data indicate that Africa was the likely source of C. africana that has become established in the Americas since 1996. Analysis of additional isolates in future studies will reveal whether these groupings are being maintained or whether population subdivision or reshuffling may occur.

Wrestling with 9/11: Immigrant Perceptions and Perceptions of Immigrants

2006 ◽  
Vol 3 (2) ◽  
pp. 107-124 ◽  
Author(s):  
Caroline Brettell
Keyword(s):  
United States ◽  
Immigration Policy ◽  
Asian Indians ◽  
World Trade Center ◽  
The United States ◽  
Fort Worth ◽  
Foreign Born ◽  
Immigrant Populations ◽  
Trade Center ◽  
The Impact

Soon after 9/11 a research project to study new immigration into the Dallas Fort Worth metropolitan area got under way. In the questionnaire that was administered to 600 immigrants across five different immigrant populations (Asian Indians, Vietnamese, Mexicans, Salvadorans, and Nigerians) between 2003 and 2005 we decided to include a question about the impact of 9/11 on their lives. We asked: “How has the attack on the World Trade Center on September 11, 2001 affected your position as an immigrant in the United States?” This article analyzes the responses to this question, looking at similarities and differences across different immigrant populations. It also addresses the broader issue of how 9/11 has affected both immigration policy and attitudes toward the foreign-born in the United States. 

Anne O. Krueger, Constantine Michalopoulos and Vernon W. Ruttan. Aid and Development. Baltimore: The Johns Hopkins University Press. 1989. xiv + 386 pp.Price: U.S. $ 52.00

1991 ◽  
Vol 30 (2) ◽  
pp. 213-217
Author(s):  
Mir Annice Mahmood
Keyword(s):  
United States ◽  
Economic Development ◽  
International Development ◽  
Western Europe ◽  
Development Assistance ◽  
The United States ◽  
Social Infrastructure ◽  
Low Literacy ◽  
The Subject ◽  
The Impact

Foreign aid has been the subject of much examination and research ever since it entered the economic armamentarium approximately 45 years ago. This was the time when the Second World War had successfully ended for the Allies in the defeat of Germany and Japan. However, a new enemy, the Soviet Union, had materialized at the end of the conflict. To counter the threat from the East, the United States undertook the implementation of the Marshal Plan, which was extremely successful in rebuilding and revitalizing a shattered Western Europe. Aid had made its impact. The book under review is by three well-known economists and is the outcome of a study sponsored by the Department of State and the United States Agency for International Development. The major objective of this study was to evaluate the impact of assistance, i.e., aid, on economic development. This evaluation however, was to be based on the existing literature on the subject. The book has five major parts: Part One deals with development thought and development assistance; Part Two looks at the relationship between donors and recipients; Part Three evaluates the use of aid by sector; Part Four presents country case-studies; and Part Five synthesizes the lessons from development assistance. Part One of the book is very informative in that it summarises very concisely the theoretical underpinnings of the aid process. In the beginning, aid was thought to be the answer to underdevelopment which could be achieved by a transfer of capital from the rich to the poor. This approach, however, did not succeed as it was simplistic. Capital transfers were not sufficient in themselves to bring about development, as research in this area came to reveal. The development process is a complicated one, with inputs from all sectors of the economy. Thus, it came to be recognized that factors such as low literacy rates, poor health facilities, and lack of social infrastructure are also responsible for economic backwardness. Part One of the book, therefore, sums up appropriately the various trends in development thought. This is important because the book deals primarily with the issue of the effectiveness of aid as a catalyst to further economic development.

The link between coronavirus, anxiety, and religious beliefs in the United States and United Kingdom

2020 ◽  
Author(s):  
Francesco Rigoli
Keyword(s):  
United States ◽  
United Kingdom ◽  
Religious Beliefs ◽  
Well Being ◽  
The United States ◽  
Christian Faith ◽  
Stressful Event ◽  
Cultural Implications ◽  
The Impact

Research has shown that stress impacts on people’s religious beliefs. However, several aspects of this effect remain poorly understood, for example regarding the role of prior religiosity and stress-induced anxiety. This paper explores these aspects in the context of the recent coronavirus emergency. The latter has impacted dramatically on many people’s well-being; hence it can be considered a highly stressful event. Through online questionnaires administered to UK and USA citizens professing either Christian faith or no religion, this paper examines the impact of the coronavirus crisis upon common people’s religious beliefs. We found that, following the coronavirus emergency, strong believers reported higher confidence in their religious beliefs while non-believers reported increased scepticism towards religion. Moreover, for strong believers, higher anxiety elicited by the coronavirus threat was associated with increased strengthening of religious beliefs. Conversely, for non-believers, higher anxiety elicited by the coronavirus thereat was associated with increased scepticism towards religious beliefs. These observations are consistent with the notion that stress-induced anxiety enhances support for the ideology already embraced before a stressful event occurs. This study sheds light on the psychological and cultural implications of the coronavirus crisis, which represents one of the most serious health emergencies in recent times.

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