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• 81. [Article] The growth of wild-type and genetically-marked strains of Tilletia caries and T. controversa in susceptible and resistant wheat cultivars

  The objective of this study was to provide basic information on the interaction of the bunt fungi Tilletia caries and T. controversa with their host, Triticum aestivum. Studies on the ability of haploid strains ...

  Citation × Citation Citation Abstract Copy Title: The growth of wild-type and genetically-marked strains of Tilletia caries and T. controversa in susceptible and resistant wheat cultivars Author: Trail, Frances The objective of this study was to provide basic information on the interaction of the bunt fungi Tilletia caries and T. controversa with their host, Triticum aestivum. Studies on the ability of haploid strains to colonize wheat heads provided the basis for experiments in which haploid strains were crossed in planta. Wild-type and genetically-marked haploid strains of T. caries and T. controversa injected into boot-stage heads of susceptible and resistant wheat cultivars were recovered from the mature heads 4 to 6 weeks after introduction. Viable teliospores were produced following successful matings of sexually compatible haploid cultures of T.caries and T.controversa injected into boot-stage heads which were grown both in intact plants and in an organ culture system for wheat heads. The organ culture system adopted here was determined to simulate natural infection under controlled environmental conditions. It served as a basis for the production of hybrid teliospores formed between strains of T. caries and T. controversa. The kinetics of teliospore germination of T. caries, T. controversa and hybrids formed by the cross of T. caries, and a genetically-marked strain of T. controversa, were determined. The time required for germination of the hybrid teliospores at 4C was intermediate to that of the parents, suggesting that this trait may be controlled by a single gene which exhibits incomplete dominance. Teliospores of the Fl generation failed to germinate at 18C suggesting that this trait is controlled by a dominant gene present in the T. controversa parental strain. The genetic marker was recovered in the Fl generation, indicating that drug-resistance markers may be used in future crosses. Title: The growth of wild-type and genetically-marked strains of Tilletia caries and T. controversa in susceptible and resistant wheat cultivars Author: Trail, Frances The objective of this study was to provide basic information on the interaction of the bunt fungi Tilletia caries and T. controversa with their host, Triticum aestivum. Studies on the ability of haploid strains to colonize wheat heads provided the basis for experiments in which haploid strains were crossed in planta. Wild-type and genetically-marked haploid strains of T. caries and T. controversa injected into boot-stage heads of susceptible and resistant wheat cultivars were recovered from the mature heads 4 to 6 weeks after introduction. Viable teliospores were produced following successful matings of sexually compatible haploid cultures of T.caries and T.controversa injected into boot-stage heads which were grown both in intact plants and in an organ culture system for wheat heads. The organ culture system adopted here was determined to simulate natural infection under controlled environmental conditions. It served as a basis for the production of hybrid teliospores formed between strains of T. caries and T. controversa. The kinetics of teliospore germination of T. caries, T. controversa and hybrids formed by the cross of T. caries, and a genetically-marked strain of T. controversa, were determined. The time required for germination of the hybrid teliospores at 4C was intermediate to that of the parents, suggesting that this trait may be controlled by a single gene which exhibits incomplete dominance. Teliospores of the Fl generation failed to germinate at 18C suggesting that this trait is controlled by a dominant gene present in the T. controversa parental strain. The genetic marker was recovered in the Fl generation, indicating that drug-resistance markers may be used in future crosses. Close

• 82. [Article] High-Throughput Sequencing of Arabidopsis microRNAs : Evidence for Frequent Birth and Death of MIRNA Genes

  In plants, microRNAs (miRNAs) comprise one of two classes of small RNAs that function primarily as negative regulators at the posttranscriptional level. Several MIRNA genes in the plant kingdom are ancient, ...

