For the South African forestry industry, the patula pine (Pinus patula) is the most commercially important softwood species. A pine clonal programme has yet to be fully implemented in this country and at present much effort is being made to establish clonal plantings of selected trees. In order to accomplish this, it is essential that satisfactory commercially viable propagation technologies be developed for this species. This study examined the possibilities and constraints of three different in vitro systems for mass propagation of rare and important P. patula material. Seed germination and sterilisation techniques were developed for adventitious bud and somatic embryogenesis experimentation. Adventitious buds were initiated from excised 'mature P. patula embryos cultured on LM medium containing 5 mg 1-1 BA. Although, between 50 and 60% of the embryo explants produced adventitious buds, only 3-5 buds per explant actually developed further to form distinct shoots. The adventitious shoots elongated slowly (±8 mm in 2 months) on LM medium, containing 10 g 1-1 activated charcoal. Axillary buds were induced on 10 week-old juvenile shoots, after the development of an effective surface sterilisation procedure, using 0.02% HgCL2. The effect of removing the apex and trimming the needles on bud induction was significant. Dwarf shoots elongated at a rate of 25 mm in 5 weeks. Rooting studies conducted on juvenile P. patula shoots indicated that the most effective treatment was wounding the shoot base and placing the shoot in composted bark growing medium, under a greenhouse mist regime. Rooting percentages were low (50%). Included in this study is the first successful production of somatic pro-embryos from mature Pinus patula embryos. Calli were produced on LM induction medium containing 2 mg 1-1 2,4-D. Cultures were first placed in the dark for 4 weeks and then transferred to a 16 h photoperiod for a further 2 weeks, after which Stage 1 embryogenic cells were observed. When calli were placed on LM maturation medium, containing 12 mg 1-1 ABA, for a further 6-8 weeks, pro-embryo structures (maximum of 7 pro-embryos per callus) were detected embedded In the callus mass. Hence, investigations into the development of protocols for the micropropagation of Pinus patula, were undertaken. Two major constraints for applying in vitro techniques to the commercial production of pine were identified: the poor yield of shoots and pro-embryos and the length of time taken for plantlets to be produced. This study, however, provides some fundamental knowledge and background work required by tree breeders who wish to implement biotechnological techniques in the selection and improvement of P. patula genotypes. / Thesis (M.Sc.)-University of Natal, Durban, 1993.

v, 181 leaves : ill., tables ; 29 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy, 1980

Genetic consistency within varieties is essential to quality assurance for any agricultural product. While the Australian coffee industry targets high quality coffee, there is observed morphological variation within coffee varieties in New South Wales plantations. This variability may result from environmental, genetic and/or management factors. Genetic factors can be tested by molecular markers which can also shed light on the questions concerning crop quality management. A review of the literature showed low genetic variation in C. arabica. Hence four different molecular marker systems were used in this study to detect possible genetic variation within and between varieties of local coffee grown in Northern New South Wales (NNSW), Australia. Genetic variation in eighty-four seed propagated coffee (C. arabica) accessions, mainly from two commercial varieties (K7 and CRB) in NNSW, were tested using various PCR-based marker systems (RAPDs, ISSRs, SSRs and AFLPs). Eleven accessions from Central Highland, Vietnam, were used as reference material. While RAPD and ISSR did not distinguish intra-varietal molecular variation, SSR and AFLP data revealed the degree of genetic variability and the relationship among individuals within and between coffee varieties. Despite observed morphological variation within supposedly single variety plantations in NNSW, the genetic variation, measured by genetic distance, revealed in this study was very low (K7: 0.193; CRB: 0.205). There exists genetic variation between different farms sharing the same cultivar (K7) which suggests differences in the management of plantation establishment and sourcing of trees. The genetic variability is not aligned with off-type individuals observed in K7, but is with off-type CRB plants which is probably due to inter-varietal hybrids from unintentional outcrossing. The mean level of genetic identity between cultivars derived from the two distinct types of C. arabica is moderate (0.641). Although genetic variation within and among arabica cultivars is low, sufficient DNA polymorphism was found among some C. arabica accessions to allow differentiation. The results in this study suggested that even the elite cultivars, which have been exposed to intensive selection, still show a certain degree of genetic variation amongst individuals within each cultivar even though C. arabica is a predominantly selfing species and has a narrow genetic foundation. The congruence between AFLP and SSR data sets suggests that either method individually, or a combination, is applicable to genetic studies of coffee. SSR alone clearly distinguished and revealed inter-varietal heterogeneity but were more powerful when combined with AFLP.

Thesis (Ph. D.)--University of Kentucky, 2008. / Title from document title page (viewed on May 13, 2008). Document formatted into pages; contains: vi, 82 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 76-81).

