Botany Commons^™

Taxonomic Revision And Pollination Biology Of Orchid Genera Crepidium Blume And Dienia Lindl. (Malaxidinae, Orchidaceae) In Thailand, Anchalee Nuammee

Chulalongkorn University Theses and Dissertations (Chula ETD)

The terrestrial orchid Crepidium Blume and Dienia Lindl. in Thailand were enumerated by Gunnar Seidenfaden under Malaxis with key and drawings. Because of no species descriptions in publication, it is difficult to delimit species boundary. Moreover, recent discovery of new species results in unreliable assessment of species, therefore, the taxonomic revision of Crepidium and Dienia in Thailand should be carried out. The results indicated that the column and transversal callus on labellum are taxonomically important characters to delimit these two genera. In addition, morphological characters, i.e. stem and leaf morphology, labellum auricles, margins and number of teeth on distal margin …

Taxonomic Revision Of The Fern Family Athyriaceae In Thailand, Puttamon Pongkai

Chulalongkorn University Theses and Dissertations (Chula ETD)

The most up-to-date account of the Athyriaceae is in Flora of Thailand. This account includes seven genera, i.e. Athyrium, Anisocampium, Cornopteris, Deparia, Diplazium, Hypodematium and Kuniwatsukia. Previously, the taxonomic relationships among genera were ambiguous and not well understood. The existing keys and descriptions are uncertain and do not include some unknown taxa. This research aims to clarify the taxonomic status of this family and its genera based on morphological, anatomical, palynological and molecular data. The results indicated that the types and shapes of frond, scale types, sorus shapes, shapes of vascular bundle and ornamentation of spores are valuable characters for …

Evaluation Of Photosynthesis Process Under Drought-Stress Condition Of Chromosome Segment Substitution Line Populations With ‘Khao Dawk Mali 105’ Rice Genetic Background For Drought-Responsive Gene Identification And Characterization, Kansinee Hungsaprug

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to evaluate the photosynthesis-related parameters in chromosome segment substitution lines (CSSL), containing drought tolerant region from DH212 in a ‘KDML105’ genetic background. Screening at seedling stage indicated that CSSL4 was more tolerant to drought stress than ‘KDML105’ with the higher maximum quantum yield of Photosystem II (Fv/Fm). At vegetative stage, CSSL4 tended to have the higher level of light-saturated net photosynthetic rate (PNmax), stomatal conductance (gs), electron transport rate (ETR) and effective quantum yield of photosystem II photochemistry (FPSII), when compared to the ‘KDML105’ after 9 days of water withholding. Moreover, the flag leaves of CSSL4 and …

Low- Copy Nuclear Markers In Isoëtes (Isoëtaceae) Identified With Transcriptomes, Peter W. Schafran, Gabriel Johnson, W. Carl Taylor, Elizabeth A. Zimmer, Lytton J. Musselman

Biological Sciences Faculty Publications

PREMISE OF THE STUDY: Few genetic markers provide phylogenetic information in closely related species of Isoëtes (Isoëtaceae). We describe the development of primers for several putative low- copy nuclear markers to resolve the phylogeny of Isoëtes, particularly in the southeastern United States.

METHODS AND RESULTS: We identified regions of interest in Isoëtes transcriptomes based on low- copy genes in other plants. Primers were designed for these regions and tested with 16 taxa of Isoëtes and one species of Lycopodium. Parts of the pgiC, gapC, and IBR3 gene regions show phylogenetic signal within the North American and …

Drivers Of Post-Fire Vascular Plant Regeneration In The Conifer-Dominated Boreal Forest Of Southern Northwest Territories, Alison White

Theses and Dissertations (Comprehensive)

In recent years, climate warming has led to an increase in the severity and frequency of naturally occurring fires in boreal ecosystems globally. In 2014, an unprecedented 3.4 million hectares of boreal forest burned in the Northwest Territories (NWT). While much research has focused on post-fire succession of serotinous tree species such as Picea mariana (black spruce) and Pinus banksiana (jack pine), the understory community of vascular plants play an important role in ecosystem functioning but less is known about the response of this component of the system to changing fire regimes. Regeneration strategies such as the ability to resprout …

Evolution Of Floral Morphology And Symmetry In The Miconieae (Melastomataceae), Maria Gavrutenko

