scholarly journals Flowering Patterns of Pollenizer and Triploid Watermelon Cultivars

HortScience ◽  
2014 ◽  
Vol 49 (6) ◽  
pp. 714-721 ◽  
Author(s):  
Cecilia E. McGregor ◽  
Vickie Waters
Keyword(s):  
United States ◽  
Fruit Set ◽  
Citrullus Lanatus ◽  
Staminate Flower ◽  
The United States ◽  
Specific Production ◽  
The Past ◽  
Seedless Watermelon ◽  
Triploid Watermelon ◽  
Fundamental Requirement

The past 10 years has seen a steep increase in production of seedless watermelon (Citrullus lanatus) in the United States. Seedless fruit is produced on triploid plants that require pollination from diploid pollenizers for fruit set. Synchronization of the staminate flowers on the pollenizers with the appearance of pistillate flowers on the triploids is a fundamental requirement for this production system. Previous research suggested that pistillate flowers reach peak production early in the season, but data are only available for a small number of triploid cultivars. We compared the flowering patterns of 29 triploid cultivars and 20 pollenizers, including 10 harvested pollenizers, during the first 6 weeks after transplanting over 2 years. The average number of days from transplanting (DAT) to the first staminate flower was between 5.3 days and 19.1 days in 2012 and 9.7 days and 24.4 days in 2013 for the pollenizers and between 18.7 days and 27.6 days and 22.1 days and 32.7 days for the pistillate triploid flowers in the 2 years, respectively. K-means clustering of the weekly percentage of plants with staminate and pistillate flowers for the different cultivars shows that different triploid and pollenizer cultivars have different flowering patterns and that some combinations have better synchronized flowering than others. Growers should take particular care when choosing pollenizers for early-flowering triploid cultivars. Harvested pollenizers are better suited to late-flowering triploids and growers should choose triploid and pollenizer cultivar combinations with flowering patterns that best satisfy their specific production goals.

scholarly journals Scarification and Moisture Effects on Triploid Watermelon Seed Germination

HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 553C-553b
Author(s):  
S. Grange ◽  
D.I. Leskovar ◽  
L. Pike ◽  
G. Cobb
Keyword(s):  
United States ◽  
Hydrogen Peroxide ◽  
Seed Germination ◽  
Citrullus Lanatus ◽  
The United States ◽  
Watermelon Seed ◽  
Seed Moisture ◽  
Moisture Effects ◽  
Air Space ◽  
Triploid Watermelon

Triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] consumption is increasing in the United States However, some of the original problems, poor and inconsistent germination, still exist. Seeds of several triploid and diploid watermelon cultivars were subjected to a variety of treatments to improve germination. Control and scarified seeds, by nicking, were incubated at 25 or 30 °C in either 5 or 10 mL H2O or hydrogen peroxide (H2O2). Triploid seed germination was strongly inhibited in all cultivars when seeds were at 10 mL of H2O or H2O2; both nicking and H2O2 increased germination but not equal to rate of the control in 5 mL H2O or H2O2. Germination of diploid cultivars was unaffected by any treatment. Seed morphological measurments indicated that triploid seed has a smaller embryo with a large and highly variable (cv = 105%) air space surrounding the embryonic axis as compared with the diploid seed. These data suggests that triploid watermelon seed germination is not inhibited by the seed coat thickness alone. Seed moisture plays a significant role in germination, emergence, and stand uniformity.

scholarly journals UPDATE ON POWDERY MILDEW RESISTANCE SCREENING IN WATERMELON

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 872c-872
Author(s):  
Angela R. Davis ◽  
Todd C. Wehner ◽  
Amnon Levi ◽  
Stephen R. King
Keyword(s):  
United States ◽  
South Carolina ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Citrullus Lanatus ◽  
Germplasm Collection ◽  
The United States ◽  
The Past ◽  
Race 1 ◽  
Race 2

Powdery mildew has been reported on Citrullus lanatus in Africa and Europe for the past 9 years, and in the United States for the past 6 years. During this time, it has occurred in the main watermelon production areas in the U.S. and has been documented in nine states (South Carolina, Georgia, Florida, Oklahoma, Texas, Maryland, New York, Arizona, and California). This is of great concern to the watermelon industry since powdery mildew is difficult to control and can have a severe impact on yield and fruit quality due to loss of photosynthetic area and sunscald. Finding resistant C. lanatus germplasm is needed for the development of commercial varieties containing this resistance. This report summarized the status of an ongoing project to screen the entire USDA–ARS C. lanatus germplasm collection. Currently, the collection is being screened for race 1 and race 2 Podosphaera xanthii (syn. Sphaerotheca fuliginea auct. p.p.), the causal agent of powdery mildew in C. lanatus in the United States. Resistance genes appear to exist for both races and the genes conferring resistance to race 1 appear to be different than race 2 resistance genes. Allelism tests are currently in process to determine the number of resistance genes present.

