Plant Breeding and Genetics Commons^™

Development And Characterization Of Wheat-Thinopyrum Junceiforme Chromosome Addition Lines, Dilkaran Singh

Electronic Theses and Dissertations

Production of wheat is challenged by dynamic biotic and abiotic stresses. Genetic improvement via alien gene transfer is an effective approach to tackle such challenges. Alien gene transfer played an important role in the history of wheat crop improvement. Sea wheatgrass (SWG; Thinopyrum junceiforme, 2n = 28, genomes J1J1J2J2) is a wild relative of wheat. In our previous work, we have developed a complete amphiploid between cultivated emmer and SWG and shown that SWG is resistant to wheat streak mosaic virus, Fusarium head blight and wheat stem sawflies (due to the solid stem) and tolerant to waterlogging, salinity, heat, and …

Identification And Characterization Of Stress Responsive Genes In Soybean And Sunflower, Surendra Neupane

Electronic Theses and Dissertations

Stress responsive genes encode proteins involved in plants’ response to abiotic and biotic stresses. Among such stress responsive proteins, proteins encoded by resistance genes (R genes) or nucleotide binding site-leucine-rich repeats (NBS-LRRs) and mitogen-activated protein kinases (MAPKs) are the major groups of proteins regulating biotic and abiotic stresses, respectively. Previous studies in Nepal’s lab at SDSU identified and characterized coiled coil (CC)-NBS-LRRs (CNLs), resistance to powdery mildew8 (RPW8)-NBS-LRRs (RNLs), NBS-LRR (NLs), and MAPK proteins in soybean. This study focuses on R and MAPK genes in the recently sequenced genome of sunflower as well as the toll-interleukin-1 receptor-like nucleotide-binding site leucine-rich …

Validation Of Candidate Loci For Maize Regrowability And Selection Of Near Isogenic Lines For The Loci, Tajbir Raihan

Electronic Theses and Dissertations

Developing perennial grain crops is an effective way for sustainable agriculture and it can be a tool for the betterment of the overall ecosystem. To understand how perenniality works in perennial species, we made a cross between Zea diploperennis and maize (Z. mays) inbred line B73. F1 hybrids produced from this cross were selfed to get the F2 population and later the F2 population underwent Genotyping-By- Sequencing (GBS) analysis. Based on the candidate loci identified on chromosome 2 and chromosome 7 from GBS, SNP-specific markers were developed from the candidate locus interval and used to genotype the F2 …

Yardwork: A Biography Of An Urban Place By Daniel Coleman, Vivian M. Hansen

The Goose

Review of Daniel Coleman's Yardwork: A Biography of an Urban Place.

Genetic Diversity In An Invasive Clonal Plant? A Historical And Contemporary Perspective, Elliot D. Weidow

LSU New Orleans Theses and Dissertations

Introduced populations of Eichhornia crassipes (Pontederiaceae) possess extremely low levels of genetic diversity due to severe bottleneck events and clonal reproduction. While populations elsewhere have been well studied, North American populations of E. crassipes remain understudied. We used Amplified Fragment Length Polymorphism markers to assess genetic diversity and population structure in North American E. crassipes populations. Patterns of diversity over the past fifty years were analyzed using herbarium specimens. Furthermore, we sampled populations across the Gulf Coast of the United States throughout a year to determine contemporary genetic diversity and assess potential seasonal effects. Genetic diversity was found to be …

Expression Of Carbohydrates Biosynthetic Genes In Developing Soybean Seeds, Jayden Rosen, Karen A. Hudson

The Summer Undergraduate Research Fellowship (SURF) Symposium

An essential part of livestock diets is soybean meal, which is a major source of protein, but which also consists of antinutritional carbohydrates. Antinutritional carbohydrates such as raffinose and stachyose lead to irritation to the gut for monogastric livestock as well as unhealthy weight gain. A major objective of soybean genetics is to reduce these antinutritional carbohydrates within the seed and increase the levels of good carbohydrates. This will lead to healthier livestock and better meat quality. To select genes potentially responsible for variation in carbohydrate levels in seeds, the expression of genes encoding several biosynthetic enzymes was measured during …