  Citation × Citation Citation Abstract Copy Title: High-Throughput Sequencing of Arabidopsis microRNAs : Evidence for Frequent Birth and Death of MIRNA Genes Author: Kasschau, Kristin D., Dangl, Jeffrey L., Grant, Sarah R., Howell, Miya D., Carrington, James C., Law, Theresa F., Sullivan, Christopher M., Fahlgren, Noah, Cumbie, Jason S., Givan, Scott A. In plants, microRNAs (miRNAs) comprise one of two classes of small RNAs that function primarily as negative regulators at the posttranscriptional level. Several MIRNA genes in the plant kingdom are ancient, with conservation extending between angiosperms and the mosses, whereas many others are more recently evolved. Here, we use deep sequencing and computational methods to identify, profile and analyze non-conserved MIRNA genes in Arabidopsis thaliana. 48 nonconserved MIRNA families, nearly all of which were represented by single genes, were identified. Sequence similarity analyses of miRNA precursor foldback arms revealed evidence for recent evolutionary origin of 16 MIRNA loci through inverted duplication events from protein-coding gene sequences. Interestingly, these recently evolved MIRNA genes have taken distinct paths. Whereas some non-conserved miRNAs interact with and regulate target transcripts from gene families that donated parental sequences, others have drifted to the point of non-interaction with parental gene family transcripts. Some young MIRNA loci clearly originated from one gene family but form miRNAs that target transcripts in another family. We suggest that MIRNA genes are undergoing relatively frequent birth and death, with only a subset being stabilized by integration into regulatory networks Title: High-Throughput Sequencing of Arabidopsis microRNAs : Evidence for Frequent Birth and Death of MIRNA Genes Author: Kasschau, Kristin D., Dangl, Jeffrey L., Grant, Sarah R., Howell, Miya D., Carrington, James C., Law, Theresa F., Sullivan, Christopher M., Fahlgren, Noah, Cumbie, Jason S., Givan, Scott A. In plants, microRNAs (miRNAs) comprise one of two classes of small RNAs that function primarily as negative regulators at the posttranscriptional level. Several MIRNA genes in the plant kingdom are ancient, with conservation extending between angiosperms and the mosses, whereas many others are more recently evolved. Here, we use deep sequencing and computational methods to identify, profile and analyze non-conserved MIRNA genes in Arabidopsis thaliana. 48 nonconserved MIRNA families, nearly all of which were represented by single genes, were identified. Sequence similarity analyses of miRNA precursor foldback arms revealed evidence for recent evolutionary origin of 16 MIRNA loci through inverted duplication events from protein-coding gene sequences. Interestingly, these recently evolved MIRNA genes have taken distinct paths. Whereas some non-conserved miRNAs interact with and regulate target transcripts from gene families that donated parental sequences, others have drifted to the point of non-interaction with parental gene family transcripts. Some young MIRNA loci clearly originated from one gene family but form miRNAs that target transcripts in another family. We suggest that MIRNA genes are undergoing relatively frequent birth and death, with only a subset being stabilized by integration into regulatory networks Close

• 83. [Article] Pre-harvest sprouting tolerance of a synthetic hexaploid wheat (Triticum turgidum L. x Aegilops tauschii Coss.)

  Pre-harvest sprouting in wheat costs farmers millions of dollars every year. Pre-harvest sprouting tolerance (PST) has minimized this problem, but improvement of PST is still necessary. Synthetic hexaploid ...

