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Full-Text Articles in Life Sciences
Genetic Dissection And Qtl Pyramiding To Enhance Salinity Tolerance In Rice (Oryza Sativa L.), Sandeep Chapagain
Genetic Dissection And Qtl Pyramiding To Enhance Salinity Tolerance In Rice (Oryza Sativa L.), Sandeep Chapagain
LSU Doctoral Dissertations
Salinity is emerging as a major threat to rice production worldwide due to climate change and anthropogenic sources. We performed three different population development approaches using exotic salt tolerant donors in US rice backgrounds to identify the salt tolerant QTLs/genes and tolerant breeding lines. First approach involved development of a biparental introgression lines (ILs) population by utilizing a salinity tolerant donor ‘TCCP’ in an elite rice cultivar ‘Cheniere’ background and mapping of QTLs at germination, seedling, and reproductive stages A total of seven QTLs for five germination traits, 16 QTLs for seven seedling stage traits, and 30 QTLs for ten …
Impact Of New Technologies On Weed Control In Louisiana Rice Production, David C. Walker
Impact Of New Technologies On Weed Control In Louisiana Rice Production, David C. Walker
LSU Doctoral Dissertations
Field studies were conducted in 2018-2021 at the LSU Agricultural Center’s H.R. Caffey Rice Research Station (RRS) near Crowley, LA, and the Dean Lee Research and Extension Center (DLREC) near Alexandria, LA to evaluate off-target florpyrauxifen movement on soybean. Soybean was treated with florpyrauxifen at the V4-V5 or R1-R2 growth stages. Soybean injury was evaluated at 1, 7, 14, and 28 days after treatment (DAT) and soybean plant height (cm) was recorded at 7, 14, and 28 DAT. At soybean maturity, yield and individual yield components were subjected to regression analysis to describe the relationship between florpyrauxifen rate and soybean …
Silicate-Solubilizing Bacteria In Louisiana Soils: Identification, Profiling, And Functions In Crop Production, Jayvee A. Cruz
Silicate-Solubilizing Bacteria In Louisiana Soils: Identification, Profiling, And Functions In Crop Production, Jayvee A. Cruz
LSU Doctoral Dissertations
Studies were conducted to determine the potential of silicate-solubilizing bacteria (SSB) as biostimulant in Louisiana rice (Oryza sativa L.) production systems. Isolation and profiling of SSB in Louisiana soils; evaluation on its effects on the silicon (Si) uptake and productivity of rice using various carriers derived from slag, rice hull, and sugarcane (Officinarum spp.) bagasse; and development of a feasible approach of incorporating SSB to the rice production system were conducted. Results showed that numerous bacteria isolated from Louisiana soils can solubilize silicate and produce multiple plant growth-promoting compounds. These potential SSBs were identified into four genera: Aeromonas, …
Rice Response To Nitrogen Fertilization And Comparison Of Unmanned Aerial Systems And Active Crop Canopy Sensors Vegetative Index To Estimate Rice Yield Potential, Anna Coker
LSU Master's Theses
Nitrogen (N) fertilization is a key component in producing profitable, maximized rice grain yields because yield is directly affected by N fertilizer applications. Economical optimum N rate (EONR) is used to estimate where the N fertilization rate impacts rice grain yield but is still economically efficient. Three common response models, linear-plateau, quadratic-plateau, and quadratic models were used to determine the response of rice to N fertilizer to determine the optimum N fertilization rate. The objective of the first part of this study was to evaluate the models by assessing the coefficients of determination (R2), maximum rice grain yields …
Silicon Fertilization In Rice And Wheat: Dynamics With Trace Elements And Effect Of Silicate Slag Granular Size On The Release Pattern Of Monosilicic Acid In Soil, Wooiklee S. Paye
Silicon Fertilization In Rice And Wheat: Dynamics With Trace Elements And Effect Of Silicate Slag Granular Size On The Release Pattern Of Monosilicic Acid In Soil, Wooiklee S. Paye
LSU Doctoral Dissertations
Studies were conducted to evaluate the impact of silicon (Si) fertilization on the uptake of harmful trace elements in Louisiana rice production system, and document the effect of silicate slag granular size on its ability to supply Si in wheat. The influence of silicate slag and lime on the uptake and translocation of harmful trace elements in rice grain was determined. Results showed that both slag and lime had similar effects on pH at five of the nine sites investigated. Soil Si was significantly (P <0.001) increased with application of silicate slag at all sites. Lime and silicate slag had no effect on the concentration of trace elements in soil. However, increasing Si rates were negatively correlated with arsenic (As) and cadmium (Cd) concentration in rice grain. The release pattern of monosilicic acid (H4SiO4) from wollastonite and silicate slag was compared in a wheat greenhouse …