Impact Of Mid-Season Sulphur Deficiency On Wheat Nitrogen Metabolism And Biosynthesis Of Grain Protein, Zitong Yu, Angela Juhasz, Shahidul Islam, Dean Diepeveen, Jingjuan Zhang, Penghao Wang, Wujun Ma

Grain and Other Field Crops Research Articles

Wheat (Triticum aestivum) quality is mainly determined by grain storage protein compositions. Sulphur availability is essential for the biosynthesis of the main wheat storage proteins. In this study, the impact of different sulphur fertilizer regimes on a range of agronomically important traits and associated gene networks was studied. High-performance liquid chromatography was used to analyse the protein compositions of grains grown under four different sulphur treatments. Results revealed that sulphur supplementation had a significant effect on grain yield, harvest index, and storage protein compositions. Consequently, two comparative sulphur fertilizer treatments (0 and 30 kg ha−1 sulphur, with 50 …

Identification Of Qtl Modifying The Activity Of The Tcb1-S Locus And Characterization And Sequencing Of Two Plutonium-Beryllium Induced Reduced Gametophyte Transmission Mutants In Maize, Merritt Bryer Burch

Electronic Theses and Dissertations

This thesis is split into two independent projects both involving the male gametophyte generation of maize. The first project looks at how pollen interacts with the female gametophyte to reduce its transmission in cross-incompatible reactions controlled by the unilateral cross-incompatibility system, teosinte crossing barrier 1. The second project explores two plutonium-beryllium induced male gametophyte mutants and attempts to uncover their genetic basis.

Identification of QTL Modifying the Activity of the Tcb1-s Locus
Teosinte crossing barrier 1 (Tcb1) is a unilateral cross-incompatibility system present in maize that provides a pre-zygotic pistil barrier to plants carrying Tcb1-s (strong allele) from pollen …

Natural And Anthropogenic Drivers Of Tree Evolutionary Dynamics, Brandon M. Lind

Theses and Dissertations

Species of trees inhabit diverse and heterogeneous environments, and often play important ecological roles in such communities. As a result of their vast ecological breadth, trees have become adapted to various environmental pressures. In this dissertation I examine various environmental factors that drive evolutionary dynamics in threePinusspecies in California and Nevada, USA. In chapter two, I assess the role of management influence of thinning, fire, and their interaction on fine-scale gene flow within fire-suppressed populations of Pinus lambertiana, a historically dominant and ecologically important member of mixed-conifer forests of the Sierra Nevada, California. Here, I find evidence …

Effects Of Cultivar And Maternal Environment On Seed Quality In Vicia Sativa, Rong Li, Lijun Chen, Yanpei Wu, Rui Zhang, Carol C. Baskin, Jerry M. Baskin, Xiaowen Hu

Biology Faculty Publications

Production of high quality seeds is of fundamental importance for successful crop production. However, knowledge of the effects of increased temperature resulting from global warming on seed quality of alpine species is limited. We investigated the effect of maternal environment on seed quality of three cultivars of the leguminous forage species Vicia sativa, giving particular attention to temperature. Plants of each cultivar were grown at 1700 and 3000 m a.s.l., and mass, germination, electrical conductivity (EC) of leakage and longevity were determined for mature seeds. Seeds of all three cultivars produced at the low elevation had a significantly lower …

Cognition-Mediated Evolution Of Low-Quality Floral Nectars, Vladislav Nachev, Kai Petra Stich, Clemens Winter, Alan B. Bond, Alan Kamil, York Winter