  Citation × Citation Citation Abstract Copy Title: Pre-harvest sprouting tolerance of a synthetic hexaploid wheat (Triticum turgidum L. x Aegilops tauschii Coss.) Author: Rosa, Andre Cunha Pre-harvest sprouting in wheat costs farmers millions of dollars every year. Pre-harvest sprouting tolerance (PST) has minimized this problem, but improvement of PST is still necessary. Synthetic hexaploid wheats (synthetics) have been used as sources of genes coding for many useful traits. Two studies evaluated the PST of a synthetic (Altar 84/Aegilops tauschii) and investigated its potential as a source of PST in crosses with wheat cultivars. The first study compared the synthetic with selected wheat checks for PST and with its parent Altar 84 for the germination response of these genotypes to controlled wetting treatments applied to field-grown intact spikes and threshed seed. Spikes were rolled in wet germination paper and the percentages of germinated seed were determined after seven days. Threshed seeds in Petri dishes were wetted with water and vegetative floral tissues (chaff) extracts. Germinating seeds were counted daily for 14 days. The synthetic was more tolerant than Altar 84 and was classified as moderately sensitive. The improved PST of the synthetic over Altar 84 was attributed to Aegilops tauschii. Seed dormancy and water-soluble substances in the chaff of the synthetic and other genotypes appeared to contribute to their PST. The second study used random inbred F₅ lines obtained from single and backcrosses between the synthetic (red-seeded) and the sensitive wheat cultivars Opata F₅ (red-seeded) and Bacanora 88 (white-seeded). Seed coat color and germination responses of the F5 lines subjected to a five-day spike wetting treatment were evaluated. Pre-harvest sprouting tolerance was moderately to highly inheritable and largely controlled by additive gene effects in the studied populations. An association between red seed coat color and PST was observed but white recombinant lines more tolerant than their sensitive parent were obtained. The synthetic can be used to improve wheats with red and white seed coats. The potential use of the synthetic as a PST source was discussed and a breeding strategy suggested. Title: Pre-harvest sprouting tolerance of a synthetic hexaploid wheat (Triticum turgidum L. x Aegilops tauschii Coss.) Author: Rosa, Andre Cunha Pre-harvest sprouting in wheat costs farmers millions of dollars every year. Pre-harvest sprouting tolerance (PST) has minimized this problem, but improvement of PST is still necessary. Synthetic hexaploid wheats (synthetics) have been used as sources of genes coding for many useful traits. Two studies evaluated the PST of a synthetic (Altar 84/Aegilops tauschii) and investigated its potential as a source of PST in crosses with wheat cultivars. The first study compared the synthetic with selected wheat checks for PST and with its parent Altar 84 for the germination response of these genotypes to controlled wetting treatments applied to field-grown intact spikes and threshed seed. Spikes were rolled in wet germination paper and the percentages of germinated seed were determined after seven days. Threshed seeds in Petri dishes were wetted with water and vegetative floral tissues (chaff) extracts. Germinating seeds were counted daily for 14 days. The synthetic was more tolerant than Altar 84 and was classified as moderately sensitive. The improved PST of the synthetic over Altar 84 was attributed to Aegilops tauschii. Seed dormancy and water-soluble substances in the chaff of the synthetic and other genotypes appeared to contribute to their PST. The second study used random inbred F₅ lines obtained from single and backcrosses between the synthetic (red-seeded) and the sensitive wheat cultivars Opata F₅ (red-seeded) and Bacanora 88 (white-seeded). Seed coat color and germination responses of the F5 lines subjected to a five-day spike wetting treatment were evaluated. Pre-harvest sprouting tolerance was moderately to highly inheritable and largely controlled by additive gene effects in the studied populations. An association between red seed coat color and PST was observed but white recombinant lines more tolerant than their sensitive parent were obtained. The synthetic can be used to improve wheats with red and white seed coats. The potential use of the synthetic as a PST source was discussed and a breeding strategy suggested. Close

• 84. [Article] Patterns of genetic inheritance and variation through ontogeny for hatchery and wild stocks of Chinook salmon

  Although differences between selective pressures in hatcheries and streams have been theorized to cause genetic divergence between hatchery and wild salmonids, evidence of this is lacking. This study was ...

