Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. Includes bibliographical references.

Thesis (M.S.)--Missouri State University, 2009. / "May 2009." Includes bibliographical references (leaves 12, 28-29, 39). Also available online.

Thesis (MSc)--Stellenbosch University, 2012. / Triticale is an amphidiploid that consists of wheat (A and B) and rye (R) genomes. This cereal is fast becoming important on a commercial basis and warrants further assessment for the better management and breeding of the hybrid. The assessment of the genetic diversity among the wheat and rye genomes within triticale can be obtained by using molecular markers developed in both donor genomes. Simple sequence repeats markers (SSRs) and amplified fragment length markers (AFLPs) have been previously used to assess the genetic diversity among triticale lines. SSRs are highly polymorphic markers that are abundant and which have been shown to be highly transferable between species in previous studies while AFLP markers are known to generate plenty of data as they cover so many loci. Thus, the aim of this study was to develop a marker system suitable to assess the genetic diversity and relationships of advanced breeding material (and cultivars) of the Stellenbosch University’s Plant Breeding Laboratory (SU-PBL). Therefore, both AFLP and SSR markers were initially analysed using eight triticale cultivars (with known pedigrees) to facilitate cultivar identification. Fourty-two AFLP primer combinations and 86 SSR markers were used to assess the genetic diversity among the Elite triticale cultivars. The AFLP primer combinations generated under average polymorphism information content (PIC) values. Furthermore, these markers generated neighbour-joining (NJ) and unweighted pair group method with arithmetic average (UPGMA) dendograms that displayed relationships that did not correspond with the available pedigree information. Therefore, this marker system was found not to be suitable. A set of 86 SSRs previously identified in both wheat and rye, was used to test the genetic diversity among the eight cultivars. The markers developed in wheat achieved 84% transferability while those developed in rye achieved 79.3% transferability. A subset of SSR markers was able to distinguish the cultivars, and correctly identify them by generating NJ and UPGMA dendograms that exhibited relationships that corroborated the available pedigree data. This panel of markers was therefore chosen as the most suitable for the assessment of the advanced breeding material. The panel of seven SSR markers was optimised for semi-automated analysis and was used to screen and detect the genetic diversity among 306 triticale entries in the F6, Senior and Elite phases of the SU-PBL triticale breeding programme. An average PIC value of 0.65 was detected and moderate genetic variation was observed. NJ and UPGMA dendograms generated showed no clear groupings. However, the panel of markers managed to accurately identify all cultivars within the breeding program. The marker panel developed in this study is being used to routinely distinguish among the advanced breeding material within the SU-PBL triticale breeding programme and as a tool in molecular-assisted backcross.

Fundação Araucária, CAPES / A jabuticabeira (Plinia sp.) é uma espécie frutífera nativa do centro-sul do Brasil, pertencente a família Myrtaceae. Embora apresente grande potencial de exploração econômica, ainda é uma fruteira típica de quintais e raras são as referências sobre dispersão, caracterização da divergência genética e sistema de reprodução. Estes aspectos são importantes para fomentar futuros trabalhos de melhoramento genético. Com o objetivo de melhor conhecer esta espécie, foram realizados observações e testes sobre a dispersão geográfica de jabuticabeiras nativas na região Sudoeste do Paraná e caracterização da divergência genética entre plantas nativas, assim como, sobre a caracterização morfológica, modo de reprodução, viabilidade do pólen e número cromossômico de genótipos cultivados de três espécies de jabuticabeira (P. cauliflora, P. jaboticaba e P. trunciflora). Na região Sudoeste do Paraná, as jabuticabeiras nativas se localizam sempre na parte mais alta da topossequência e a altura das plantas está relacionada com a altitude do local de ocorrência. Os solos dos locais de ocorrência são argilosos, fortemente ácidos e com baixa saturação de bases. Existem evidências sustentáveis de variabilidade genética entre jabuticabeiras nativas, principalmente entre diferentes locais de ocorrência. Destacam-se os genótipos CV5 e VT3, com alta divergência genética e caracteres agronômicos superiores. Há variabilidade de caracteres de folhas, flores e frutos entre genótipos das três espécies. O tamanho do pedúnculo do fruto pode servir para diferenciação entre as mesmas. A jabuticabeira necessita de agente polinizador, especialmente abelhas africanizadas (Apis mellifera) para que ocorra a fertilização das flores e fixação de frutos. O ácido bórico é necessário na constituição do meio de cultura para testes de germinação in vitro de pólen de jabuticabeira. A viabilidade do pólen é máxima após seis horas da antese, coincidindo com o período de maior visitação das abelhas. É possível a conservação do pólen de jabuticabeira por até 90 dias, desde que apresente alta germinação inicial (maior que 80%). O número cromossômico das três espécies de jabuticabeira parece ser 2n = 22. Entretanto, estas observações não são definitivas e novos estudos são necessários. / The jabuticabeira (Plinia sp.) is native fruit specie of central-south of Brazil, belonging to the Myrtaceae family. Although it has great economic potential exploit, is still a typical fruit for gardens and rare are the references on dispersion, characterization of genetic diversity and reproductive system. These aspects are important to encourage future work on breeding program. Aiming to better know this species, observations and tests were performed on the geographical dispersion of native jabuticaba trees of the southwest of Paraná, Brazil, and characterization of genetic divergence between native plants, as well on the morphological characterization, reproduction mode, pollen viability and the chromosome number of cultivated genotypes of three species of jabuticabeira (P. cauliflora, P. jaboticaba and P. trunciflora). In the Southwest region of Paraná, native jabuticabeiras were located always in the highest part of the toposequence and tree height is related to the altitude of ocurrence. The soils where jabuticabeira grows up are clay, strongly acidic (pH almost 4.0), and with low saturation of bases. There are genetic variability between native jabuticabeira, especially between different places of occurrence. Among them CV5 and VT3 genotypes, showed high genetic diversity and superior agronomic traits. There is variability of characters of leaves, flowers and fruits between genotypes of the three species. The size of the fruit stalk can be used to differentiate them. Jabuticabeira needs a polinizer, especially Africanized bees (Apis mellifera) for flower fertilization and fruit set. The boric acid is needed in making a standard media for testing in vitro germination of jabuticabeira pollen. The pollen viability is greater six hours after anthesis, coinciding with the period of increased bee visitation. It is possible the conservation of jabuticabeira pollen for up to 90 days, if it has high initial germination (greater than 80%). The chromosome number of the three jabuticabeira species seems to be 2n = 22. However, these observations are not definitive and further studies are needed.