Alan Bond Publications

Plants pollinated by hummingbirds or bats produce dilute nectars even though these animals prefer more concentrated sugar solutions. This mismatch is an unsolved evolutionary paradox. Here we show that lower quality, or more dilute, nectars evolve when the strength of preferring larger quantities or higher qualities of nectar diminishes as magnitudes of the physical stimuli increase. In a virtual evolution experiment conducted in the tropical rainforest, bats visited computer-automated flowers with simulated genomes that evolved relatively dilute nectars. Simulations replicated this evolution only when value functions, which relate the physical stimuli to subjective sensations, were nonlinear. Selection also depended on …

Molecular Diversity Of Foliar Fungal Endophytes In Relation To Defense Strategies And Disease In Whitebark Pine, Lorinda Bullington

Graduate Student Theses, Dissertations, & Professional Papers

An invasive fungal pathogen, Cronartium ribicola (the causative agent of white pine blister rust) infects and kills whitebark pine (Pinus albicaulis) throughout the western US. Blister rust has decreased whitebark pine populations by over 90% in some areas. Whitebark pine, a keystone species, has been proposed for listing under the Endangered Species Act in the U.S., and the loss of this conifer is predicted to have severe impacts on forest composition and function in high elevations. Hundreds of asymptomatic fungal species live inside whitebark pine tissue, and recent studies suggest that these fungi can influence the frequency and …

A Heavy Metal P-Type Atpase Oshma4 Prevents Copper Accumulation In Rice Grain, Xin-Yuan Huang, Fenglin Deng, Naoki Yamaji, Shannon R.M. Pinson, Miho Fujii-Kashino, John Danku, Alex Douglas, Mary Lou Guerinot, David Salt, Jian Feng Ma

Dartmouth Scholarship

Rice is a major source of calories and mineral nutrients for over half the world's human population. However, little is known in rice about the genetic basis of variation in accumulation of copper (Cu), an essential but potentially toxic nutrient. Here we identify OsHMA4 as the likely causal gene of a quantitative trait locus controlling Cu accumulation in rice grain. We provide evidence that OsHMA4 functions to sequester Cu into root vacuoles, limiting Cu accumulation in the grain. The difference in grain Cu accumulation is most likely attributed to a single amino acid substitution that leads to different OsHMA4 transport …

Are Local Filters Blind To Provenance? Ant Seed Predation Suppresses Exotic Plants More Than Natives, Dean Pearson, Nadia S. Icasatti, Jose L. Hierro, Benjamin J. Bird

Biological Sciences Faculty Publications

The question of whether species’ origins influence invasion outcomes has been a point of substantial debate in invasion ecology. Theoretically, colonization outcomes can be predicted based on how species’ traits interact with community filters, a process presumably blind to species’ origins. Yet, exotic plant introductions commonly result in monospecific plant densities not commonly seen in native assemblages, suggesting that exotic species may respond to community filters differently than natives. Here, we tested whether exotic and native species differed in their responses to a local community filter by examining how ant seed predation affected recruitment of eighteen native and exotic plant …

Novel Functional Roles For Perianthia And Seuss During Floral Organ Identity Specification, Floral Meristem Termination, And Gynoecial Development, April N. Wynn, Andrew A. Seaman, Ashley L. Jones, Robert G. Franks

Biological Sciences Research

The gynoecium is the female reproductive structure of angiosperm flowers. In Arabidopsis thaliana the gynoecium is composed of two carpels that are fused into a tube-like structure. As the gynoecial primordium arises from the floral meristem, a specialized meristematic structure, the carpel margin meristem (CMM), develops from portions of the medial gynoecial domain. The CMM is critical for reproductive competence because it gives rise to the ovules, the precursors of the seeds. Here we report a functional role for the transcription factor PERIANTHIA (PAN) in the development of the gynoecial medial domain and the formation of ovule primordia. This function …

Identifying Molecular Markers Associated With Salt And Boron Tolerance In Poplar Trees, Darshanpreet Gill, Nathan Follen, Davis W. Cheng, Kyan Salehi, Gary Banuelos, James P. Prince