  Citation × Citation Citation Abstract Copy Title: Patterns of genetic inheritance and variation through ontogeny for hatchery and wild stocks of Chinook salmon Author: Hulett, Patrick L. Although differences between selective pressures in hatcheries and streams have been theorized to cause genetic divergence between hatchery and wild salmonids, evidence of this is lacking. This study was initiated to document the presence or absence of genetic change in hatchery and wild stocks by characterizing genetic traits in fish of various life history stages within a single generation. Nine biochemical traits (enzyme loci) and 12 meristic traits were characterized for adult fall chinook and one or more juvenile stages of their progeny of the 1984 brood year. Study groups consisted of hatchery-reared and naturally-reared subunits of populations in two tributaries of the lower Columbia River: Abernathy Creek and the Lewis River. Parents of both groups from Abernathy Creek were primarily of hatchery origin, whereas parents of both groups from the Lewis River were primarily of wild origin. The experimental design thus included reciprocal comparisons of hatchery and wild-reared groups from each of two stocks: one that has been propagated under hatchery conditions for at least five generations and one that has evolved in a stream environment. Both biochemical and meristic traits varied among adult and juvenile stages within hatchery and wild groups. Changes in some of these traits appear to have been caused by natural selection. This was true even for Abernathy hatchery and Lewis wild groups, which have been in the same environment for many generations. The direction and/or degree of change in some biochemical and meristic traits differed between hatchery and wild groups from a given stream, suggesting that selective pressures of the hatchery and wild environments differed in those cases. However, it could not be determined from these data whether the observed divergence of traits reflects general differences in hatchery and stream environments, or if it reflects population-specific responses to site-specific environmental conditions. The extent to which patterns of genetic change within a single generation might vary among year classes or generations is likewise unknown. Evidence of temporal changes in biochemical and meristic traits of hatchery and wild fish within a single generation has important implications regarding the use of those traits to characterize stocks. Assumptions of temporal stability of biochemical or meristic traits within or between year classes should be applied with caution. Sampling strategies of studies involving these characters should account for the possibility of temporal heterogeneity. Finally, these results suggest that workers using allozymes as genetic tags should test the assumption of selective neutrality of the particular allozyme markers being used. Title: Patterns of genetic inheritance and variation through ontogeny for hatchery and wild stocks of Chinook salmon Author: Hulett, Patrick L. Although differences between selective pressures in hatcheries and streams have been theorized to cause genetic divergence between hatchery and wild salmonids, evidence of this is lacking. This study was initiated to document the presence or absence of genetic change in hatchery and wild stocks by characterizing genetic traits in fish of various life history stages within a single generation. Nine biochemical traits (enzyme loci) and 12 meristic traits were characterized for adult fall chinook and one or more juvenile stages of their progeny of the 1984 brood year. Study groups consisted of hatchery-reared and naturally-reared subunits of populations in two tributaries of the lower Columbia River: Abernathy Creek and the Lewis River. Parents of both groups from Abernathy Creek were primarily of hatchery origin, whereas parents of both groups from the Lewis River were primarily of wild origin. The experimental design thus included reciprocal comparisons of hatchery and wild-reared groups from each of two stocks: one that has been propagated under hatchery conditions for at least five generations and one that has evolved in a stream environment. Both biochemical and meristic traits varied among adult and juvenile stages within hatchery and wild groups. Changes in some of these traits appear to have been caused by natural selection. This was true even for Abernathy hatchery and Lewis wild groups, which have been in the same environment for many generations. The direction and/or degree of change in some biochemical and meristic traits differed between hatchery and wild groups from a given stream, suggesting that selective pressures of the hatchery and wild environments differed in those cases. However, it could not be determined from these data whether the observed divergence of traits reflects general differences in hatchery and stream environments, or if it reflects population-specific responses to site-specific environmental conditions. The extent to which patterns of genetic change within a single generation might vary among year classes or generations is likewise unknown. Evidence of temporal changes in biochemical and meristic traits of hatchery and wild fish within a single generation has important implications regarding the use of those traits to characterize stocks. Assumptions of temporal stability of biochemical or meristic traits within or between year classes should be applied with caution. Sampling strategies of studies involving these characters should account for the possibility of temporal heterogeneity. Finally, these results suggest that workers using allozymes as genetic tags should test the assumption of selective neutrality of the particular allozyme markers being used. Close

• 85. [Article] An Examination of the Interrelationship Between Caregiver Behaviors, Infant Temperament and Perceptual-Cognitive Development

  The present study extended the Lewis and Goldberg (1968) study and included the parameter of infant temperament as defined by Thomas, Chess, Birch, Hertzig and Korn (1963). As in the Goldberg study, the ...

  Citation × Citation Citation Abstract Copy Title: An Examination of the Interrelationship Between Caregiver Behaviors, Infant Temperament and Perceptual-Cognitive Development Author: Stauffer, Anita E. Year: 1976 The present study extended the Lewis and Goldberg (1968) study and included the parameter of infant temperament as defined by Thomas, Chess, Birch, Hertzig and Korn (1963). As in the Goldberg study, the index of response decrement was used as a measure of the infant’s development. It was hypothesized that response decrement would be positively correlated with high frequency of caregiver stimulation and negatively correlated with high infant intensity and activity ratings. Response decrement is the measured decrease in the amount of time an infant looks at a novel stimulus after several trials. It was computed by observing the infant’s fixation to a single blinking light over four trials, and subtracting the total amount of time looking on trial from trial one. Title: An Examination of the Interrelationship Between Caregiver Behaviors, Infant Temperament and Perceptual-Cognitive Development Author: Stauffer, Anita E. Year: 1976 The present study extended the Lewis and Goldberg (1968) study and included the parameter of infant temperament as defined by Thomas, Chess, Birch, Hertzig and Korn (1963). As in the Goldberg study, the index of response decrement was used as a measure of the infant’s development. It was hypothesized that response decrement would be positively correlated with high frequency of caregiver stimulation and negatively correlated with high infant intensity and activity ratings. Response decrement is the measured decrease in the amount of time an infant looks at a novel stimulus after several trials. It was computed by observing the infant’s fixation to a single blinking light over four trials, and subtracting the total amount of time looking on trial from trial one. Close

