Life Sciences Commons^™

Development And Characterization Of Rice Genotypes For Water Use Efficiency And Drought Resistance, Anuj Kumar

Graduate Theses and Dissertations

Rice, the second largest staple food crop, uses 30% of global fresh water to complete its life cycle worldwide. Water deficits worldwide have become a serious problem affecting rice growth and ultimately grain yield. To solve the water problem globally, improvement of water use efficiency (WUE) and other drought resistance (DR) traits in rice genotypes would be a useful strategy using advanced genomics tools. In this study, our objectives were to 1) analyze phenotypes of the USDA rice mini-core collection (URMC) for WUE and DR related traits, 2) correlate drought response phenes for physiological traits and grain yield in the …

The Effect Of Preflood Nitrogen And Flood Establishment Timing On Rice Development, Nitrogen Uptake And Grain Yield, Tyler Richmond

Graduate Theses and Dissertations

Urea-N fertilizer is typically applied at the 5-leaf stage to rice (Oryza sativa L.) grown in a dry-seeded, delayed-flood production system. How long the preflood-N can be delayed without adverse effects on yield potential is poorly understood. The research objective was to determine the effects of preflood-N application and flood establishment timing on aboveground-N content, 50% heading, yield components, and grain yield. Trials were established on silt loam soils at the Pine Tree Research Station (PTRS) and Rice Research and Extension Center (RREC) during 2015 and 2016. Urea-N was applied at 0, 45, 90, 135, and 180 kg N ha-1 …

Evaluation Of Provisia Rice In Arkansas Rice Production Systems, Zachary Lancaster

Graduate Theses and Dissertations

With the continued evolution of herbicide resistance, it is becoming more difficult to achieve adequate weed control in Arkansas rice production systems. Thus, new technologies are needed to combat these troublesome weeds. A new non-GMO, herbicide-resistant rice type is under development that is resistant to quizalofop, an acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicide that will allow for selective grass weed control in rice. With the commercialization of this technology by 2018, research was conducted to determine the best fit for quizalofop-resistant rice in current production systems. Experiments included evaluation of off-target movement of quizalofop, determination of plant-back risk from quizalofop …

Evaluation Of Insecticide Seed Treatments To Protect Rice (Oryza Sativa) Against Various Herbicides, Steven Michael Martin

Graduate Theses and Dissertations

The increase in herbicide-resistant weeds in Arkansas crop fields has led to the need for new herbicide modes of action for use in all crops. This need has led to the introduction of technologies that can be devastating to conventional rice crops. Field observation, noted that insecticide seed treatments used in rice could potentially reduce the effects of off-target movement of herbicides onto rice crops and possibly reduce the negative effects of some herbicides applied directly to rice. Research was conducted to determine if insecticide seed treatments could reduce the harmful effects of drift from imazethapyr and glyphosate onto conventional …

Evaluating Methods For Quantifying Evapotranspiration In Arkansas Rice, Colby Reavis

Graduate Theses and Dissertations

The goal of this study was to evaluate different methods for quantifying evapotranspiration (ET) in commercial rice fields using different irrigation regimes. The rice fields were located in south central Arkansas. The different irrigation regimes were alternate wetting and drying (AWD) and continuous flooding (CF). Alternate wetting and drying and conventional flooding estimates of ET were 602 mm and 570 mm, respectively, based on field observations using eddy covariance. Models used to estimate ET estimated values between 498 and 653 mm for the 2015 growing season. The Penman Monteith actual evapotranspiration model (PM AET) performed best when compared to the …

B. R. Wells Arkansas Rice Research Studies 2016, R. J. Norman, K.A. K. Moldenhauer

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Dissecting The Genetic Basis Of Salt Tolerance In Rice (Oryza Sativa), Malachy Thomas Campbell

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Excessive salt is a major factor limiting crop productivity. Rice is an important food crop worldwide, and provides a major source of calories for billions of people in tropical and subtropical developing countries. In many regions throughout Southeast Asia, rice is grown in low-lying coastal regions, which are prone to ingress by seawater. Rice is highly sensitive to salt stress, with mild salinity resulting in large reductions in yield. Improving salt tolerance in rice is essential for ensuring food security for many individuals throughput the developing world.