Fundação Araucária, CAPES / A jabuticabeira (Plinia sp.) é uma espécie frutífera nativa do centro-sul do Brasil, pertencente a família Myrtaceae. Embora apresente grande potencial de exploração econômica, ainda é uma fruteira típica de quintais e raras são as referências sobre dispersão, caracterização da divergência genética e sistema de reprodução. Estes aspectos são importantes para fomentar futuros trabalhos de melhoramento genético. Com o objetivo de melhor conhecer esta espécie, foram realizados observações e testes sobre a dispersão geográfica de jabuticabeiras nativas na região Sudoeste do Paraná e caracterização da divergência genética entre plantas nativas, assim como, sobre a caracterização morfológica, modo de reprodução, viabilidade do pólen e número cromossômico de genótipos cultivados de três espécies de jabuticabeira (P. cauliflora, P. jaboticaba e P. trunciflora). Na região Sudoeste do Paraná, as jabuticabeiras nativas se localizam sempre na parte mais alta da topossequência e a altura das plantas está relacionada com a altitude do local de ocorrência. Os solos dos locais de ocorrência são argilosos, fortemente ácidos e com baixa saturação de bases. Existem evidências sustentáveis de variabilidade genética entre jabuticabeiras nativas, principalmente entre diferentes locais de ocorrência. Destacam-se os genótipos CV5 e VT3, com alta divergência genética e caracteres agronômicos superiores. Há variabilidade de caracteres de folhas, flores e frutos entre genótipos das três espécies. O tamanho do pedúnculo do fruto pode servir para diferenciação entre as mesmas. A jabuticabeira necessita de agente polinizador, especialmente abelhas africanizadas (Apis mellifera) para que ocorra a fertilização das flores e fixação de frutos. O ácido bórico é necessário na constituição do meio de cultura para testes de germinação in vitro de pólen de jabuticabeira. A viabilidade do pólen é máxima após seis horas da antese, coincidindo com o período de maior visitação das abelhas. É possível a conservação do pólen de jabuticabeira por até 90 dias, desde que apresente alta germinação inicial (maior que 80%). O número cromossômico das três espécies de jabuticabeira parece ser 2n = 22. Entretanto, estas observações não são definitivas e novos estudos são necessários. / The jabuticabeira (Plinia sp.) is native fruit specie of central-south of Brazil, belonging to the Myrtaceae family. Although it has great economic potential exploit, is still a typical fruit for gardens and rare are the references on dispersion, characterization of genetic diversity and reproductive system. These aspects are important to encourage future work on breeding program. Aiming to better know this species, observations and tests were performed on the geographical dispersion of native jabuticaba trees of the southwest of Paraná, Brazil, and characterization of genetic divergence between native plants, as well on the morphological characterization, reproduction mode, pollen viability and the chromosome number of cultivated genotypes of three species of jabuticabeira (P. cauliflora, P. jaboticaba and P. trunciflora). In the Southwest region of Paraná, native jabuticabeiras were located always in the highest part of the toposequence and tree height is related to the altitude of ocurrence. The soils where jabuticabeira grows up are clay, strongly acidic (pH almost 4.0), and with low saturation of bases. There are genetic variability between native jabuticabeira, especially between different places of occurrence. Among them CV5 and VT3 genotypes, showed high genetic diversity and superior agronomic traits. There is variability of characters of leaves, flowers and fruits between genotypes of the three species. The size of the fruit stalk can be used to differentiate them. Jabuticabeira needs a polinizer, especially Africanized bees (Apis mellifera) for flower fertilization and fruit set. The boric acid is needed in making a standard media for testing in vitro germination of jabuticabeira pollen. The pollen viability is greater six hours after anthesis, coinciding with the period of increased bee visitation. It is possible the conservation of jabuticabeira pollen for up to 90 days, if it has high initial germination (greater than 80%). The chromosome number of the three jabuticabeira species seems to be 2n = 22. However, these observations are not definitive and further studies are needed.

