The prospect of integrating transgenic eucalypts with conventional breeding programmes is of value to the Plantation Forestry and Forest Products Industries. However, significant progress in this regard has still to be reported, one constraint is the lack of appropriate high yielding regeneration culture methods for clonal material. Such was the main aim of the present study. The strategy was to develop a suitable protocol using in vitro shoots of an E. grandis x E. urophy/la clone (GU185) and thereafter to test its applicability to other clones. Explants from greenhouseestablished cuttings provided the in vitro shoots, which were multiplied via axillary bud proliferation either on semi-solid medium or using a RIT A system. To determine the best conditions for callus and shoot regeneration, parameters such as vessels (petri dishes and tubes) and types and levels of plant growth regulators were tested. The best callus production (100%) and shoot regeneration (78.9 - 100% callus with shoots) for GU185 occurred on MS, 30 g rl sucrose, 4 g rl Gelrite, 5 mg rl IAA and 0.25 mg rl BAP. Parameters tested to identify the most suitable explants for indirect organogenesis were the age of parent plants, different systems to generate in vitro shoots, elongation status of explants, 1 sI and 2nd generation in vitro shoots and the use of hyperhydric shoots. Of these, the most suitable explants for indirect organogenesis were shoots from axillary bud multiplication of 3-month-old parent plants using the semi-solid system (33 shoots/dish). Up to 90% rooting was achieved on 1f4 MS (Murashige and Skoog, 1962), 15 g rl sucrose, 0.1 mg rl biotin, 0.1 mg rl calcium pantothenate, 4 g rl Gelrite and mA. The highest rooting was obtained when regenerated shoots were first multiplied and then placed on medium without plant growth regulators for one week, before transfer to root induction medium containing 0.1 - 0.5 mg rl mA. Acclimatization success was 95% when rooted shoots were placed in pots with a rooting mix (2 perlite: 1 coir) enclosed in plastic bags and the humidity was gradually reduced over four weeks. The developed indirect organogenesis protocol appeared to have a broad general application, although the tested clones exhibited a genotype-dependent response, with GU180, GUI77 and TAG31 producing fewer shoots (9, 6 and 7 shoots/dish) than ZG14 and GU185 (24 and 18 shoots/dish). Similarly high levels of rooting were obtained for TAG3l (93.8%) and ZG14 (90%) and for hardening-off (90.7% for TAG31 and 91.4% for ZG14). / Thesis (M.Sc.)-University of KwaZulu-Natal, 2004.

The seeds of Trichilia dregeana, Trichilia emetica, Podocarpus henkelii and Syzygium cuminii display the characteristics typical of recalcitrant seeds. It is the phenomena of ongoing metabolic activity and desiccation sensitivity that render them unsuitable for storage by the conventional methods used for orthodox seeds. Investigations on the storage responses of 'sub-imbibed' (partially dried) and fully hydrated seeds of all four species were carried out to study the effects of partial drying on viability and subsequent storage lifespan; i.e. to assess whether 'sub-imbibed' storage is feasible for these species. The outcome of this investigation was proposed to contribute to the resolution of the argument that storing recalcitrant seeds at lowered water contents might extend their longevity; i.e. storage at a relatively high water content but below the fully hydrated level, might prevent germination but would not be sufficient to be injurious to the seed. Seeds of T. dregeana, T. emetica, P. henkelii and S. cuminii were dried to various target moisture contents (which were determined for each species in the initial drying experiment) and then subjected to storage for 3-22 weeks at 6, 16 and 25°C (in sealed containers). In parallel, seeds of each species were stored at the shedding water content. The seeds were periodically removed for sampling, and assessed for water content, germination, respiration, electrolyte leakage and microscopical features. Storage temperature appeared to affect viability of seeds of T. emetica and T. dregeana which displayed characteristics of chilling sensitivity. Storage at 6°C was detrimental (when compared with seeds stored under the same conditions at 16 and 25°C), but regardless of whether the seeds were undried or partially dried prior to storage. The seeds of P. henkelii did not demonstrate chilling sensitivity, the viability not being compromised at 6°C compared with those seeds stored at 16 and 25°C. Syzygium cuminii seeds were not subject to storage at 6°C because previous work indicated that they would be chilling-sensitive. Storage of 'sub-imbibed' seeds of T. dregeana, T. emetica, P. henkelii and Syzygium cuminii does not to confer any benefit over seeds stored in the fully hydrated state; rather it appears to be deleterious to seed survival during storage. This was apparent from the assessment of viability, electrolyte leakage and respiration. Vigour and viability of the 'sub-imbibed' seeds of all species declined more rapidly than the fully hydrated seeds. The only exception was P. henkelii seeds stored at 25°C, the fully hydrated seeds showed no survival after 11 weeks in storage, while 88% of the 'sub-imbibed' seeds survived this period. These results were, however, attributed to the proliferation of fungi on the fully hydrated seeds at 25°C. Although ultrastructural observations were made only on the T. emetica seeds, it was apparent that the cells from the 'sub-imbibed' seeds (after storage at 16 and 25°C) showed extensive degradation, with the intra-cellular components being largely unrecognisable. The cells from the seeds stored in the fully hydrated condition at 16 and 25°C maintained integrity and appeared metabolically active. In keeping with the suggestion that T. emetica seeds are chilling sensitive, the ultrastructure of the cells from both the 'sub-imbibed' and fully hydrated seeds showed deteriorative changes. All the results of the present study indicated that storage in the 'sub-imbibed' state is deleterious to seed survival. It is apparent that the removal of water, however small a proportion, accelerates seed deterioration during storage. Thus 'sub-imbibed' storage has no practical application for the storage of recalcitrant seeds. / Thesis (M.Sc)-University of KwaZulu-Natal, 2007.