STAR Program Research Presentations

Standard irrigation practices promote salt and boron accumulation in soils on the Westside of Central California. The build-up of these inorganic salts leads to the degradation of arable land and reduction of crop production. Different clones of poplar trees have been shown to grow in salt- and boron-contaminated soils, and in doing so, gradually remove significant amounts of these inorganic salts from the soil. In an effort to identify molecular markers linked with salt and boron tolerance in poplars, 31 PCR primer pairs have been designed based on candidate genes identified from the literature, and an additional 31 PCR primer …

Estudios Científicos En El Estado De Hidalgo Y Zonas Aledañas, Volumen Ii, Griselda Pulido-Flores, Scott Monks

Zea E-Books Collection

Los 16 capítulos que conforman este libro son una contribución al conocimiento de la biodiversidad y conservación de los recursos naturales en el estado de Hidalgo, México.

Se aborda el derecho de propiedad intelectual en la biodiversidad, citando algunos ejemplos de México. Así mismo, se presenta un estudio de la biodiversidad y distribución de la herpetofauna en cuatro tipos de vegetación. Desde el punto de vista de la helmintología se presentan dos estudios de los helmintos parásitos de vertebrados silvestres; con nuevos registros de hospederos y localidades de algunas especies de helmintos para Hidalgo. También, se aborda el uso de …

High Occurrence Of Functional New Chimeric Genes In Survey Of Rice Chromosome 3 Short Arm Genome Sequences, Chengjun Zhang, Jun Wang, Nicholas C. Marowsky, Manyuan Long, Rod A. Wing, Chuanzhu Fan

Biological Sciences Faculty Research Publications

In an effort to identify newly evolved genes in rice,we searched the genomes of Asian-cultivated rice Oryza sativa ssp. japonica and its wild progenitors, looking for lineage-specific genes. Using genome pairwise comparison of approximately 20-Mb DNA sequences from the chromosome 3 short arm (Chr3s) in six rice species, O. sativa, O. nivara, O. rufipogon, O. glaberrima, O. barthii, and O. punctata, combined with synonymous substitution rate tests and other evidence, we were able to identify potential recently duplicated genes, which evolved within the last 1 Myr. We identified 28 functional O. sativa genes, which …

Effects Of Reactive Oxygen Species On Life History Traits Of Caenorhabditis Elegans, Samson William Smith

Dissertations and Theses

Evolutionary life history theory predicts that tradeoffs among fitness-related phenotypes will occur as a result of resource limitations and/or physiological constraints. Such tradeoffs are defined as the cost(s) incurred on one component of fitness (e.g., reproduction) by the increased expression of another fitness-related trait (e.g., longevity). Only recently have researchers begun to investigate the mechanistic bases of life history tradeoffs. A recent proposal is that reactive oxygen species (ROS) have a central role in shaping life history traits and tradeoffs. Research on disparate animal taxa has highlighted strong correlations between oxidative stress resistance and fitness-related life history traits, for example. …

Generation Of Transgenic Medicago Sativa Overexpressing "Osmotin-Chitinase" Gene Chimera, Jahnavi Reddy Kancharla

Masters Theses & Specialist Projects

Medicago is widely used as a forage crop. It is often susceptible to various pathogenic infections and exhibits low growth in drought and extreme climatic conditions. In the current study, a strategy was developed for over-expressing an “Osmotin-Chitinase” gene chimera in transgenic Medicago that could potentially confer resistance to different biotic and abiotic stresses. Seed germination of several cultivars of Medicago (M. sativa ssp. sativa, M. sativa ssp. falcata, M. sativa ssp. caerulea, M. truncatula, and M. Rugosa) was tested to determine the cultivars with good germination rates. Among these, M. sativa ssp. sativa showed an …

Genetic Change Following Fire In Populations Of A Seed-Banking Perennial Plant, Rebecca W. Dolan, Pedro F. Quintana-Ascencio, Eric S. Menges

