La especie albaricoquero (P. armeniaca L.), originaria de China y Asia Central, se cultiva en España principalmente en Murcia y Valencia. La aparición y extensión del virus de la Sharka ha puesto de manifiesto la necesidad de obtener nuevas variedades resmoleculares que se han definido útiles en los procesos de selección en programas de mejora: RFLPs (Restriction Fragment Lenght Polimorphism), RAPDs (Random Amplified Polimorphic DNA) y AFLPs (Amplified Fragment Length Polimorphism).Con ellos se ha realizado un estudio de diversidad genética, utilizando 16 variedades de albaricoquero procedentes de Francia, España y Norteamérica, que incluyen variedades resistentes y susceptibles a Sharka. Algunas de ellas se están utilizando como genitores en el programa de mejora del IVIA. Se ha elaborado el primer mapa genómico de la especie albaricoquero, basado en los marcadores moleculares RAPDs y AFLPs. Se ha estudiado la herencia del carácter resistencia a Sharka, y se ha establecido la hipótesis de herencia basada en 2 genes independientes.Con el fin de obtener marcadores moleculares ligados a los caracteres autoincompatibilidad y androesterilidad en albaricoquero, se ha utilizado la técnica del Bulk Segregation Analysis (BSA) combinada con marcadores tipo RAPD. / Hurtado Ruiz, MA. (1999). Obtención de marcadores moleculares para su aplicación a la mejora genética del albaricoquero [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/5426

Using four AFLP markers and seven polymorphic microsatellite loci, we examined the genetic structure of the rare and endangered Spiranthes parksii Correll (Orchidaceae). Spiranthes parksii is not distinguishable from sympatric S. cernua (L.) Rich based on these data, though low levels of polymorphisms exist within both. These low levels of genetic diversity are likely a result of high levels of agamospermic reproduction through adventitious embryony. These results suggest that both S. parksii, as well as the sympatric, open flower form of S. cernua, are products of the more widely distributed S. cernua complex. Further, another local form of S. cernua, distinguished by its tendency to produce closed flowers is genetically distinct from both S. parksii, as well as the openflower form of S. cernua, as shown by AFLPs and microsatellite loci. This is the first known set of microsatellite primers developed specifically for use in Spiranthes. The application of these markers may be used to address other unresolved relationships among species of Spiranthes, many of which are also endangered or have populations in decline.

No description available.

