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Disaggregating The Effect Of Drought And Heat Stress During Flowering On Spikelet Fertility In Rice, Lisa Straussberger

Graduate Theses and Dissertations

Due to rice’s wide geographic distribution, extending from 50°N to 35°S, rice is

forecasted to be the most vulnerable crop to warming global climates. Previous studies have

predicted lower rice yields and increasing rice yield variability due to higher frequencies of heat

stress events, and a higher variability in precipitation patterns due to global warming. As such,

understanding the effects of drought and heat stress intensity and frequency on rice yields is of

upmost importance to feeding the growing global population.

Given that drought and high-temperature stress often occur together, it is essential to

disaggregate the two individual stressors and …

A Regional Approach To Analysis Of Food Security Framework And Policies Of The Economic Community Of West African States (Ecowas), Hannah Elizabeth Shear

Graduate Theses and Dissertations

Food security is always a concern for consumers, but especially for those in West Africa, where the population of food insecure people has continued to grow over the past decade despite attempts by initiatives such as the World Food Program and the establishment of Millennium Development Goals. The people of West Africa are subject to repetitive natural disasters and are often in political upheaval. Many economic policies have been established to mitigate the impact that production disasters have on the consumers; one of these policies is the utilization of regional food reserves.

In 2010, the Economic Community of West African …

Validation Of Soil-Test-Based Phosphorus And Potassium Fertilizer Recommendations For Rice And Soybean, Matthew Scott Fryer

Graduate Theses and Dissertations

The science of soil-testing for nutrient management and fertilizer recommendations is widely accepted among scientists and agronomists. Although this science is unsurpassed in predicting soil nutrient availability, soil-test interpretations are seldom validated. Major research objectives for irrigated soybean [Glycine max (L.) Merr.] and direct-seeded, delayed-flood rice (Oryza sativa L.) were to: i) validate the accuracy of Mehlich-3 soil-test P (STP) and K (STK) interpretations and ii) published critical tissue-P and -K interpretations in predicting the yield response to fertilizer at different significance levels (p≤0.05 to 0.25), iii) examine how seed nutrient concentrations are influenced by fertilization and crop response to …

A Simulation Platform For Accurate Prediction Of In-Bin Drying And Storage Of Rough Rice, Houmin Zhong

Graduate Theses and Dissertations

Natural air (NA), in-bin drying and storage of rough rice generally maintains high grain quality, but the associated slow movement and occasional stagnation of the drying front during the process may result in problems of rice quality reduction, mold growth, and mycotoxin development, especially for rough rice in the top layers of the bin. Using modeling techniques to simulate in-bin rough rice drying in typically-encountered field scenarios may provide a tool for rapidly predicting the grain condition as drying progresses. The objectives for this study were to (1) investigate accurate models for predicting equilibrium moisture content (EMC) of rough rice …

A Morpho-Physiological Analysis Of Diverse Drought Resistant And Sensitive Rice Genotypes To Identify Distinguishing Anatomical Root Phenes, Clinton Philip Greub

Graduate Theses and Dissertations

A set of 37 genotypes selected from a survey of over 200 diverse germplasms, for their diverse drought tolerance mechanisms, were analyzed in this study for root physiological traits that are indicative of different drought resistance mechanisms. The genotypes include controls such as the drought sensitive IR64 and Nipponbare, along with the drought resistant Nagina 22 (N22) and Bengal landraces to identify distinguishing phenotypic features of resistant accessions. Anatomical traits studied include total areas of the cross-sections of the stele, cortex, aerenchyma, cortical-cell, and xylem tissue; the number of aerenchyma, xylem vessels, cortical cell file number and size that together …

Evaluation Of Water And Nitrogen Management Practices In Southern Us Rice (Oryza Sativa L.) Production, Richard Lee Atwill

Theses and Dissertations

Nitrogen (N) fertility and irrigation costs are the greatest input expenses required for rice production in Mississippi, therefore N management and irrigation should be conducted in efficiently. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS, and the LSU AgCenter in Crowley, LA, to evaluate water and nitrogen management practices. Nitrogen use efficiency and yield were not different for alternate wetting and drying (AWD) systems compared to a traditional continuous flood. Additionally, experiments were conducted to test for differences comparing two experimental designs, randomized complete block (RCB) and split-plot (SP), for N-rate response trials in …

Family Ties: The Gibbs Family, Race, And Society In South Carolina: 1865-1945, Andre Thompson

Graduate Theses

The ancestors of the Gibbs family came to South Carolina as slaves from Barbados in the early 19th C., and four brothers, Anthony, Fortune, Moses and Wetus, born in South Carolina between 1832 and 1845, all grew up as slaves and became emancipated while they were still young men. This thesis will chronicle the lineage of these four brothers whose family serves as a microcosm of African American life in South Carolina and beyond. This includes an examination of the family from Reconstruction through the World War II period, and it will focus on issues such as emancipation, agriculture, landownership, …

