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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, …
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 …
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 …
Genetic Analyses Of Male Sterility And Wide Compatibility In U.S. Hybrid Rice Breeding Lines, Christian Torres De Guzman
Genetic Analyses Of Male Sterility And Wide Compatibility In U.S. Hybrid Rice Breeding Lines, Christian Torres De Guzman
LSU Doctoral Dissertations
Two line hybrid rice breeding is widely used in Asia and involves the use of environmentally-sensitive male sterile lines to achieve high grain yields compared to pure line varieties. Currently, there is limited information concerning the performance and inheritance of two indica male sterile lines 2008S and 2009S under U.S. field conditions. The first objective of the research herein was to characterize genetic male sterility of lines 2009S and 2008S under controlled environment conditions. Results showed that 2009S exhibited a thermosensitive response whereas little or no response was observed with changes in daylength. Furthermore, high pollen fertility was achieved at …
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 …
Mexican Rice Borer (Eoreuma Loftini) Pheromone Trap Efficacy And Role In Invasive Species Monitoring And Pest Management, Blake Emerson Wilson
Mexican Rice Borer (Eoreuma Loftini) Pheromone Trap Efficacy And Role In Invasive Species Monitoring And Pest Management, Blake Emerson Wilson
LSU Doctoral Dissertations
The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is an invasive pest of sugarcane, Saccharum spp.; rice, Oryza sativa; and other graminaceous crops along the U.S. Gulf Coast. Identification of E. loftini sex pheromones led to the development of pheromone baited traps. Studies were conducted to determine strategies for the use of E. loftini pheromone traps in invasive species monitoring and pest management. A two-year field study demonstrated that E. loftini pheromone traps attract males from distances of up to 100m. A behavioral assay observed that detection of the pheromone by E. loftini males occurs at ≈48m from the …
Development Of Disease Resistant Rice Using Whole Genome Sequencing And Standard Breeding Methods, Yamid Sanabria Gongora
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 …
Optimizing Yield And Crop Nitrogen Response Characterization By Integrating Spectral Reflectance And Agronomic Properties In Sugarcane And Rice, Yumiko Kanke
LSU Doctoral Dissertations
Nitrogen (N) is one of the most important and limiting nutrients in crop production. The best management practices for N fertilization is always challenging due to its dynamic system in the nature. Remote sensing has emerged as one of the most useful technologies in modern agriculture for non-invasive monitoring of plant N status. The objectives of this research were to 1) determine the effect of water background turbidity and depth on red and red-edge reflectance based prediction models for biomass and grain yield in rice, 2) evaluate agronomic parameters of different sugar cane varieties in response to variable levels of …
Development Of Integrated Pest Management For Sugarcane Borer, Diatraea Saccharalis In Rice, Jaspreet Kaur Sidhu
Development Of Integrated Pest Management For Sugarcane Borer, Diatraea Saccharalis In Rice, Jaspreet Kaur Sidhu
LSU Doctoral Dissertations
Rice is grown over an area of approximately 500,000 acres in Louisiana. The lepidopteran stem borer complex attacking rice in the southern U.S includes stalk borer Chilo plejadellus Zincken, sugarcane borer (SCB) Diatraea saccharalis (F.) and Mexican rice borer, Eoreuma loftini Dyar. With the increasing impact of stem borers in Louisiana, an urgent need exists to develop strategies for management. Currently, no IPM program is in place for stem borers in Louisiana rice and research has been initiated to develop an IPM program for these pests. The first objective of this research was focused on host plant resistance. For this …
Texasweed (Caperonia Palustris (L.) St. Hil.) Interference And Management In Drill-Seeded Rice, Rakesh K. Godara
Texasweed (Caperonia Palustris (L.) St. Hil.) Interference And Management In Drill-Seeded Rice, Rakesh K. Godara
LSU Doctoral Dissertations