Scholarship and Professional Work - LAS

Disturbances such as fire have the potential to remove genetic variation, but seed banks may counter this loss by restoring alleles through a reservoir effect. We used allozyme analysis to characterize genetic change in two populations of the perennial Hypericum cumulicola, an endemic of the fire-prone Florida scrub. We assessed genetic variation before and 1, 2, and 3 years after fire that killed nearly all aboveground plants. Populations increased in size following fire, with most seedlings likely recruited from a persistent seed bank. Four of five loci were variable. Most alleles were present in low frequencies, but our large sample …

Nectar Secondary Compounds Affect Self-Pollen Transfer: Implications For Female And Male Reproduction, Rebecca E. Irwin, Lynn S. Adler

Dartmouth Scholarship

Pollen movement within and among plants affects inbreeding, plant fitness, and the spatial scale of genetic differentiation. Although a number of studies have assessed how plant and floral traits influence pollen movement via changes in pollinator behavior, few have explored how nectar chemical composition affects pollen transfer. As many as 55% of plants produce secondary compounds in their nectar, which is surprising given that nectar is typically thought to attract pollinators. We tested the hypothesis that nectar with secondary compounds may benefit plants by encouraging pollinators to leave plants after visiting only a few flowers, thus reducing self-pollen transfer. We …

The Complete Plastid Genome Sequence Of Welwitschia Mirabilis: An Unusually Compact Plastome With Accelerated Divergence Rates, Skip R. Mccoy, Jennifer V. Kuehl, Jeffrey L. Boore, Linda A. Raubeson

All Faculty Scholarship for the College of the Sciences

Background

Welwitschia mirabilis is the only extant member of the family Welwitschiaceae, one of three lineages of gnetophytes, an enigmatic group of gymnosperms variously allied with flowering plants or conifers. Limited sequence data and rapid divergence rates have precluded consensus on the evolutionary placement of gnetophytes based on molecular characters. Here we report on the first complete gnetophyte chloroplast genome sequence, from Welwitschia mirabilis, as well as analyses on divergence rates of protein-coding genes, comparisons of gene content and order, and phylogenetic implications.

Results

The chloroplast genome of Welwitschia mirabilis [GenBank: EU342371] is comprised of 119,726 base pairs and exhibits …

Sporophytic Inbreeding Depression In Mosses Occurs In A Species With Separate Sexes But Not In A Species With Combined Sexes, Philip J. Taylor, Sarah M. Eppley, Linley K. Jesson

Biology Faculty Publications and Presentations

Inbreeding depression is a critical factor countering the evolution of inbreeding and thus potentially shaping the evolution of plant sexual systems. Current theory predicts that inbreeding depression could have important evolutionary consequences, even in haploid-dominant organisms. To date, no data have been reported on inbreeding depression in moss species. Here, we present data on the magnitude of inbreeding depression in sporophytic traits of moss species with contrasting breeding systems. In eratodon purpureus (Ditrichaceae), a moss species with separate sexes, self-fertilizations between sibling gametophytes (intergametophytic selfing) significantly reduced fitness in two of four traits quantified, with seta length and capsule length …

Comparative Chloroplast Genomics: Analyses Including New Sequences From The Angiosperms Nuphar Advena And Ranunculus Macranthus, Linda A. Raubeson, Rhiannon Peery, Timothy W. Chumley, Chris Dziubek, H. Matthew Fourcade, Jeffrey L. Boore, Robert K. Jansen

All Faculty Scholarship for the College of the Sciences

Background

The number of completely sequenced plastid genomes available is growing rapidly. This array of sequences presents new opportunities to perform comparative analyses. In comparative studies, it is often useful to compare across wide phylogenetic spans and, within angiosperms, to include representatives from basally diverging lineages such as the genomes reported here: Nuphar advena (from a basal-most lineage) and Ranunculus macranthus (a basal eudicot). We report these two new plastid genome sequences and make comparisons (within angiosperms, seed plants, or all photosynthetic lineages) to evaluate features such as the status of ycf15 and ycf68 as protein coding genes, the distribution …