Strategies To Overcome Antagonism Of Quizalofop-P-Ethyl When Applied In Mixture With Other Herbicides, Lucas C. Webster
Strategies To Overcome Antagonism Of Quizalofop-P-Ethyl When Applied In Mixture With Other Herbicides, Lucas C. Webster
LSU Master's Theses
A field study was conducted in 2017 and 2018 at the LSU Agricultural Center H. Rouse Caffey Rice Research Station (RRS) near Crowley, LA. to evaluate the influence of different adjuvants in overcoming the antagonism of quizalofop when mixed with bispyribac in Louisiana rice production. The antagonism of quizalofop mixed with bispyribac plus HCOC at 14 DAIT was overcome with a neutral interaction observed at 28 DAIT for barnyardgrass control with an observed control of 91%, compared with an expected control of 97%. The addition of COC, SNS or HCOC into a mixture of quizalofop plus bispyribac provided synergistic or …
The Tripartite Interaction Between Arbuscular Mycorrhizal Fungi, Rice, And Insects, Lina Bernaola Alvarado
The Tripartite Interaction Between Arbuscular Mycorrhizal Fungi, Rice, And Insects, Lina Bernaola Alvarado
LSU Doctoral Dissertations
Losses caused by pests remain an important limitation to achieving high rice yields in the United States. Arbuscular mycorrhizal fungi (AM fungi) are able to modify plant physiology by increasing plant growth or inducing defense responses against insect herbivores. However, studies of the role of AM fungi in agroecological factors, including natural occurrence, plant resistance, soil dependency, and plant tolerance, with specific regards to pests that feed on rice plants have not been conducted before. A three-year study revealed natural occurring colonization by AM fungi on rice roots sampled in four rice-producing areas in the southern United States. Overall, rice-AM …
Effect Of Increasing Levels Of Monosilicic Acid On Arsenic And Phosphorus Sorption In Soil, Flávia Bastos Agostinho
Effect Of Increasing Levels Of Monosilicic Acid On Arsenic And Phosphorus Sorption In Soil, Flávia Bastos Agostinho
LSU Doctoral Dissertations
Arsenic (As) accumulation in rice (Oryza sativa) grains has increased human’s daily intake. Studies have shown that arsenite is taken up through known silicon (Si) transporters in rice. Moreover, the availability of As in soil is affected by chemically similar ligands that have high affinity to oxides surfaces, such as Si and phosphorus (P). Studies were conducted to: (I) investigate the role of elevated levels of Si on the concentration of different As fractions in soil and on As uptake by rice; (II) evaluate the effect of increasing monosilicic acidconcentrations on As sorption and kinetics in soil; and …
The Determinants Of Nucleosome Patterns And The Impact Of Phosphate Starvation On Nucleosome Patterns And Gene Expression In Rice, Qi Zhang
LSU Doctoral Dissertations
In eukaryotic cells, DNA is a large molecule that must be greatly condensed to fit within the nucleus. DNA is wrapped around histone proteins to form nucleosomes, which facilitate DNA condensation, but on the other hand, may limit DNA processes. Organisms must respond to environmental stress in order to survive, and one strategy is by remodeling nucleosomes to promote changes in DNA accessibility to alter gene expression. Studies have demonstrated a clear correlation between nucleosome dynamics and transcriptional change in some eukaryotes, however factors that affect nucleosome positioning in plants are largely unknown, and the correlation between nucleosome dynamics and …
Activity Of Benzobicyclon Herbicide In Common Louisiana Rice Production Practices, Benjamin M. Mcknight
Activity Of Benzobicyclon Herbicide In Common Louisiana Rice Production Practices, Benjamin M. Mcknight
LSU Doctoral Dissertations
A study was conducted at the LSU AgCenter H. Rouse Caffey Rice Research Station (RRS) to evaluate benzobicyclon herbicide application timing on water-seeded rice. Benzobicyclon was applied at seven different timings, at 246 g ai ha-1 in a water-seeded rice production system. Benzobicyclon controlled ducksalad above 90% when applied into the pinpoint flood. Barnyardgrass control was greater than 90% from applications made on pegging rice and immediately following pinpoint flood establishment. At 49 days after treatment (DAT), yellow nutsedge control exceeded 90% following benzobicyclon treatment with a pegging rice or pinpoint flood timing. Ducksalad control was greater than 90% following …
Quizalofop-P-Ethyl Herbicide Interactions In Accase-Resistant Rice Production, Samer Y. Rustom Jr.
Quizalofop-P-Ethyl Herbicide Interactions In Accase-Resistant Rice Production, Samer Y. Rustom Jr.