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Made available in DSpace on 2014-06-11T19:32:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-07-01Bitstream added on 2014-06-13T19:02:38Z : No. of bitstreams: 1 000742478.pdf: 1974664 bytes, checksum: dc2262a383cbe844716ced4a1eea54c6 (MD5) / A disponibilidade de promotores órgão/tecido-específicos responsáveis pela regulação de genes responsivos a estresses bióticos e abióticos constitui uma ferramenta fundamental para os programas de melhoramento genético do café (Coffea arabica) visando o incremento de resistência e tolerância. Relatamos aqui a caracterização de um promotor do gene que codifica uma provável peroxidase III em C. arabica (CaPrx), peroxidases da classe III (Prxs) são enzimas envolvidas numa variedade de processos fisiológicos relacionados com o estresse em plantas. A CaPrx é expressa em estágios iniciais da interação com o nematóide de galha (RKN). CaPrx mostrou expressão aumentada nas raízes de café inoculadas com RKN (Meloidogyne paranaensis) (12 h após a inoculação), mas nenhuma diferença significativa foi observada na expressão entre as plantas suscetíveis e resistentes. Ensaios com plantas de tabaco transgênicas portadoras do promotor CaPrx fusionado com o gene que codifica a β-glucuronidase (GUS), revelou que este promotor foi exclusivamente ativo nas galhas induzidas por RKN (Meloidogyne javanica). Em seções transversais de galhas, o repórter GUS foi detectado predominantemente em células gigantes. Um aumento na expressão do gene GUS em raízes de tabaco transgênicos foi detectado 16 horas pós-inoculação por RKN. Por outro lado, nenhuma alteração na expressão de GUS após tratamento com ácido jasmônico foi detectada. Um segundo estudo foi realizado a fim de desvendar o papel de um fator WRKY de café (CaWRKY1) na regulação do promotor do gene que codifica uma isoflavona redutase em café (CaIRL). Fatores de transcrição do tipo WRKY estão envolvidos na regulação da expressão de diversos genes de defesa em plantas. A região promotora do gene CaIRL possui diversos sítios W-boxes ao longo de sua sequência. Através de análises de deleção e ensaios de transativação... / Not available

Made available in DSpace on 2014-06-11T19:32:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-04Bitstream added on 2014-06-13T20:03:21Z : No. of bitstreams: 1 pazeto_msr_dr_jabo.pdf: 783609 bytes, checksum: 91ee1030f9bdf68e2c826ba05a29ca65 (MD5) / O gênero Jatropha pertencente à família Euphorbiaceae possui cerca de 170 espécies distribuídas nas regiões semi-áridas tropicais da África e das Américas. Dentre as espécies do gênero Jatropha, encontram-se o pinhão-manso (J. curcas L.), o pinhão-bravo (J. pohliana Müell), como é conhecido no Brasil e o pinhão-roxo (J. gossypiifolia L.). Estudos da variabilidade fenotípica e genética de uma população são importantes para melhoristas de plantas, pois auxiliam na caracterização de acessos, além de facilitar na seleção de parentais para cruzamentos direcionados. Assim, o presente estudo objetivou avaliar acessos de três espécies do gênero Jatropha de diferentes regiões do Brasil, por meio de caracteres morfológicos e marcadores moleculares ISSR, visando agrupá-los de acordo com o grau de divergência existente. Observou-se maior variabilidade interespecífica do que intraespecífica para grupos de acessos, tanto para caracteres morfológicos quanto para moleculares. Caracteres qualitativos e quantitativos mostraram variabilidade entre acessos e poderão servir como base em estudos genéticos futuros de espécies Jatropha. Não houve relação entre o padrão de similaridade e a procedência geográfica de acessos nas análises de agrupamentos pelo método UPGMA. A porcentagem média de polimorfismo encontrada para marcadores ISSR entre os acessos estudados foi de 40,6%. Houve maior similaridade genética entre acessos de J. pohliana e J. gossypiifolia e menor entre J. pohliana e J. curcas. / The genus Jatropha belongs to the Euphorbiaceae family, it has about 170 species distributed in tropical semi- arid regions of Africa and the Americas. Among the species of Jatropha are physic nut (J. curcas L.), pinhão-bravo (J. pohliana Müell), as is known in Brazil and purple pinion (J. gossypiifolia L.). Studies of phenotypic and genetic variability of a population are important for plant breeders, as they help in the characterization of accessions, and facilitate the selection of parents for crosses targeted. Thus, the present study aimed to evaluate Jatropha accessions of three species by morphological characters and ISSR molecular markers in order to group them according to the degree of divergence. There was greater variability in interspecific than intraspecific groups to access, both for morphological and molecular characters. Qualitative and quantitative characters showed variability among accessions and could serve as a basis for future genetic studies of Jatropha species. There was no relation between the pattern of similarity and geographic origin of accessions in the cluster analysis by UPGMA. The average percentage of polymorphism for ISSR found among the accessions studied was 40.6%. There was greater genetic similarity among accessions of J. pohliana and J. gossypiifolia and lower among J. pohliana and J. curcas.