Dissertations and Theses

Analyses of evolution of floral morphology and symmetry broaden our understanding of the drivers of angiosperm diversification. Integrated within a flower, labile floral characters produce different phenotypes that promote variable interactions with pollinators. Thus, investigation of floral evolution may help infer potential historic transitions in pollinator modes and ecological pressures that generated present diversity. This study aims to explore morphological evolution of flowers in Miconieae, a species-rich Neotropical tribe within family Melastomataceae. Despite a constrained floral plan, Melastomataceae manage to achieve a variety of floral traits appealing to diverse pollinator types, with majority of the species requiring specialized “buzz pollination” …

Gene Expression Profiling Of Iron Deficiency Chlorosis Sensitive And Tolerant Soybean Indicates Key Roles For Phenylpropanoids Under Alkalinity Stress, Brian M. Waters, Keenan Amundsen, George L. Graef

Department of Agronomy and Horticulture: Faculty Publications

Alkaline soils comprise 30% of the earth and have low plant-available iron (Fe) concentration, and can cause iron deficiency chlorosis (IDC). IDC causes soybean yield losses of $260 million annually. However, it is not known whether molecular responses to IDC are equivalent to responses to low iron supply. IDC tolerant and sensitive soybean lines provide a contrast to identify specific factors associated with IDC.We used RNA-seq to compare gene expression under combinations of normal pH (5.7) or alkaline pH (7.7, imposed by 2.5mM bicarbonate, or pH 8.2 imposed by 5mM bicarbonate) and normal (25μM) or low (1μM) iron conditions from …

A Transcriptome‑Snp‑Derived Linkage Map Of Apios Americana (Potato Bean) Provides Insights About Genome Re‑Organization And Synteny Conservation In The Phaseoloid Legumes, Jugpreet Singh, Scott R. Kalberer, Vikas Belamkar, Teshale Assefa, Matthew N. Nelson, Andrew D. Farmer, William J. Blackmon, Steven B. Cannon

Department of Agronomy and Horticulture: Faculty Publications

Apios (Apios americana; “apios”), a tuberous perennial legume in the Phaseoleae tribe, was widely used as a food by Native Americans. Work in the last 40 years has led to several improved breeding lines. Aspects of the pollination biology (complex floral structure and tripping mechanism) have made controlled crosses difficult, and the previous reports indicated that the plant is likely primarily an outcrosser. We used a pseudo-testcross strategy to construct a genetic map specific to the maternal parent. The map was built using single-nucleotide polymorphism markers identified by comparing the expressed sequences of individuals in the mapping population …

Enhancing Resolution Of Natural Methylome Reprogramming Behavior In Plants, Robersy Sanchez, Xiaodong Yang, Hardik Kundariya, Jose R. Barreras, Yashitola Wamboldt, Sally A. Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

We have developed a novel methylome analysis procedure, Methyl-IT, based on information thermodynamics and signal detection. Methylation analysis involves a signal detection problem, and the method was designed to discriminate methylation regulatory signal from background noise induced by thermal fluctuations. Comparison with three commonly used programs and various available datasets to furnish a comparative measure of resolution by each method is included. To confirm results, methylation analysis was integrated with RNAseq and network enrichment analyses. Methyl-IT enhances resolution of genome methylation behavior to reveal network-associated responses, offering resolution of gene pathway influences not attainable with previous methods.

Prospects For Increasing Sugarcane And Bioethanol Production On Existing Crop Area In Brazil, Fábio R. Marin, Geraldo B. Martha Jr., Kenneth Cassman, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

This article assesses sugarcane yield gaps (YG) in Brazil to determine the degree to which production can be increased without land expansion. In our scenario assessments, we evaluated how much of the projected sugarcane demand to 2024 (for both sugar and bioethanol) can be satisfied through YG closure. The current national average yield is 62% of yield potential estimated for rainfed conditions (i.e., a YG of 38%). Continuing the historical rate of yield gain is not sufficient to meet the projected demand without an area expansion by 5% and 45% for lowand high-demand scenarios, respectively. Closing the exploitable YG to …

Biomass Yield Of Warm-Season Grasses Affected By Nitrogen And Harvest Management, Chamara S. Weerasekara, Newell R. Kitchen, Shibu Jose, Peter P. Motavalli, Sougata Bardhan, Robert B. Mitchell