Made available in DSpace on 2017-07-25T19:30:51Z (GMT). No. of bitstreams: 1 Cristiane Romanek.pdf: 2518407 bytes, checksum: a9fd5d1b1e96d98a44dfc90dfaa0a4b6 (MD5) Previous issue date: 2014-12-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objectives of this study were to characterize the resistance/susceptibility of the F2:3 maize progenies to anthracnose leaf blight (Colletotrichum graminicola), to estimate the genetic parameters associated with resistance, and map the genomic regions associated with quantitative resistance loci (QRL) by means molecular markers microsatellites (SSRs) and AFLPs. The inbred lines L04-2 (resistant) and L95-1 (susceptible) were crossed to generate an F2 population. Individuals of this population were selfed resulting F2:3 progenies, these were evaluated in three trials conducted in a randomized block design, with three replications. The treatments were consisted of 121 F2:3 progenies, parental lines and F1 generation. Plants were inoculated in two times between the stages V6 and V7, the second inoculation made seven days after the first. Three evaluation of the severity of anthracnose leaf blight were conducted: the 1st in VT (flowering) stage, 2nd in R2 and 3rd in R3 through a note scale with amplitude from 1 to 6. From the point assessments, was calculated the area under the disease progress curve (AUDPC). The results showed highly significant effects for both point assessments for AUDPC, indicating high genetic variability for resistance to anthracnose leaf blight among the F2:3 progenies. The high magnitude of genetic parameters indicate that the genetic control of resistance to anthracnose leaf blight of corn is associated with the expression of genes of great phenotypic effect. QRL mapping was conducted based on phenotypic analysis of 121 F2:3 progenies, evaluated in three experiments for three point assessments and AUDPC. Linkage analysis between the markers (microsatellites and AFPLs) and QRLs was performed by analysis of multiple linear regression and by composite interval mapping. Multiple linear regression identified mark SSRs and AFPLs highly associated with resistance alleles, the E55139 and E56386 AFLPs loci with the highest partial regression coefficients for the three experiments, with amplitudes from 6,67 to 31,31 % and 6,12 to 21,78 %, respectively. Were mapped 19 QRLs to anthracnose leaf blight in eight linkage groups. Six QRLs were the most stable environments for different evaluation and responsible for the large magnitude of the phenotypic variation in resistance. The high number of QRLs mapped in this population confirms the pattern of quantitative inheritance of resistance in tropical maize to anthracnose leaf blight caused by C. graminicola. / Os objetivos deste trabalho foram caracterizar a resistência/suscetibilidade de progênies F2:3 de milho à antracnose foliar (Colletotrichum graminicola), estimar os parâmetros genéticos associados à resistência, e mapear as regiões genômicas associadas à resistência quantitativa (QRL) por meio de marcadores moleculares microssatélites (SSRs) e AFLPs. As linhagens endogâmicas L04-2 (resistente) e L95-1 (suscetível) foram cruzadas entre si a fim de gerar uma população F2. Os indivíduos desta população foram autofecundados dando origem as progênies F2:3 que foram avaliadas em três experimentos, conduzidos no delineamento de blocos casualizados com três repetições. Os tratamentos foram constituídos de 121 progênies F2:3, linhagens parentais e geração F1. As plantas foram inoculadas por duas vezes entre os estádios V6 e V7, sendo a 2ª inoculação realizada sete dias após a 1ª. Foram realizadas três avaliações da severidade da antracnose foliar: a 1ª no estádio VT (pendoamento), a 2ª em R2 e a 3ª em R3 através de uma escala de notas com amplitude de 1 a 6. A partir das avaliações pontuais, calculou-se a área abaixo da curva de progresso da doença (AACPD). Os resultados evidenciaram efeitos altamente significativos tanto para as avaliações pontuais quanto para a AACPD, indicando grande variabilidade genética para a resistência à antracnose foliar entre as progênies F2:3. As elevadas magnitudes dos parâmetros genéticos indicam que o controle genético da resistência de milho à antracnose foliar esteja associado à expressão de genes de grande efeito fenotípico. O mapeamento de QRLs foi realizado com base na análise fenotípica das 121 progênies F2:3, avaliadas em três experimentos para as três avaliações pontuais e para a AACPD. A análise de ligação entre os marcadores (microssatélites e AFPLs) e os QRLs foi efetuada por meio da análise de regressão linear múltipla e pelo mapeamento por intervalo composto. A regressão linear múltipla identificou marcas SSRs e AFPLs altamente associadas a alelos de resistência, sendo os locos AFLPs E55139 e E56386 com os maiores coeficientes de regressão parciais para os três experimentos, com amplitude de 6,67 a 31,31 % e de 6,12 a 21,78 %, respectivamente. Foram mapeados 19 QRLs à antracnose foliar em 8 grupos de ligação. Seis QRLs foram mais estáveis para os diferentes ambientes de avaliação e responsáveis por grande magnitude da variação fenotípica em resistência. O elevado número de QRLs mapeados nesta população confirma o padrão de herança quantitativa da resistência de milho tropical à antracnose foliar causada por C. graminicola.