Many stress situations limit plant growth, resulting in crop production difficulties. Population growth, limited availability and over-utilization of arable land, and intolerant crop species have resulted in tremendous strain being placed on agriculturalists to produce enough to sustain the world's population. An understanding of the principles involved in plant resistance to environmental stress will enable scientists to harness these mechanisms to create stress-tolerant crop species, thus increasing crop production, and enabling the farming of previously unproductive land. This research project uses computational and bioinformatics techniques to explore the promoter regions of genes, encoding proteins that are up- or down-regulated in response to specific abiotic stresses, with the aim of identifying common patterns in the cis-elements governing the regulation of these abiotic stress responsive genes. An initial dataset of fifty known genes encoding for proteins reported to be up- or down-regulated in response to plant stresses that result in water-deficit at the cellular level viz. drought, low temperature, and salinity, were identified, and a postgreSQL database created to store relevant information pertaining to these genes and the proteins encoded by them. The genomic DNA was obtained where possible, and the promoter and intron regions identified. The Neural Network Promoter Prediction (NNPP) software package was used to predict the transcription start signal (TSS) and the promoter searching software tool, TESS (Transcription Element Search Software) used to identify known and user-defined cis-elements within the promoter regions of these genes. Currently available promoter prediction software analysis tools are reported to predict one promoter per kilobase of DNA, whilst functional promoters are thought to only occur one in 30-40 kilobases, which indicates that a large perccntage of predictions are likely to be false positives (pedersen et. al., 1999). NNPP was chosen as it was rated as the highest performing promoter prediction software tool by Fickett and Hatzigeorgiou (1997) in a thorough review of eukaryotic promoter prediction algorithms, however results were less than promising as very few predicted TSS were identified in the area 50 bps up- and downstream of the gene start site, where biologically functional TSSs are known to occur (Reese, 2000; Fickett and Hatzigeorgiou, 1997). TESS results seemed to support the hypothesis that drought, low-temperature and high salinity plant stress response proteins have similar as-elements in their promoter regions, and suggested links to various other gene regulation mechanisms viz. gibberellin-, light-, auxin- and development-regulated gene expression, highlighting the vast complexity of plant stress response processes. Although far from conclusive, results provide a valuable basis for future comparative promoter studies that will attempt to deduce possible common transcriptional initiation of abiotic stress response genes. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

Thesis (MSc. (Plant production)) -- University of Limpopo, 2016 / Seriphium plumosum is a declared indicator of bush encroachment, and poses a serious threat to the management of sustainable utilization in all grasslands. The successful invasiveness of S. plumosum is attributed to its competitive ability and high allelopathic potential. A trial was established at the University of Limpopo to investigate the interference between S. plumosum and four plant species, namely: Eragrostis curvula, E. tef, Panicum maximum and Lactuca sativa. Plant material of S. plumosum were collected and used to make infusions which were used on the receiver species. The infusion inhibited the germination of all the receiver species, and it was highly significant (P ≤ 0.01), compared to control treatments where no inhibition occurred. All receiver species were sensitive to roots and shoots infusions, but the effect of shoots infusion differed significantly (P ≤ 0.01) from those of roots infusion. All receiver species were sensitive to both summer and winter collected materials, but plant material collected in winter had a bigger effect (P ≤ 0.01) than plant material from summer. All receiver species were sensitive to both fresh and stored plant material, but inhibition effects were not statistically significantly different (P ≥ 0.05). All receiver species were sensitive to both fresh and stored soils collected in infested areas, but effects were not significantly different (P ≥ 0.05), while the effects of infested and un-infested soils differed significantly (P ≤ 0.01). All receiver species were sensitive to soils collected during summer and winter. Where infested soils were concerned, all receiver species were sensitive to infested soils, compared to control treatments where no effects occurred. Where stored infested soils were concerned, all receiver species were sensitive to both fresh and stored infested soils. It was concluded that both plant material of S. plumosum and soils from areas encroached by S. plumosum have a negative effect on seed germination of the four receiver species. Should a farmer control this species by means of cutting, it should be quickly removed to allow the gass to recover. The farmer must not expect quick recovery of grasses due to the presence of allelopathic substances in the soil. / Agri-seta