Contributions Of Heterosis And Epistasis To Hybrid Fitness, Mitchell B. Cruzan

Biology Faculty Publications and Presentations

Early-generation hybrid fitness is difficult to interpret because heterosis can obscure the effects of hybrid breakdown. We used controlled reciprocal crosses and common garden experiments to distinguish between effects of heterosis and nuclear and cytonuclear epistasis among morphotypes and advanced-generation hybrid derivative populations in the Piriqueta caroliniana (Turneraceae) plant complex. Seed germination, growth, and sexual reproduction of first-generation hybrids, inbred parental lines, and outbred parental lines were compared under field conditions. Average vegetative performance was greater for hybrids than for inbred lines, and firstseason growth was similar for hybrids and outbred parental lines. Hybrid survival surpassed that of inbred lines …

Patterns Of Fitness And Fluctuating Asymmetry Across A Broad Hybrid Zone, Mitchell B. Cruzan

Biology Faculty Publications and Presentations

We estimated levels of developmental instability in leaves, as indicated by fluctuating asymmetry (i.e., random deviations from perfect bilateral symmetry), across a broad hybrid zone between two taxa in the Piriqueta caroliniana complex. Previous studies have indicated that this hybrid zone was initiated in southern Florida and has expanded northward. We found that plants from the hybrid zone generally had higher levels of leaf developmental instability than plants from allopatric regions, but the increase in asymmetry was not substantial. Although it is usually assumed that developmental instability is associated with lower fitness, these Piriqueta hybrids from central Florida are similar …

Comparative Studies Of Evolutionary Responses To Light Environments In Arabidopsis, Massimo Pigliucci, Heidi Pollard, Mitchell B. Cruzan

Biology Faculty Publications and Presentations

In this article, we compare the reaction norms to foliage shade (changes in light quality, spatially fine-grained environmental variation) and photoperiod (day length, spatially coarse-grained environmental variation) in several haplotypes of Arabidopsis thaliana from Scandinavia. We found that both across-environment means and phenotypic plasticities evolved continuously and very rapidly within this group. Both character means and trait plasticities were highly integrated, in part as predicted by the adaptive plasticity hypothesis for response to foliage shade (the so-called shade-avoidance syndrome). We found that a significant but small fraction of the variance in across-treatment trait means and plasticities in response to one …

Genetic Relationships Between Two Rare Plant Species, Aliciella Caespitosa And A. Tenuis, And Their Putative Progenitor, A. Subnuda, Carrie L. Mccracken

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Isolated populations have potential to become new species that should have less genetic variation than their ancestors. Small populations are more likely to lose genetic variation, which is, thus, expected to be greater in ancestors. Aliciella caespitosa and A. tenuis, two endemic species, may be derived from small populations of A. subnuda, a widespread species. Chloroplast DNA sequences were used to test this hypothesis. Allozyme data were used to compare genetic variation and numbers of alleles. Chloroplast data do not support the proposed relationships between A. subnuda and the other two species. Allozyme data were not more variable …

Reproductive Biology Of Melilotus Officinalis (L.) Lam (Fabaceae: Papilionoideae): Morphology, Seed/Ovule Ratios And Ovule Abortion Patterns, Susan Lee Schouten

Dissertations and Theses

Melilotus officinalis, an introduced herbaceous species within the Papilionoideae, has a fixed ovule abortion pattern. In its primarily single-seeded, indehiscent fruits, with an average of 6.98 ovules/fruit, this species matured the basal-most ovule in 67.63% and the second basal-most ovule in 24.22% of the fruits studied. This pattern contrasts with other legumes studied, which abort the basal-most ovules or those at either end of the fruit. Workers propose interaction between two opposing gradients--that of maternal resources from the basal end of the fruit and of fertilization from the stylar end. Several lines of evidence indicate that all ovules are …