Department of Agronomy and Horticulture: Faculty Publications

Native perennial warm-season grasses (NPWSG) have drawn interest as bioenergy feedstocks due to their high productivity with minimal amounts of inputs under a wide range of environments. Nitrogen fertility and harvest timing are critical management practices when optimizing biomass yield of NPWSG. Our objective was to quantify the impact of N fertilizer rate and timing in combination with harvest timing and frequency on NPWSG yield. Research was conducted in 2014 and 2015 on four field-plot locations in Missouri. The experiment was a split-plot design with three replications where N rate and harvest timing were the main and sub-plot treatments, respectively. …

Can Bangladesh Produce Enough Cereals To Meet Future Demand?, J. Timsina, J. Wolf, N. Guilpart, L G. J. Van Bussel, P. Grassini, J. Van Wart, A. Hossain, H. Rashid, S. Islam, M. K. Van Ittersum

Department of Agronomy and Horticulture: Faculty Publications

Bangladesh faces huge challenges in achieving food security due to its high population, diet changes, and limited room for expanding cropland and cropping intensity. The objective of this study is to assess the degree to which Bangladesh can be self-sufficient in terms of domestic maize, rice and wheat production by the years 2030 and 2050 by closing the existing gap (Yg) between yield potential (Yp) and actual farm yield (Ya), accounting for possible changes in cropland area. Yield potential and yield gaps were calculated for the three crops using well-validated crop models and site-specific weather,management and soil data, and upscaled …

Sifting And Winnowing: Analysis Of Farmer Field Data For Soybean In The Us North-Central Region, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Patricio Grassini, Adam C. Roth, Shaun N. Casteel, Ignacio A. Ciampitti, Hans J. Kandel, Peter M. Kyveryga, Mark A. Licht, Laura E. Lindsey, Daren S. Mueller, Emerson D. Nafziger, Seth L. Naeve, Jordan Stanley, Michael J. Staton, Shawn P. Conley

Department of Agronomy and Horticulture: Faculty Publications

Field trials are commonly used to estimate the effects of different factors on crop yields. In the present study, we followed an alternative approach to identify factors that explain field-to-field yield variation, which consisted of farmer survey data, a spatial framework, and multiple statistical procedures. This approach was used to identify management factors with strongest association with on-farm soybean yield variation in the US North Central (NC) region. Field survey data, including yield and management information, were collected over two crop growing seasons (2014 and 2015) from rainfed and irrigated soybean fields (total of 3568 field-year observations). Fields were grouped …

Genome-Wide Association Study For Identification And Validation Of Novel Snp Markers For Sr6 Stem Rust Resistance Gene In Bread Wheat, Amira M. I. Mourad, Ahmed Sallam, Vikas Belamkar, Stephen N. Wegulo, Robert Bowden, Yue Jin, Ezzat Mahdy, Bahy Bakheit, Atif A. El-Wafaa, Jesse Poland, Peter S. Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Stem rust (caused by Puccinia graminis f. sp. tritici Erikss. & E. Henn.), is a major disease in wheat (Triticum aestivium L.). However, in recent years it occurs rarely in Nebraska due to weather and the effective selection and gene pyramiding of resistance genes. To understand the genetic basis of stem rust resistance in Nebraska winter wheat, we applied genome-wide association study (GWAS) on a set of 270 winter wheat genotypes (A-set). Genotyping was carried out using genotyping-by-sequencing and ~35,000 high-quality SNPs were identified. The tested genotypes were evaluated for their resistance to the common stem rust race in …

Mapping Rootable Depth And Root Zone Plant-Available Water Holding Capacity Of The Soil Of Sub-Saharan Africa, John G. B. Leenaars, Lieven Claessens, Gerard B. M. Heuvelink, Tom Hengl, Maria Ruiperez Gonzalez, Lenny G. J. Van Bussel, Nicolas Guilpart, Haishun Yang, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

In rainfed crop production, root zone plant-available water holding capacity (RZ-PAWHC) of the soil has a large influence on crop growth and the yield response to management inputs such as improved seeds and fertilisers. However, data are lacking for this parameter in sub-Saharan Africa (SSA). This study produced the first spatially explicit, coherent and complete maps of the rootable depth and RZ-PAWHC of soil in SSA. We compiled georeferenced data from 28,000 soil profiles from SSA, which were used as input for digital soil mapping (DSM) techniques to produce soil property maps of SSA. Based on these soil properties, we …