Effect Of Germination And Parboiling On Milling, Physicochemical, And Textural Properties Of Medium- And Long-Grain Rough Rice, Ashley Han

Graduate Theses and Dissertations

Germinated brown rice is commonly consumed in Asia for its enhanced nutritional properties such as gamma-aminobutyric acid (GABA) and softer cooked texture. However germination decreases milling yield and alters some physicochemical properties, and most germinated rice studies evaluated medium-grain and aromatic rice cultivars. This study compared the effects of germination duration and parboiling on milling, physicochemical, and textural properties of a medium- (Jupiter) and a long-grain (Wells) rice cultivars. Rough rice was soaked in water at 25°C for 12 hr, and then incubated at 30-34°C for varying germination durations, or combined with parboiling at 120°C for 20 min prior to …

Methane Emissions From Direct-Seeded, Delayed-Flood Rice Grown On A Clay Soil, Alden Daniel Smartt

Graduate Theses and Dissertations

Due to the production of methane (CH4) under flooded-soil conditions, rice (Oryza sativa L.) cultivation is a major contributor to agricultural CH4 emissions. Studies examining CH4 emissions from rice have only recently been initiated in Arkansas and no data have been collected from rice produced on clay soils in Arkansas. Therefore, research was conducted in 2012 and 2013 at the Northeast Research and Extension Center in Keiser, Arkansas to examine the factors affecting CH4 emissions from rice produced on a Sharkey clay (very-fine, smectitic, thermic Chromic Epiaquerts). The objectives of this study were to determine: 1) the effect of vegetation …

Factors That Influence The Adoption Of Hermetic Storage, Evidence From Nepal, James Henry Flock

Open Access Theses

ABSTRACT

El Consenso De Washington Y Su Incidencia En El Sector Arrocero Colombiano: Efectos En La Seguridad Alimentaria 1990 2012, María Camila Manrique Fuentes, Magda Natalia Pineda Suescún

Finanzas y Comercio Internacional

El presente trabajo describe las políticas comerciales aplicadas a partir del Consenso de Washington que tuvieron un impacto en la seguridad alimentaria para el caso del arroz en Colombia. Las variables asociadas a la seguridad alimentaria como la producción, el consumo y los precios del arroz fueron estudiadas a través de análisis de tendencias y modelos de regresión lineal. Finalmente las autoras concluyen que la formulación de las políticas implementadas se llevó a cabo en total desvinculación con la realidad agrícola colombiana en términos del manejo de variables como la tasa de cambio y la tasa de interés. Situaciones importantes …

Development Of Disease Resistant Rice Using Whole Genome Sequencing And Standard Breeding Methods, Yamid Sanabria Gongora

LSU Doctoral Dissertations

Cultivated rice is the most important staple crop in the world, but diseases cause substantial losses in grain yield and quality. Sheath blight disease caused by the fungus Rhizoctonia solani is the second most important disease in rice. Most U.S varieties are tropical japonica type, but known sources of resistance in this subspecies are rare. Silva et al. (2012) identified candidate SNP associated with resistance to sheath blight by whole genome sequencing. The objectives of this study were to develop SNP-based markers from the information reported by Silva et al. (2012), to validate the markers by selective genotyping in the …

Wading Bird Food Availability In Rice Fields And Crawfish Ponds Of The Chenier Plain Of Southwest Louisiana And Southeast Texas, Cullen C. Foley

LSU Master's Theses

Wading birds in southwestern Louisiana and southeastern Texas rely heavily on rice fields and crawfish ponds as foraging areas; however, little information exists on food availability throughout the annual crop cycle. The objectives of this study are: 1) Develop a classification for rice and crawfish fields based upon tillage, forage crop (for crawfish fields), water depths, vegetation density, vegetation height, and other visible parameters; 2) Quantify the distribution of rice and crawfish fields in various stages across the landscape through time; 3) Determine the effects of rice and crawfish field types and landscape characteristics on wading bird use; and, 4) …

Effects Of Detrital Subsidy On Arthropod Communities In Louisiana Rice Fields And Predation On Rice Water Weevil (Lissorhoptrus Oryzophilus), Nathan Mercer

LSU Master's Theses

The rice water weevil (RWW), Lissorhoptrus oryzophilus (Kuschel), is the most important insect pest of rice in the United States. Integrated pest management strategies for RWW in Louisiana consist of cultural controls, resistant cultivars and chemical insecticides. The fourth component of IPM, biological control, is largely absent from the literature for RWW, making exploration of biological control a logical next step in developing a full set of IPM strategies. The three main types of biological control are augmentation, classical and conservation. With little known about RWW predators, conservation biological control makes the most sense as local natural enemy abundance is …