Discerning the basis of phenotypic and genotypic differences within and between taxa is crucial for understanding the evolution of species, subspecies or varieties and races. In this dissertation, I have presented three studies, which use morphological characters and genetic Amplified Fragment Length Polymorphisms (AFLPs) to differentiate cytotypes, populations and species of the genus Xanthisma. The first study is aimed at clarifying the species status of Haplopappus ravenii, which has been considered to be a separate species by some taxonomists and a race of Xanthisma gracile by other researchers. Considering the morphological species concept and the genotypic cluster definition of a species, there was insufficient distinction in either dataset to support these taxa as distinct species. It was found that H. ravenii is more appropriately classified as a a cytotype or a race of X. gracile. In the second study, the genetic structure of X. gracile was quantified across populations occupying distinct habitat types (desert, grasslands, and pinyon juniper woodlands) in order to test the hypothesis of local adaptation and to determine the potential for intraspecific divergence. Samples from desert habitats showed higher genetic divergence than samples in the other two habitats. This study is indicative of local adaptation of populations and that changes in climate and habitat play a very important role in the genetic differentiation of plant systems. The third study evaluated the taxonomy of Xanthisma spinulosum and three of its subspecies that co-occur in Arizona. Herbarium specimens representative of the three subspecies were used to test for significant morphological and genetic divergence that would support their recognition. The morphological characters originally utilized by taxonomists who named these taxa were not significantly different among the three taxa. This finding was further supported by the molecular data, suggesting the presence of one contiguous species. This dissertation aims at stressing the importance of taxonomic status and understanding the role that environment can play on shaping differentiation between taxa.

The ecology, species distribution, and population structure of Armillaria was investigated in the forests of Massachusetts. From 64 plots at 16 sites, 640 isolates of Armillaria were collected from six forest types (northern hardwoods, mixed oak, pitch pine, white pine, white pine/mixed oak, and eastern hemlock). Armillaria gallica proved to be the most abundant species, making up 316/640 (52%) of all isolations. This was followed by A. solidipes (219/640; 34%), A. mellea (46/640; 7%), A. calvescens (36/640; 6%), A. gemina (16/640; 3%), and A. sinapina (7/640; 1%). Armillaria gallica was routinely encountered causing significant decay of the lower bole on living hardwood hosts, especially oaks. The population structure of 153 isolates of A. gallica collected from mixed oak forests was investigated using amplified fragment length polymorphisms (AFLPs). From a total sampling area of 4.51 ha, 38 AFLP genotypes were discovered, yielding a figure of eight genets per hectare with the average A. gallica genet occupying 0.13 ha. When the effects of hydrolyzable tannins on in vitro growth were compared between A. calvescens and A. gallica, it was A. gallica that appeared better at oxidizing and metabolizing commercial tannins (tannic acid and gallic acid) along with black oak root bark extracts. This was determined through measurements of colony area and dry biomass, and suggests that A. gallica may be a better adapted pathogen of oak. In order to more accurately distinguish between isolates of A. calvescens and A. gallica, a three-gene phylogeny was reconstructed, using partial sequences of the elongation factor 1-alpha (tef1), RNA polymerase II (rpb2) and nuclear large subunit (nLSU) genes. After comparing 12 isolates each of A. calvescens and A. gallica that originated from across northeastern North America, only the tef1 gene could accurately distinguish these two species. Five single nucleotide polymorphisms were present between the two species and maximum likelihood and maximum parsimony methods grouped A. calvescens and A. gallica into monophyletic clades.

We are now in the midst of a mass extinction crisis. The top threats to biodiversity include habitat destruction, pollution, over-harvesting, and invasive species. The field of conservation genetics seeks to understand these threats and devise management to preserve taxa with the ability to cope with environmental change. Preserving genetic variation and the processes in which variation is created and maintained is vital to long-term conservation goals. Limited conservation resources are cause for the prioritization of taxa and areas. Nine basic methods of prioritization have been developed. Though there are differences in these methods, and thus in the resulting target areas, many, including biodiversity hotspots, list Mesoamerica, in which the highest diversity of iguanids confined to a single genus, Ctenosaura, occur. Though ctenosaurs are the most diverse genus of iguanas, have the most Redlisted species, lack protection and are in danger of extinction, they have been overlooked. The Ctenosaura palearis complex, occurs in central Mesoamerica and is made up of four endangered species. In order aid in the conservation of this biodiversity, a multi-scale molecular evaluation of this complex was preformed. I first used a species tree approach to elucidate the relationships between the focal species, showing that these species have gone through recent and rapid speciation, resulting in four closely related endemics. Thus, the nominal groupings should be upheld and given individual protection. Second, I evaluated the degree to which gene flow from the widely distributed congener threatens the genetic distinctiveness of the endemic C. bakeri. Low levels of introgression indicated no current threat. Hybridization could increase if habitat destruction or changes in relative abundance increase the probability of interbreeding. Continued monitoring of this situation is justified. Third, I used a variety of population genetic techniques to elucidate the genetic structure within and among populations of C. melanosterna. These results indicate that the populations in the Valle de Aguán and Cayos Cochinos are not interchangeable thus protection of both areas is necessary, and extreme caution should be used when implementing breeding and translocation programs. Local conservation efforts may be evaluated and developed using this information.