The ogu-INRA cytoplasmic male sterility (CMS) system is the global leader for the development of high quality hybrid canola and high erucic acid rapeseed (HEAR) cultivars of oilseed rape (Brassica napus L.). The largest challenge for plant breeders using this system is the development of high quality restorer lines (R-lines) due to tight linkage of the radish (Raphanus sativus L.) derived restorer gene PPR-B and elevated seed glucosinolate concentration. The purpose of this study was to identify improved quality restorer lines for hybrid cultivar development through both field studies and molecular marker development. In the first study 67 R-lines of different genetic backgrounds were screened over the course of two growing seasons and lines with significantly reduced glucosinolate concentration were identified. In the second study a new sequence characterized amplified region (SCAR) marker was successfully developed for the rapid screening of selections for the ogu-INRA CMS restorer gene PPR-B.

The ogu-INRA cytoplasmic male sterility (CMS) system is the global leader for the development of high quality hybrid canola and high erucic acid rapeseed (HEAR) cultivars of oilseed rape (Brassica napus L.). The largest challenge for plant breeders using this system is the development of high quality restorer lines (R-lines) due to tight linkage of the radish (Raphanus sativus L.) derived restorer gene PPR-B and elevated seed glucosinolate concentration. The purpose of this study was to identify improved quality restorer lines for hybrid cultivar development through both field studies and molecular marker development. In the first study 67 R-lines of different genetic backgrounds were screened over the course of two growing seasons and lines with significantly reduced glucosinolate concentration were identified. In the second study a new sequence characterized amplified region (SCAR) marker was successfully developed for the rapid screening of selections for the ogu-INRA CMS restorer gene PPR-B.

Photocopy of typescript / v, 177 leaves, 6 leaves of plates : ill. (part col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.) Dept. of Agronomy, University of Adelaide, 1981

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:32:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-19Bitstream added on 2014-06-13T19:02:35Z : No. of bitstreams: 1 correa_lc_dr_botib.pdf: 1179525 bytes, checksum: beffa33d099cc5e0f66952e183424a29 (MD5) / A cultura da goiabeira ocupa importante espaço no agronegócio do país, um dos maiores produtores mundiais de goiaba. O araçazeiro, nativo do Brasil, embora não apresente a mesma importância econômica da goiaba, tem sido explorado em algumas regiões como alternativa de plantio devido à boa aceitação do seu fruto e também por apresentar características de interesse comercial e social. Dentre as características compartilhadas por goiabas e araçás estão a diversidade de uso, desde o consumo in natura até diferentes formas processadas, e a riqueza em nutrientes e em compostos fenólicos. Este trabalho visou à caracterização química e bioquímica de frutos de araçazeiros e goiabeiras do banco ativo de germoplasma (BAG) da Embrapa Semiárido, provenientes de diferentes regiões do Brasil, bem como a caracterização genética de parte dos acessos. Foram determinados os teores de açúcares, proteínas, sólidos solúveis, acidez titulável, “ratio” e umidade, além dos minerais: cálcio, magnésio, ferro, fósforo e potássio. Foram também analisados os antioxidantes: ácido ascórbico, fenóis totais, flavonóides totais, licopeno e β-caroteno, bem como a atividade antioxidante. Para a caracterização genética,, utilizou-se o marcador molecular AFLP (Amplified Fragment Length Polymorphism). Frutos de cinco acessos de goiabeira provenientes do Maranhão (G01MA, G12MA, G14MA, G16MA e G20MA), e dos acessos A08MA, A42PE, A45PE, A80RO e A100AM, de araçazeiros, se destacaram nas avaliações bioquímicas por apresentarem, no conjunto, os maiores teores de sólidos solúveis, açúcares, proteínas e minerais, além de estarem entre aqueles com menores teores de acidez titulável, no caso das goiabas, e maiores no caso dos araçás. Quanto aos antioxidantes, verificou-se que goiabas e araçás são ricos em compostos fenólicos, os quais apresentaram forte correlação... / The culture of guava has an important position in the agribusiness in the country, one of the largest producers of guava of the world. Brazilian guava tree, native of Brazil, although not present the same economic importance of guava has been explored in some regions as an alternative planting due to the high acceptance of its fruit and also present characteristics of commercial and social interest. The diversity of use, since the fresh market to different forms processed forms, and wealth of nutrients and phenolic compounds are among the characteristics shared by guavas and Brazilian guava. This work aimed at the chemical and biochemical characterization of Brazilian guava and guava fruit of the active germplasm bank (AGB) of Embrapa Semiarid, from different regions of Brazil and the genetic characterization of some accessions. The levels of sugars, proteins, soluble solids, titratable acidity, ratio and moisture, and minerals calcium, magnesium, iron, phosphorus and potassium were analyzed. There were also analyzed antioxidants: Ascorbic acid, total phenols, total flavonoids, lycopene and β-carotene, besides antioxidant activity. For the genetic characterization, was used the molecular marker AFLP (Amplified Fragment Length Polymorphism). Fruits of five accessions of guava from Maranhão state (G01MA, G12MA, G14MA, G16MA and G20MA), and the accessions A08MA, A42PE, A45PE, A80RO and A100AM of Brazilian guava highlighted in the biochemical assessment by presenting, in general, the larger soluble solids, sugars, proteins and minerals, and are among those with lower levels of acidity, in the case of guavas, and higher in the case of Brazilian guava. As for antioxidants, it was found that guavas and Brazilian guavas are rich in phenolic compounds, which showed strong correlation with antioxidant activity, showing be your main contributor. It was also observed that part of accesses... (Complete abstract click electronic access below)