In this work, the overall goals were to characterize a diverse collection of …

Characterization Of Candidate Compound For Control Of Barnyardgrass And Other Troublesome Weeds In Rice, Michael Ryan Miller

Graduate Theses and Dissertations

Barnyardgrass remains one of the most difficult weeds to manage in rice. As herbicide resistance in this species, as well as others, continues to increase new control options are needed. Dow AgroSciences recently discovered and is developing a new herbicide for rice which is the primary focus of this research. Experiments were conducted to characterize this new herbicide for its use and effectiveness in midsouthern U.S. rice systems. The research conducted herein covers various aspects of herbicide characterization including: barnyardgrass dose response, accession testing, spectrum of control and tank-mix capability, application optimization, soil carryover and plant back determination, drift onto …

Seed Yield Prediction Models Of Four Common Moist-Soil Plant Species In Texas, Daniel P. Collins, Warren C. Conway, Corey D. Mason, Jeffrey W. Gunnels

Faculty Publications

Seed production by moist-soil plant species often varies within and among managed wetlands and on larger landscapes. Quantifying seed production of moist-soil plants can be used to evaluate wetland management strategies and estimate wetland energetic carrying capacity, specifically for waterfowl. In the past, direct estimation techniques were used, but due to excessive personnel and time costs, other indirect methods have been developed. Because indirect seed yield models do not exist for moist-soil plant species in east-central or coastal Texas, we developed direct and indirect methods to model seed production on regional managed wetlands. In September 2004 and 2005, we collected …

Transgenic Basmati Rice Transformed With The Xa21 Gene Shows Resistance Against Bacterial Leaf Blight, Zahid Mukhtar, Shahida Hasnain

Turkish Journal of Botany

Rice (Oryza sativa L.) cultivar Super Basmati was transformed with a cloned gene, Xa21, through particle bombardment method. Twenty-two plants were recovered from the selected calli. Initial screening through PCR confirmed the presence of the transgene in 21 plants. Southern analysis further confirmed the integration of the Xa21 gene into the genome of these transgenic plants. Analysis of the T1 generation revealed that both the hpt and Xa21 genes were successfully transmitted from the primary transformants to the progeny. Bioassays with two local isolates of bacterial leaf blight pathogen, Xanthomonas oryzae pv. oryzae (Xoo), showed that 14 transgenic lines were …

Estimating Yield Gaps At The Cropping System Level, Nicolas Guilpart, Patricio Grassini, Victor O. Sadras, Jagadish Timsina, Kenneth Cassman

Department of Agronomy and Horticulture: Faculty Publications

Yield gap analyses of individual crops have been used to estimate opportunities for increasing crop production at local to global scales, thus providing information crucial to food security. However, increases in crop production can also be achieved by improving cropping system yield through modification of spatial and temporal arrangement of individual crops. In this paper we define the cropping system yield potential as the output from the combination of crops that gives the highest energy yield per unit of land and time, and the cropping system yield gap as the difference between actual energy yield of an existing cropping system …

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.

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 …

Using An Active-Optical Sensor To Develop An Optimal Ndvi Dynamic Model For High-Yield Rice Production (Yangtze, China), Xiaojun Liu, Richard B. Ferguson, Hengbiao Zheng, Qiang Cao, Yongchao Tian, Weixing Cao, Yan Zhu

Department of Agronomy and Horticulture: Faculty Publications

The successful development of an optimal canopy vegetation index dynamic model for obtaining higher yield can offer a technical approach for real-time and nondestructive diagnosis of rice (Oryza sativa L) growth and nitrogen (N) nutrition status. In this study, multiple rice cultivars and N treatments of experimental plots were carried out to obtain: normalized difference vegetation index (NDVI), leaf area index (LAI), above-ground dry matter (DM), and grain yield (GY) data. The quantitative relationships between NDVI and these growth indices (e.g., LAI, DM and GY) were analyzed, showing positive correlations. Using the normalized modeling method, an appropriate NDVI simulation model …

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

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 …