• 86. [Article] Electron spin resonance of RCHCOR'radicals in X‑irradiated ketone‑urea inclusion compounds

  5 pages

  Citation × Citation Citation Abstract Copy Title: Electron spin resonance of RCHCOR'radicals in X‑irradiated ketone‑urea inclusion compounds Author: Griffith, O. H. Year: 2016, 1965 5 pages Title: Electron spin resonance of RCHCOR'radicals in X‑irradiated ketone‑urea inclusion compounds Author: Griffith, O. H. Year: 2016, 1965 5 pages Close

• 87. [Article] A mendelian study of Crassostrea gigas

  The genotype frequencies of one-year-old oyster spat (Crassostrea gigas) from parents of known genotype, are compared to the frequencies expected with Mendelian inheritance. The genotypes are characterized ...

  Citation × Citation Citation Abstract Copy Title: A mendelian study of Crassostrea gigas Author: Smoker, Janet Van Dusen The genotype frequencies of one-year-old oyster spat (Crassostrea gigas) from parents of known genotype, are compared to the frequencies expected with Mendelian inheritance. The genotypes are characterized at three enzyme loci, Aspartate amino-transferase (AAT), Phosphohexose isomerase (PHI) and Leucine aminopeptidase (LAP), and a general protein locus. In this study expression of these loci as histochemically stained patterns on a gel following electrophoresis is controlled by two codominant alleles at each locus. Frequencies of the genotypes at all four loci, in all offspring groups investigated, are not statistically different from those expected with Mendelian inheritance, supporting the hypothesis that this is the method of inheritance. It is further concluded that there are no large amounts of selection connected with any of these loci. An additional observation, that there is no statistical difference between genotype ratios of siblings in two different growing areas, is discussed in terms of G. Williams' (1975) "elm-oyster" model. It is suggested that the search for selection at single loci is probably not a generally useful one for the oyster breeder. Title: A mendelian study of Crassostrea gigas Author: Smoker, Janet Van Dusen The genotype frequencies of one-year-old oyster spat (Crassostrea gigas) from parents of known genotype, are compared to the frequencies expected with Mendelian inheritance. The genotypes are characterized at three enzyme loci, Aspartate amino-transferase (AAT), Phosphohexose isomerase (PHI) and Leucine aminopeptidase (LAP), and a general protein locus. In this study expression of these loci as histochemically stained patterns on a gel following electrophoresis is controlled by two codominant alleles at each locus. Frequencies of the genotypes at all four loci, in all offspring groups investigated, are not statistically different from those expected with Mendelian inheritance, supporting the hypothesis that this is the method of inheritance. It is further concluded that there are no large amounts of selection connected with any of these loci. An additional observation, that there is no statistical difference between genotype ratios of siblings in two different growing areas, is discussed in terms of G. Williams' (1975) "elm-oyster" model. It is suggested that the search for selection at single loci is probably not a generally useful one for the oyster breeder. Close

• 88. [Article] Simple sequence repeat marker development and use in European hazelnut(Corylus avellana L.)

  New highly polymorphic simple sequence repeat (SSR) markers for European hazelnut (Corylus avellana L.). were developed from several sources. The markers were characterized, and segregation in a mapping ...