Made available in DSpace on 2014-06-11T19:32:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-08Bitstream added on 2014-06-13T20:03:24Z : No. of bitstreams: 1 viegas_mp_dr_jabo.pdf: 946056 bytes, checksum: 35a4f6bce097b276024db20a4297c585 (MD5) / Os marcadores microssatélites têm sido utilizados com frequência como ferramenta efetiva para estudos de diversidade e sistema reprodutivo de populações, possuem aplicabilidade prática, uma vez que podem ser obtidos pela construção de bibliotecas genômicas enriquecidas. Este trabalho teve como objetivo desenvolver e validar iniciadores SSR polimórficos para a espécie Pterogyne nitens e analisar a diversidade genética e o sistema reprodutivo de duas gerações dessa espécie em duas populações distintas. Foram avaliadas uma população localizada na cidade de Jaboticabal-SP (Pop. JB) e outra na cidade de Pereira Barreto-SP (Pop. PB), sendo 10 árvores matrizes e 30 progênies de cada árvore de cada população. Observou-se um total de 48 alelos para as duas gerações da Pop. JB e 41 alelos para a Pop. PB... / Microsatellites molecular markers have been used with frequency as an effective tool for studies of diversity and reproductive system of the populations, have practical applicability, since they can be obtained by the construction of enriched genomic libraries. The aim of this work was to develop and validate SSR polymorphic iniciadores for the Pterogyne nitens species, and to analyze the genetic diversity and the reproduction system of two generations of this species in two different populations. The two populations evaluated are located in Jaboticabal-SP (Pop. JB) and Pereira Barreto-SP (Pop. PB) municipalities. It was evaluated 10 tree matrices and 30 progenies from each tree of each population. The results showed a total of 48 alleles... (Complete abstract click electronic access below)

Made available in DSpace on 2015-05-14T16:53:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-20Bitstream added on 2015-05-14T16:58:45Z : No. of bitstreams: 1 000829290.pdf: 277582 bytes, checksum: 7643ef4631e134350d930bfede4934b7 (MD5) / Como conseqüência do melhoramento de populações, novas ideias e métodos surgiram, procurando melhorar a eficiência na obtenção de linhagens e híbridos, bem como diminuir o tempo requerido na sua obtenção. Este é o caso do método dos Híbridos Crípticos, que corresponde essencialmente a um teste precoce de combinação através de cruzamentos entre plantas individuais. Apesar da possibilidade do método dos Híbridos Crípticos representar um ganho de tempo na produção de híbridos, pode ser considerado de uso restrito em programas de melhoramento de espécies alógamas, principalmente em decorrência da excessiva perda de vigor das linhagens femininas com a condução de sucessivas autofecundações. No tocante, supõe-se que em programas de melhoramento de espécies que possuem o sistema reprodutivo do tipo misto, o método possa se configurar como uma ferramenta efetiva em razão de que nestas espécies a depressão endogâmica é desprezível. Ao encontro da necessidade de informações que permitam avaliar o real potencial do método dos Híbridos Crípticos em espécies com sistema reprodutivo do tipo misto, objetivou-se neste trabalho analisar comparativamente o comportamento dos híbridos de mamoneira (Ricinus communis L.) produzidos pelo processo convencional, em que as linhagens são extraídas pelo método “Standard”, com os obtidos pelo método dos Híbridos Crípticos. O estudo relata resultados de quatro caracteres agronômicos - produtividade de grãos, teor de óleo, produtividade de óleo e altura de plantas - de 24 híbridos / As a consequence of population breeding, new ideas and methods have arisen in order to improve the efficiency in obtaining lines and hybrids, as well as to decrease the time required for their production. This is the case of the Cryptic Hybrids method, which corresponds essentially to an early combination test through breeding between individual plants. Although the Cryptic Hybrids method may represent time gain in hybrid production, it can be considered of restrict use in breeding programs of allogamous species, mainly due to excessive vigor loss in female lines with the conduction of successive self-pollinations. In breeding programs of species with mixed reproductive system, the method is supposed to be an effective tool since endogamic depression is negligible in these species. Based on the need of information that allow assessing the real potential of the Cryptic Hybrids method in mixed reproductive system, this study aimed to comparatively analyze the behavior of castor bean (Ricinus communis L.) hybrids produced through the conventional process, in which the lines are extracted by the Standard method, relative to those obtained by the Cryptic Hybrids method. The study reports grain productivity, oil content, oil productivity and plant height results for 24 interpopulational hybrids, of which 12 were conventionally produced and the other 12 were produced by the Cryptic Hybrids method; all of them were synthesized at the Department of Plant Production of the School of Agronomical Sciences.