scholarly journals UPDATE ON POWDERY MILDEW RESISTANCE SCREENING IN WATERMELON

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 871a-871
Author(s):  
Angela R. Davis ◽  
Todd C. Wehner ◽  
Amnon Levi ◽  
Stephen R. King
Keyword(s):  
United States ◽  
South Carolina ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Citrullus Lanatus ◽  
Germplasm Collection ◽  
The United States ◽  
The Past ◽  
Race 1 ◽  
Race 2

Powdery mildew has been reported on Citrullus lanatus in Africa and Europe for the past nine years, and in the United States for the past 6 years. During this time, it has occurred in the main watermelon production areas in the U.S. and has been documented in nine states (South Carolina, Georgia, Florida, Oklahoma, Texas, Maryland, New York, Arizona, and California). This is of great concern to the watermelon industry since powdery mildew is difficult to control and can have a severe impact on yield and fruit quality due to loss of photosynthetic area and sunscald. Finding resistant C. lanatus germplasm is needed for the development of commercial varieties containing this resistance. This report summarized the status of an ongoing project to screen the entire USDA–ARS C. lanatus germplasm collection. Currently, the collection is being screened for race 1 and race 2 Podosphaera xanthii (syn. Sphaerotheca fuliginea auct. p.p.), the causal agent of powdery mildew in C. lanatus in the United States. Resistance genes appear to exist for both races and the genes conferring resistance to race 1 appear to be different than race 2 resistance genes. Allelism tests are currently in process to determine the number of resistance genes present.

International Research and Variation in Views of Ethnicity

2012 ◽  
Vol 2 (2) ◽  
pp. 66-72
Author(s):  
Ella Inglebret ◽  
Amy Skinder-Meredith ◽  
Shana Bailey ◽  
Carla Jones ◽  
Ashley France
Keyword(s):  
United States ◽  
Classification System ◽  
International Research ◽  
The United States ◽  
Research Articles ◽  
Journal Articles ◽  
Research Participants ◽  
The Past ◽  
International Scale ◽  
Publication Patterns

The authors in this article first identify the extent to which research articles published in three American Speech-Language-Hearing Association (ASHA) journals included participants, age birth to 18 years, from international backgrounds (i.e., residence outside of the United States), and go on to describe associated publication patterns over the past 12 years. These patterns then provide a context for examining variation in the conceptualization of ethnicity on an international scale. Further, the authors examine terminology and categories used by 11 countries where research participants resided. Each country uses a unique classification system. Thus, it can be expected that descriptions of the ethnic characteristics of international participants involved in research published in ASHA journal articles will widely vary.

Proportion of Individuals With Past-Year Suicidal Ideation Who Attempted Suicide Over the Past 10 Years in the United States, and the Influence of Age and Sex

Crisis ◽  
2020 ◽  
pp. 1-5
Author(s):  
Shannon Lange ◽  
Courtney Bagge ◽  
Charlotte Probst ◽  
Jürgen Rehm
Keyword(s):  
United States ◽  
Suicidal Ideation ◽  
Random Effects ◽  
Attempted Suicide ◽  
Suicide Attempts ◽  
The United States ◽  
Individual Level ◽  
The Past ◽  
Meta Analyses ◽  
Age Category

Abstract. Background: In recent years, the rate of death by suicide has been increasing disproportionately among females and young adults in the United States. Presumably this trend has been mirrored by the proportion of individuals with suicidal ideation who attempted suicide. Aim: We aimed to investigate whether the proportion of individuals in the United States with suicidal ideation who attempted suicide differed by age and/or sex, and whether this proportion has increased over time. Method: Individual-level data from the National Survey on Drug Use and Health (NSDUH), 2008–2017, were used to estimate the year-, age category-, and sex-specific proportion of individuals with past-year suicidal ideation who attempted suicide. We then determined whether this proportion differed by age category, sex, and across years using random-effects meta-regression. Overall, age category- and sex-specific proportions across survey years were estimated using random-effects meta-analyses. Results: Although the proportion was found to be significantly higher among females and those aged 18–25 years, it had not significantly increased over the past 10 years. Limitations: Data were self-reported and restricted to past-year suicidal ideation and suicide attempts. Conclusion: The increase in the death by suicide rate in the United States over the past 10 years was not mirrored by the proportion of individuals with past-year suicidal ideation who attempted suicide during this period.