  Citation × Citation Citation Abstract Copy Title: Simple sequence repeat marker development and use in European hazelnut(Corylus avellana L.) Author: Gurcan, Kahraman New highly polymorphic simple sequence repeat (SSR) markers for European hazelnut (Corylus avellana L.). were developed from several sources. The markers were characterized, and segregation in a mapping population allowed to assign them to linkage groups. Their transferability across genera and species in the Betulaceae family was investigated. SSR markers were used to fingerprint several hazelnut accessions, including those from recent collections in northern Spain, Turkey, Georgia and Azerbaijan. A total of 170 new single-locus polymorphic SSR primers were developed in hazelnut: 76 from a library enriched for GA repeats, 13 from a library enriched for CA repeats, 23 from internal repeats in cloned inter simple sequence repeats (ISSR) fragments, 52 from repeats at the ends of ISSR fragments, and 6 from Betulaceae sequences in GenBank. These polymorphic loci were characterized using 50 hazelnut accessions, including the parents of a mapping population and 48 accessions that represented the high level of genetic diversity in European hazelnut. One hundred forty three of the new polymorphic SSR loci were mapped in a full-sib population. The map of the resistant parent consists of 344 markers (175 random amplified polymorphic DNA (RAPD) markers and 169 SSRs) spanning 837 cM with an average of 2.43 cM between markers, while the map of the susceptible parent consists of 366 markers (183 RAPDs and 183 SSRs) spanning 926 cM with an average of 2.53 cM between markers. SRR locus A601 co-segregated with the S-locus that controls pollen-stigma incompatibility, and four loci (B774, B720, B760, and SSR62) were tightly linked to the S-locus (≤6 cM). Five loci (B716, B776, SSR9, SSR28, and SSR 100) were placed on linkage group 6 with the 'Gasaway' gene for resistance to eastern filbert blight. The Betula genes BpMADS2 and BetV1 and a Corylus lipoxygenase (LOX) gene were also placed on the hazelnut genetic map. A high percentage of loci (26.5%) gave poor fit to Mendelian expectation. Transferability of 66 Corylus and 52 Betula SSR primer pairs was studied by amplifying 69 accessions representing diverse taxa in the family Betulaceae. The transferability of 157 additional SSR loci developed from Corylus was investigated using 32 Betulaceae accessions. Transferability across species was 92.31%, while across genera in the Betulaceae it was 40.90%. The highest transferability across genera was 58.72% between Betula and Alnus. For the Corylus loci, transferability across species averaged 93.95% and across genera averaged 42.16%. The highest cross-genera amplification was 58.72% in Carpinus species. Using 12 microsatellite loci, genetic diversity was investigated in hazelnut accessions from Turkey, Georgia and Azerbaijan and compared to cultivars in the Italian-Spanish cluster. A high level of genetic diversity (H₀ = 0.69) in the cultivars from Turkey, Georgia and Azerbaijan was observed. A moderate shift in allelic frequencies (FST = 0.11 to 0.13) was seen between accessions from these three countries and the Italian-Spanish accessions, with accessions from the Black Sea and Caucasus tending to form subgroups by country of origin. The same 12 microsatellite loci were used to investigate genetic diversity in 69 hazelnut accessions collected in northern Spain. Of these, 50 had fingerprints identical to 'Casina', while the remaining 19 were unique and highly diverse. Genotyping profiles were produced for 160 additional accessions using the twelve dozen SSR loci. Title: Simple sequence repeat marker development and use in European hazelnut(Corylus avellana L.) Author: Gurcan, Kahraman New highly polymorphic simple sequence repeat (SSR) markers for European hazelnut (Corylus avellana L.). were developed from several sources. The markers were characterized, and segregation in a mapping population allowed to assign them to linkage groups. Their transferability across genera and species in the Betulaceae family was investigated. SSR markers were used to fingerprint several hazelnut accessions, including those from recent collections in northern Spain, Turkey, Georgia and Azerbaijan. A total of 170 new single-locus polymorphic SSR primers were developed in hazelnut: 76 from a library enriched for GA repeats, 13 from a library enriched for CA repeats, 23 from internal repeats in cloned inter simple sequence repeats (ISSR) fragments, 52 from repeats at the ends of ISSR fragments, and 6 from Betulaceae sequences in GenBank. These polymorphic loci were characterized using 50 hazelnut accessions, including the parents of a mapping population and 48 accessions that represented the high level of genetic diversity in European hazelnut. One hundred forty three of the new polymorphic SSR loci were mapped in a full-sib population. The map of the resistant parent consists of 344 markers (175 random amplified polymorphic DNA (RAPD) markers and 169 SSRs) spanning 837 cM with an average of 2.43 cM between markers, while the map of the susceptible parent consists of 366 markers (183 RAPDs and 183 SSRs) spanning 926 cM with an average of 2.53 cM between markers. SRR locus A601 co-segregated with the S-locus that controls pollen-stigma incompatibility, and four loci (B774, B720, B760, and SSR62) were tightly linked to the S-locus (≤6 cM). Five loci (B716, B776, SSR9, SSR28, and SSR 100) were placed on linkage group 6 with the 'Gasaway' gene for resistance to eastern filbert blight. The Betula genes BpMADS2 and BetV1 and a Corylus lipoxygenase (LOX) gene were also placed on the hazelnut genetic map. A high percentage of loci (26.5%) gave poor fit to Mendelian expectation. Transferability of 66 Corylus and 52 Betula SSR primer pairs was studied by amplifying 69 accessions representing diverse taxa in the family Betulaceae. The transferability of 157 additional SSR loci developed from Corylus was investigated using 32 Betulaceae accessions. Transferability across species was 92.31%, while across genera in the Betulaceae it was 40.90%. The highest transferability across genera was 58.72% between Betula and Alnus. For the Corylus loci, transferability across species averaged 93.95% and across genera averaged 42.16%. The highest cross-genera amplification was 58.72% in Carpinus species. Using 12 microsatellite loci, genetic diversity was investigated in hazelnut accessions from Turkey, Georgia and Azerbaijan and compared to cultivars in the Italian-Spanish cluster. A high level of genetic diversity (H₀ = 0.69) in the cultivars from Turkey, Georgia and Azerbaijan was observed. A moderate shift in allelic frequencies (FST = 0.11 to 0.13) was seen between accessions from these three countries and the Italian-Spanish accessions, with accessions from the Black Sea and Caucasus tending to form subgroups by country of origin. The same 12 microsatellite loci were used to investigate genetic diversity in 69 hazelnut accessions collected in northern Spain. Of these, 50 had fingerprints identical to 'Casina', while the remaining 19 were unique and highly diverse. Genotyping profiles were produced for 160 additional accessions using the twelve dozen SSR loci. Close