No description available.

Nothofagus moorei is a long-lived, Gondwana relict cool temperate rainforest tree. Nothofagus-dominated rainforests were widespread across much of eastern Australia during the mid-Tertiary but today, N. moorei occurs only as a series of disjunct, isolated populations in south-east Queensland and northern New South Wales. Clonal regeneration via coppicing is reported to be a common feature of most N. moorei populations, while successful sexual regeneration is believed to be rare, occurring largely only in niches with high light levels and limited competition. While clonal propagation enables population persistence and individual longevity, it cannot generate novel genotypes. Isolated populations, potentially high levels of clonality, low-potential for successful sexual regeneration, long-lived individuals and predicted global warming effects make N. moorei vulnerable to local, if not total, population extinction. The current study aimed to assess the relative conservation status of extant N. moorei populations in order to develop appropriate conservation management strategies for long-term population persistence. Levels of genetic diversity and population structure were examined across the remaining natural distribution of N. moorei using nuclear amplified fragment length polymorphism (AFLP), microsatellite and chloroplast DNA markers. In total 607 individuals were sampled from 20 populations and 5 geographical regions: Lamington/Border Ranges, Ballow, Dorrigo/New England, Werrikimbe and Barrington. Genetic results were then analysed to assess conservation status of each population and geographical region. Microsatellite and AFLP data identified comparatively high levels of genetic diversity in all remnant populations sampled. The prevalence of coppicing in the northern Lamington/Border Ranges populations appears to have had little impact on relative levels of genetic diversity, heterozygosity or population structure. Population differentiation was limited, with the majority of genetic variation retained within populations, no regional structuring and high levels of admixture. Analysis of cpDNA variation showed that the three Dorrigo/New England populations were divergent from all other populations, suggesting an ancient divergence in N. moorei prior to Pleistocene glaciations. While levels of genetic diversity were essentially the same across all populations, Bayesian analysis of genetic structure did identify four populations with differing gene pool proportions which would be important to include in conservation efforts in addition to individuals from other populations. Similarly, individuals from four significantly differentiated groups identified using traditional F-statistics suggests individuals from each of these four groups should be included in future conservation plans. In order to maintain ancient chloroplast lineages, populations from the Dorrigo/New England region should also be assigned special conservation value. Populations of N. moorei appear to have retained significant levels of genetic diversity and show little population divergence in spite of marked reductions in the natural distribution since the Early Miocene. Sampling of these ancient trees however, suggests current levels of diversity in N. moorei actually reflect past diversity and differentiation, and that there have been insufficient generations since the historical contraction in distribution for genetic diversity to be adversely affected and regional differentiation to evolve. Long-term persistence of N. moorei is still threatened by future accelerated climate change and the limited preferred habitat that remains where N. moorei can expand its range. While the ability to regenerate clonally may enable long-term persistence of N. moorei, populations are still likely to continue to decline as climatic conditions will increasingly favour sub-tropical and warm temperate species across much of N. moorei's northern distribution. Southern populations of N. moorei, in contrast, could expand their ranges into eucalypt woodlands as predicted climate becomes warmer and wetter. However, this will ultimately be determined by the frequency of fires, with increased fire frequencies favouring the expansion of eucalypts and contraction and possible local population extinction of N. moorei dominated cool temperate rainforests.