Field research was conducted from 2006 to 2009 to study Texasweed [Caperonia palustris (L.) St. Hil.] interference and management in Cocodrie rice. Texasweed interference at 10 plants/m2 caused 24 to 31% rice yield reduction. The maximum possible yield loss was estimated to be 81%. Rice yield reduction was primarily due to a reduction in culms/m2 and filled grains per panicle. For maximum yield, Texasweed must be removed by two weeks after emergence and managed until permanent flood establishment. Shade had no effect on Texasweed emergence but significantly reduced growth and reproduction. At 100 days after emergence, 50, 70, and 90% …
Integrated Management Of Creeping Rivergrass In Rice, Sunny Lynn Bottoms
Integrated Management Of Creeping Rivergrass In Rice, Sunny Lynn Bottoms
LSU Doctoral Dissertations
Studies were conducted to evaluate growth and reproductive capabilities of creeping rivergrass in response to flood depth, burial depth, desiccation, herbicide programs and interference with rice. Seed production of a natural population of creeping rivergrass was 0.8 seeds per panicle. Germination was 45% and seedling vigor was poor. Flowers from surviving seedlings were male sterile. A 5 and 10 cm flood depth increased fresh weight, stolon length, and node production of creeping rivergrass compared with non-flooded plants. However, depths at 15 and 20 cm did not differ from no-flood; therefore permanent flooding should be delayed until rice can survive a …
Molecular, Statistical And Genetic Analyses Of Complex Agronomic Traits In Rice, Samuel Agbayani Ordonez Jr.
Molecular, Statistical And Genetic Analyses Of Complex Agronomic Traits In Rice, Samuel Agbayani Ordonez Jr.
LSU Doctoral Dissertations
Novel molecular and statistical approaches are needed for identification of DNA markers associated with complex traits in rice. The first research objective was to evaluate mixed-model and multiple regression approaches for their ability to identify molecular markers associated with complex traits in rice. A combined mixed model and multiple regression approach was optimal for selecting the smallest number of DNA markers associated with relatively high R2 values and for consistency with previous mapping studies. Support Vector Regression (SVR) was evaluated in the second research objective for the ability to generate high levels of accuracy and power for markers associated with …
Effects Of Simulated Drift Of Glyphosate, Imazethapyr, Glufosinate, And Imazamox To Non-Transgenic Rice, Justin Brian Hensley
Effects Of Simulated Drift Of Glyphosate, Imazethapyr, Glufosinate, And Imazamox To Non-Transgenic Rice, Justin Brian Hensley
LSU Doctoral Dissertations
Four studies were conducted at the LSU AgCenter Rice Research Station near Crowley, Louisiana to evaluate the effects of simulated herbicide drift on ‘Cocodrie’ rice. Herbicides were applied at 6.3 and 12.5% of the labeled usage rate of 863 g ae/ha of glyphosate, 70 g ai/ha of imazethapyr, 493 g ai/ha of glufosinate, and 44 g ai/ha of imazamox. Herbicides were applied to rice at the 1-tiller, panicle differentiation (PD), boot, and physiological maturity growth stages. Spray volume varied proportionally to herbicide dosage and was 15 L/ha for the 6.3% rate and 29 L/ha for the 12.5% rate using 234 …
Echinochloa Polystachya Management In Louisiana Rice, Roy Matthew Griffin
Echinochloa Polystachya Management In Louisiana Rice, Roy Matthew Griffin
LSU Doctoral Dissertations
E. polystachya introduced at stand densities (SD) of 10,000 through 70,000 stolon segments/ha produced 5.4 to 6 stolons/introduced segment; however, 130,000 through 520,000 SD produced 1.4 to 2.1 stolons per introduced segment indicating increased intra- and inter-specific competition. Stolon production was greater than 160,000 plants/ha with 30,000 through 520,000 SD. The 520,000 SD produced a total stolon length of 318 km/ha and no difference was observed for the 260,000 SD. Total node production was 290,000 nodes/ha with an average of 29 nodes/introduced segment in the 10,000 SD and 5.4 to 9.8 nodes/introduced segment with 70,000 or greater SD indicating greater …
Association Genetics For Agronomic Traits In Rice And Cloning Of Als Herbicide Resistant Genes From Coreopsis Tinctoria Nutt, Nengyi Zhang
Association Genetics For Agronomic Traits In Rice And Cloning Of Als Herbicide Resistant Genes From Coreopsis Tinctoria Nutt, Nengyi Zhang
LSU Doctoral Dissertations