Barley is one of the world's most important food and feed crops. It is adapted to a wide range of environments. According to Harlan and Martini (1936) barley is grown from north of the Artic Circle to the sands of the Sahara, and from the slopes of Mt. Everest to the lower delta of the Nile. Considerable progress has been made in its improvement through plant breeding. Barley is one of the best cultivated crop plants for use in genetic studies. It is a diploid plant from the family Gramineae with seven pairs of chromosomes. The cultivated species are interfertile and have a large number of readily distinguishable genetic characters. Approximately 370 characters are recognized (Nilan, 1964). Many of Barley's genes have been mapped and assigned to one of the seven chromosomes. Linkage groups in barley have been designated in a number of ways. A Roman numeral was used extensively in the earlier studies to identify each linkage group. More recently an Arabic number system has been used. This system was adopted by the Fourth Annual Barley Research Worker's Conference and will be followed in this study. The study involves 24 contrasting factors and was undertaken to determine the location of certain genes already reported in specific linkage groups and, if possible, to assign several previously unassigned genes to linkage groups. Of the 24 factor pairs studied, six have not yet been assigned to a chromosome. The inheritance and linkage associations of these unassigned genes receive major emphasis in this study.

With over 300,000 plant species on the planet and more than 90% of them relying on pollen for reproduction, palynology, the study of pollen grains plays a vital role in many research fields. One of them is forensic palynology, which uses pollen as a proxy to link individuals or objects to a location or instance. It relies on the fact that (1) pollen is an ever-present feature of the environment; (2) different locations have different pollen signatures, allowing for inference related to spatial tracking; (3) plants bloom at different times, allowing for temporal inference; and (4) pollen is exceptionally durable and can be used for forensic studies decades after sample collection. In addition, forensic palynology has played a role in many criminal investigations, mainly investigations dealing with homicide, violent assault, rape, genocide, terrorism, and suspected terrorism. Identifying plant species from their pollen relies on two traditional methods: microscopy or genetic analysis. On the one hand, microscopy relies on identifying pollen grains using their morphology (i.e., size, shape, and wall structure) and comparing it to an image library for accurate identification. On the other hand, genetic analysis characterizes pollen species using a short DNA sequence from a universal standard in the genome. Both methods have so far been mutually exclusive. The standard procedure for microscopy is to clean the grain through acetolysis, which destroys any genetic material in the sample. Studies involving genomic characterization of the plant material require the release of the genomic material by mechanically crushing the grain, which can no longer be analyzed for morphology through microscopic methods. While the number of forensic palynological studies increases, they usually rely on only one of the two techniques above and rarely show the potential for an efficient analysis of individual grains within an assemblage to statistically evaluate the species distribution in the mixture of grains that can be the evidence. During this Ph.D. research, a new method for pollen DNA extraction was developed that does not destroy the pollen grain, getting around both crushing and acetolysis approaches. After evaluating the non-destructive nature of the new protocol by microscopy, single pollen grains from a variety of common species were examined using universally accepted genetic markers (rbcL, matK, and ITS2) for DNA analysis. The sequencing of the different species was also performed and discussed to evaluate the potential for single species identification from databases. Finally, the developed approach for non-destructive DNA extraction was evaluated on a complex object, a car cabin air filter, showing how microscopic plant evidence (pollen and debris) analysis can easily provide information in an investigation.