For more than half of the world’s population, rice (Oryza sativa L.), the most saltsensitive cereal, is a dietary staple. Soil salinity is a major constraint to rice production worldwide. Thus, to feed 9 billion people by 2050, we need to increase rice production while facing the challenges of rapid global environmental changes. To meet some of these challenges, there is a vital requirement to significantly increase rice production in salinized land and improve photosynthetic efficiency. Exposure of plants to soil salinity rapidly reduces their growth and transpiration rates (TRs) due to the ‘osmotic component’ of salt stress (sensu Munns and Tester), which is hypothesized to be related to sensing and signaling mechanisms. Over time, toxic concentrations of Na+ and Cl− accumulate in the cells of the shoot, known as the ‘ionic component’ of salt stress, which causes premature leaf senescence. Both osmotic and ionic components of salinity stress are likely to impact yield. Despite significant advances in our understanding of the ionic components of salinity tolerance, little is known about the early responses of plants to salinity stress. In my PhD project, the aim was to analyze naturally occurring variation in salinity tolerance of rice and identify key genes related to higher salinity tolerance using high-throughput phenomics and field trials. I used a forward genetics approach, with two rice diversity panels (indica and aus) and recently published sequencing data (McCouch et al., 2017). Indica and aus were phenotyped under controlled conditions, while the indica diversity panel was also further studied under field conditions for salinity tolerance. I also examined previously unexplored traits associated with salinity tolerance, in particular the effects of salinity on transpiration and transpiration use efficiency. The non-destructive high-throughput experiments conducted under controlled conditions gave insights into the understudied shoot ion-independent component of salinity tolerance. In parallel, the field experiments increased our understanding of the genetic control of further components of salinity tolerance, including the maintenance of yield under saline conditions. Importantly, this project also aimed to improve the current association methods of GWAS by exploring and testing novel Mixed Linear Models. One major benefit of this Ph.D. project was the development of a more holistic approach that recognizes the complexity of the genotype–phenotype interaction. The purpose of my work was to shed more light on the genetic mechanisms of salinity tolerance in rice and discover genes associated with traits contributing to higher photosynthetic activity under both controlled and field conditions. This will ultimately lead to further exploration of the genetic diversity present in the PRAY indica panel, in order to develop higher yielding rice varieties.

Call number: LD2668 .T4 1984 T68 / Master of Science

O conhecimento da associação entre plantas carnívoras e a comunidade bacteriana pode mostrar uma diversidade ainda não conhecida, além de proporcionar um melhor entendimento dos mecanismos envolvidos na interação de ambas. O objetivo deste trabalho foi avaliar a diversidade microbiana presente em utrículos de Utricularia foliosa através da análise de bibliotecas do gene 16S rRNA obtida por pirosequenciamento. Os resultados indicam que no ponto 1, Proteobacteria (58%), Firmicutes (11%), Cyanobacteria (11%), Acidobacteria (7%), Verrucomicrobia (5%), Actinobacteria (3%) Chlamidiae (2%) e Bacteroidetes (1%) foram os grupos dominantes. Já no ponto 2 houve uma maior presença de Eukaryota (51%), sendo que os grupos mais presentes foram Streptophyta (88%), Bacillariophyta (7%) e Chlorophyta (2%). A grande presença de algas encontradas pode estar relacionada à disponibilidade de nutrientes nos utrículos e gerar um acréscimo de carbono e nitrogênio à cadeia alimentar no interior da armadilha. / Knowledge of the association between carnivorous plants and the bacterial community can show a diversity not yet known, and provide a better understanding of the mechanisms involved in the interaction of both.The aim of this study was to evaluate the microbial diversity present in utricles of Utricularia foliosa and evaluate the effect of plant growth site in this diversity. For this the 16S rRNA gene library was sequenced by pyrosequencing (454-Roche). The results indicate that in point 1, the dominants groups were composed by Proteobacteria (58%), Firmicutes (11%), Cyanobacteria (11%), Acidobacteria (7%), Verrucomicrobia (5% ) Actinobacteria (3%) Chlamidiae (2%) and Bacteroidetes (1%), while in the point 2, Eukaryota (51%), such as Streptophyta (88%), Bacillariophyta (7%) and Chlorophyta (2%) were dominant. The large presence of algae inside the utricles may be related to the availability of nutrients and increase the Carbon and nitrogen level inside the traps, allowing the growth of the plant and also the microbial community in this structures.