LSU Master's Theses
A field study was conducted in 2015 and 2016 at the H. Rouse Caffey Rice Research Station (RRS) to evaluate mixture interactions of quizalofop and ALS-inhibiting herbicides. Quizalofop was applied at 120 g ai ha-1. Mixture herbicides included penoxsulam at 40 g ha-1, penoxsulam plus triclopyr at 352 g ha-1, halosulfuron at 53 g ha-1, bispyribac at 34 g ha-1, orthosulfamuron plus halosulfuron at 94 g ha-1, orthosulfamuron plus quinclorac at 491 g ha-1, imazosulfuron at 211 g ha-1, and bensulfuron at 43 g ha-1. All ALS herbicides mixed with quizalofop indicated antagonistic responses for weedy rice or barnyardgrass control …
Nealley's Sprangletop (Leptochloa Nealleyi Vasey) Management And Interference In Rice Production, Eric Allen Bergeron
Nealley's Sprangletop (Leptochloa Nealleyi Vasey) Management And Interference In Rice Production, Eric Allen Bergeron
LSU Master's Theses
A glasshouse study was conducted on the Louisiana State University campus in Baton Rouge to evaluate herbicide activity on Nealley's sprangletop. Herbicides were applied to Nealley’s sprangletop plants in the one-two tiller stage with height of 20-30 cm. Nealley's sprangletop control, leaf number, height, tiller number, and fresh weight biomass were evaluated. Nealley's sprangletop treated with glyphosate, quizalofop, fenoxaprop, and clethodim was controlled 89 to 99%. A field study was conducted at the LSU AgCenter Rice Research Station (RRS) and a grower location (GL) to evaluate herbicide rates and timings for control of Nealley's sprangletop in drill-seeded rice. Herbicide treatments …
Molecular Genetics Of Cold Tolerance At Germination And Seedling Stages In Rice, Anna Hissahe Borjas Artica
Molecular Genetics Of Cold Tolerance At Germination And Seedling Stages In Rice, Anna Hissahe Borjas Artica
LSU Master's Theses
Low temperature stress is a major constraint for rice production in temperate and high altitude areas of the world. Delayed germination coupled with reduced seedling vigor hinders crop establishment and crop growth resulting in reduced rice productivity. Mapping of chromosomal regions controlling cold tolerance will accelerate marker-assisted breeding of cold tolerant rice varieties. A recombinant inbred line (RIL) mapping population involving a rice cultivar ‘Bengal’ and a US weedy rice accession ‘PSRR-1’ was evaluated for cold tolerance at both germination and seedling stages. Observations on germinating ability and seedling vigor were recorded under both low temperature (13oC) and optimum temperature …
Molecular Genetics Of Salinity Tolerance In Rice (Oryza Sativa L.), Teresa Bermejo De Leon
Molecular Genetics Of Salinity Tolerance In Rice (Oryza Sativa L.), Teresa Bermejo De Leon
LSU Doctoral Dissertations
Due to the threat of salinity stress to Louisiana rice production, an effort was made to understand the molecular genetics of salinity tolerance with the overall goal of developing salt tolerant varieties. The objectives of this study were to 1) determine if salinity tolerance exist in the US rice varieties, 2) map the additive and epistatic QTLs for traits related to seedling salinity tolerance in recombinant inbred lines (RILs) using genotyping-by-sequencing (GBS)-derived SNP markers, and 3) identify and validate stable QTLs and their effects in introgression lines (ILs) of Pokkali in Bengal background. All experiments for phenotypic characterization were conducted …
Development Of A Loop-Mediated Isothermal Amplification For The Detection Of Burkholderia Glumae, Maria Alejandra Caldera
Development Of A Loop-Mediated Isothermal Amplification For The Detection Of Burkholderia Glumae, Maria Alejandra Caldera
LSU Master's Theses
Bacterial panicle blight is among the three most limiting diseases of rice production in the United States. Yield loss up to 40% has been reported from rice fields severely infested with bacterial panicle blight. The disease is caused by Burkholderia glumae and B. gladioli. Although, both species produce similar symptoms and are closely related, but B. glumae strains are more aggressive and cause more severe symptoms on rice. Bacterial panicle bight is difficult to manage in the absence of effective chemical control measures. Rapid and early disease detection is needed to avoid severe yield losses. Several techniques have been developed …
Physiological, Biochemical And Molecular Characteristics Associated With Virulence Of Burkholderia Glumae: The Major Causative Agent Of Bacterial Panicle Blight Of Rice, Hari Sharan Karki
Physiological, Biochemical And Molecular Characteristics Associated With Virulence Of Burkholderia Glumae: The Major Causative Agent Of Bacterial Panicle Blight Of Rice, Hari Sharan Karki
LSU Master's Theses
Burkholderia glumae is the bacterial pathogen causing bacterial panicle blight disease of rice (BPB). The pathogen, whose growth and pathogenicity is favored by high temperatures, has become a serious threat to rice production around the world possibly due to the current global climate changes. In this study, previously reported avirulent B. glumae strains were characterized in respect to the production of known virulence factors, toxoflavin, lipase and motility, and potential virulence factors, including polygalacturnase and type III secretion system (hypersensitive response). Considerable phenotypic variation was observed among the strains tested. Virulence of the B. glumae strains was closely related to …
Studies On Rice Transformation And The Use Of Transformed Plants [Electronic Resource], Qiming Shao
Studies On Rice Transformation And The Use Of Transformed Plants [Electronic Resource], Qiming Shao
LSU Doctoral Dissertations
This research was conducted to enhance utilization of the Liberty herbicide resistance transgene in rice. Non-lethal methods to determine the sensitivity of transgenic rice plants to hygromycin B and Liberty were developed, tested and used in this research. Four homozygous transformed plants were selected to make reciprocal crosses with their non-transformed parent cultivars Taipei 309 and Nipponbare. Their resistances to Liberty and hygromycin B were controlled by the closely linked single dominant genes bar and hpt. Some non-resistant phenotypes in the F2 populations were due to gene silencing. The bar gene in some of these plants were allelic and some …