We have evaluated the potential of discriminant analysis (DA) to detect candidate markers associated with twelve economically important traits in a large population of unrelated U.S. and Asian inbred lines of rice. Associated marker alleles detected by DA mapped within the same genetic intervals when compared with previous traditional QTL mapping experiments that evaluated progeny derived from various controlled crosses. New markers identified by DA suggest that the procedure can also uncover relevant genetic regions not possible by standard genetic tests. With the same dataset, we also compared different modern regression approaches for selecting molecular markers associated with the twelve …
Effect Of Plant Residue And Water Management Practices On Soil Redox Chemistry, Methane Emission, And Rice Productivity, Manoch Kongchum
Effect Of Plant Residue And Water Management Practices On Soil Redox Chemistry, Methane Emission, And Rice Productivity, Manoch Kongchum
LSU Doctoral Dissertations
Approximately 5 % of rice growing area in Louisiana experience poor seedling or stand development attributed to anaerobic decomposition of excess plant residue, which create strongly reducing or toxic soil conditions. This study investigated plant residue and flooding regime effects on soil properties as related to rice growth and seedling development. Field experiments were conducted at several commercial farms in Southwest Louisiana (which have experienced problem with rice stand development) to relate observed restricted rice growth to soil redox chemistry and other chemical and physical properties. Field experiments were also conducted at the Crowley Rice Research Station in which various …
Integration Of Management Tactics For The Rice Water Weevil Lissorhoptrus Oryzophilus Kuschel With Particular Emphasis On Use Of Plant Resistance (Tolerance), Li Zou
LSU Doctoral Dissertations
Studies were conducted to test the hypothesis, significant benefits can be achieved for the management of rice water weevil, Lissorhoptrus oryzophilus Kuschel, by the use of rice varieties with low levels of host plant resistance coupled with the judicious use of cultural practices and insecticides. Tolerant traits of a current commercial variety of rice, "Bengal", was manifested consistently over multiple years. Study on rice growth as effected by weevil injury showed that pruning of root systems by larvae of weevil resulted in a decrease in tiller number and shoot biomass of rice plants in the vegetative stage of growth. Yield …
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 …
Effects Of Submergence And Hypoxia On The Growth And Anatomy Of Rice (Oryza Sativa L.) Seedlings, Denise M. D'Abundo
Effects Of Submergence And Hypoxia On The Growth And Anatomy Of Rice (Oryza Sativa L.) Seedlings, Denise M. D'Abundo
LSU Doctoral Dissertations
Aerenchyma - a specialized tissue with abundant, interconnected gas spaces - facilitates oxygen transport from shoots to roots in many emergent wetland plants. The importance of oxygen transport to root elongation and aerenchyma development in rice (Oryza sativa L.) seedlings was demonstrated in this investigation. Germinated seeds of Lemont (a commercial cultivar) and red rice (an agricultural weed) were positioned at 4.5, 2.5, or 1.0 cm below the surface of aerated or hypoxic water to control the duration of leaf submergence and the availability of oxygen. Primary root and leaf lengths were measured daily. Aerenchyma was compared among emergent and …
A Game Theoretic Analysis Of U.S. Rice Exports Under Alternative Japanese And South Korean Policy Scenarios, Dae-Seob Lee
A Game Theoretic Analysis Of U.S. Rice Exports Under Alternative Japanese And South Korean Policy Scenarios, Dae-Seob Lee
LSU Doctoral Dissertations
As a result of the Uruguay Round (UR), the impact on the international rice market is profound. In addition, another round of the WTO trade negotiations has started and the impacts of potential policy changes on rice trade are unknown. The major U.S. benefit of the UR has been the access to the Japanese market. However, the U.S. share of this import market has been unstable and the share of Korean rice market is zero percent. Therefore, this study attempts to analyze the potential implication of U.S. rice exports to Japan and Korea. The Japanese and Korean rice economies as …