EDITORIAL: Migration and competitiveness: Japan and the United States

2013 ◽  
Vol 10 (2) ◽  
pp. 115-124
Author(s):  
Philip L. Martin
Keyword(s):  
United States ◽  
The United States ◽  
Variable Cost ◽  
Fixed Cost ◽  
Special Issue ◽  
Science And Engineering ◽  
The Past ◽  
Past Half Century ◽  
Key Sectors ◽  
Past Half

Japan and the United States, the world’s largest economies for most of the past half century, have very different immigration policies. Japan is the G7 economy most closed to immigrants, while the United States is the large economy most open to immigrants. Both Japan and the United States are debating how immigrants are and can con-tribute to the competitiveness of their economies in the 21st centuries. The papers in this special issue review the employment of and impacts of immigrants in some of the key sectors of the Japanese and US economies, including agriculture, health care, science and engineering, and construction and manufacturing. For example, in Japanese agriculture migrant trainees are a fixed cost to farmers during the three years they are in Japan, while US farmers who hire mostly unauthorized migrants hire and lay off workers as needed, making labour a variable cost.

Democratic Legitimacy

2011 ◽  
Author(s):  
Pierre Rosanvallon
Keyword(s):  
United States ◽  
The United States ◽  
Democratic Legitimacy ◽  
Political Leaders ◽  
Constitutional Courts ◽  
International Debate ◽  
The Past ◽  
Democratic Authority ◽  
Original Contribution ◽  
Western Democracies

It's a commonplace occurrence that citizens in Western democracies are disaffected with their political leaders and traditional democratic institutions. But this book argues that this crisis of confidence is partly a crisis of understanding. The book makes the case that the sources of democratic legitimacy have shifted and multiplied over the past thirty years and that we need to comprehend and make better use of these new sources of legitimacy in order to strengthen our political self-belief and commitment to democracy. Drawing on examples from France and the United States, the book notes that there has been a major expansion of independent commissions, NGOs, regulatory authorities, and watchdogs in recent decades. At the same time, constitutional courts have become more willing and able to challenge legislatures. These institutional developments, which serve the democratic values of impartiality and reflexivity, have been accompanied by a new attentiveness to what the book calls the value of proximity, as governing structures have sought to find new spaces for minorities, the particular, and the local. To improve our democracies, we need to use these new sources of legitimacy more effectively and we need to incorporate them into our accounts of democratic government. This book is an original contribution to the vigorous international debate about democratic authority and legitimacy.

The Riddle of a Common History

2009 ◽  
Vol 1 (1) ◽  
pp. 93-116 ◽  
Author(s):  
Mauricio Tenorio-Trillo
Keyword(s):  
United States ◽  
Common Ground ◽  
The United States ◽  
History Textbooks ◽  
Recent History ◽  
History Textbook ◽  
The Past ◽  
The Us ◽  
Constant Part ◽  
Intrinsic Component

By identifying two general issues in recent history textbook controversies worldwide (oblivion and inclusion), this article examines understandings of the United States in Mexico's history textbooks (especially those of 1992) as a means to test the limits of historical imagining between U. S. and Mexican historiographies. Drawing lessons from recent European and Indian historiographical debates, the article argues that many of the historical clashes between the nationalist historiographies of Mexico and the United States could be taught as series of unsolved enigmas, ironies, and contradictions in the midst of a central enigma: the persistence of two nationalist historiographies incapable of contemplating their common ground. The article maintains that lo mexicano has been a constant part of the past and present of the US, and lo gringo an intrinsic component of Mexico's history. The di erences in their historical tracks have been made into monumental ontological oppositions, which are in fact two tracks—often overlapping—of the same and shared con ictual and complex experience.

The Challenges of Displaying “Asian American”: Curatorial Perspectives and Critical Approaches

2007 ◽  
Vol 5 (1) ◽  
pp. 12-32
Author(s):  
ShiPu Wang
Keyword(s):  
United States ◽  
Asian American ◽  
Financial Support ◽  
American Art ◽  
The United States ◽  
Community Leaders ◽  
Art Exhibitions ◽  
The Past ◽  
Critical Approaches ◽  
Racial Demographics

This essay delineates the issues concerning AAPI art exhibitions from a curator’s perspective, particularly in response to the changing racial demographics and economics of the past decades. A discussion of practical, curatorial problems offers the reader an overview of the obstacles and reasons behind the lack of exhibitions of AAPI works in the United States. It is the author’s hope that by understanding the challenges particular to AAPI exhibitions, community leaders, and patrons will direct future financial support to appropriate museum operations, which in turn will encourage more exhibitions and research of the important artistic contribution of AAPI artists to American art.

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