Crop Residue Harvest Impacts Wind Erodibility And Simulated Soil Loss In The Central Great Plains, Yuxin He, Deann R. Presley, John Tatarko, Humberto Blanco-Canqui

Department of Agronomy and Horticulture: Faculty Publications

Crop residue removal can affect the susceptibility to soil wind erosion in climates such as those of the Central Great Plains, United States. Six on-farm trials were conducted in Kansas from 2011 to 2013 to determine the effects of winter wheat (Triticum aestivum L.), corn (Zea mays L.), and grain sorghum (Sorghum bicolor (L.) Moench), residue removal at 0, 25, 50, 75, and 100% of initial height on soil wind erosion parameters. Those parameters include soil surface random roughness (RR), and wind erodible fraction (EF; aggregates -¹ for three hours. Threshold wind velocity required to initiate …

Genetic Diversity And Population Structure Of F3:6 Nebraska Winter Wheat Genotypes Using Genotyping-By-Sequencing, Shamseldeen Eltaher, Ahmed Sallam, Vikas Belamkar, Hamdy A. Emara, Ahmed A. Nower, Khaled F. M. Salem, Jesse Poland, Peter S. Baenziger

Department of Agronomy and Horticulture: Faculty Publications

The availability of information on the genetic diversity and population structure in wheat (Triticum aestivum L.) breeding lines will help wheat breeders to better use their genetic resources and manage genetic variation in their breeding program. The recent advances in sequencing technology provide the opportunity to identify tens or hundreds of thousands of single nucleotide polymorphism (SNPs) in large genome species (e.g., wheat). These SNPs can be utilized for understanding genetic diversity and performing genome wide association studies (GWAS) for complex traits. In this study, the genetic diversity and population structure were investigated in a set of 230 genotypes …

Lowland Rice Nutrient Responses For The Guinea And Sudan Savannas Of Nigeria, Christogonus K. Daudu, Enemona M. Ugbaje, Eunice Y. Oyinlola, Bitrus D. Tarfa, Adamu A. Yakubu, Ishaku Y. Amapu, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

Yield response of irrigated lowland rice (Oryza sativa L.) to nutrient application was determined to improve the information base for fertilizer use in the Sudan and Southern Guinea Savannas of Nigeria. Economically optimal rates (EOR) and agronomic efficiency (AE) were determined. Five N levels and four levels each P, K, and Zn were evaluated with two varieties at two locations. Nitrogen effects varied by variety and location but mean paddy yield with 0 kg ha^–1 N was 3.4 Mg ha^–1 and was increased by 1.3 Mg ha^–1 with 40 kg ha^–1 N. The mean EOR …

Impaired Phloem Loading In Zmsweet13a,B,C Sucrose Transporter Triple Knock-Out Mutants In Zea Mays, Margaret Bezrutczyk, Thomas Hartwig, Marc Horschman, Si Nian Char, Jinliang Yang, Bing Yang, Wolf B. Frommer, Davide Sosso

Department of Agronomy and Horticulture: Faculty Publications

Crop yield is critical for human nutrition, yet the underlying machinery that ultimately determines yield potential is still not understood. Crop productivity under ideal conditions is determined by the efficiency with which plants intercept light, convert it into chemical energy, translocate photosynthates and convert these to storage products in harvestable organs (Zhu et al., 2010). In many crops, sucrose is the primary form for translocation inside the conduit (i.e. the phloem). A combination of SWEETmediated efflux from phloem parenchyma and subsequent secondary active sucrose import by SUT sucrose/H+ symporters is thought to create the driving force for pressure gradient-driven …

Can Bangladesh Produce Enough Cereals To Meet Future Demand?, J. Timsina, J. Wolf, N. Guilpart, L.G.J. Van Bussel, P. Grassini, J. Van Wart, A. Hossain, H. Rashid, S. Islam, M.K. Van Ittersum

Department of Agronomy and Horticulture: Faculty Publications

Bangladesh faces huge challenges in achieving food security due to its high population, diet changes, and limited room for expanding cropland and cropping intensity. The objective of this study is to assess the degree to which Bangladesh can be self-sufficient in terms of domestic maize, rice and wheat production by the years 2030 and 2050 by closing the existing gap (Yg) between yield potential (Yp) and actual farm yield (Ya), accounting for possible changes in cropland area. Yield potential and yield gaps were calculated for the three crops using well-validated crop models and site-specific weather,management and soil data, and upscaled …