• 89. [Article] Magmatic processes beneath mid-ocean ridges : insights from mineral and glass chemistry in plagioclase ultraphyric basalts

  Prior to eruption at mid-ocean ridges, melts must travel through >6 km of crust from their origin in the mantle. The final composition of the melts is dependent on both the melting conditions and magmatic ...

  Citation × Citation Citation Abstract Copy Title: Magmatic processes beneath mid-ocean ridges : insights from mineral and glass chemistry in plagioclase ultraphyric basalts Author: Lange, Amy E. Prior to eruption at mid-ocean ridges, melts must travel through >6 km of crust from their origin in the mantle. The final composition of the melts is dependent on both the melting conditions and magmatic processes within the crust. While mid-ocean ridge basalt (MORB) glasses are commonly used to infer melting conditions, including upper mantle composition, extent of melting and melt aggregation, evidence suggests that the final erupted MORB melt is significantly affected by magma mixing, fractionation, and melt-wallrock interactions, which significantly alter the original composition of the melt. A yet unresolved problem in interpreted erupted basaltic glass is the relative role of mantle processes and crustal processes in their contribution to MORB. The three manuscripts in this dissertation use plagioclase phenocrysts in plagioclase ultraphyric basalts (PUBs) to attempt to address the nature of the magmatic processes occurring within the oceanic crust prior to eruption. Plagioclase megacrysts and host glasses were analyzed for Sr-isotopic compositions in multiple samples from multiple spreading ridges. The resultant data reveals that the plagioclase megacrysts are often in isotopic disequilibrium with the melt they are erupted in. Some of the samples also display significant inter- and intra-crystalline disequilibria. As Cl concentrations in melt inclusions were low, the observed isotopic heterogeneity cannot be caused by interaction with seawater. Rather, the varied Sr-isotopes in plagioclase are the result of growth from distinct mantle components and some physical process is responsible for entraining the plagioclase into the final melt. To better interpret this isotopic disequilibria recorded in plagioclase, this physical process which is responsible for the eruption of these plagioclase-rich magmas must be understood. No systematic difference exists between the lavas that erupt abundant plagioclase phenocrysts and those lavas from the same ridge segments that are aphyric. Because these plagioclase crystals are typically high anorthite (>An₈₀), the phenocrysts are typically more dense than the melt they are erupted in. Thus a simple floatation model is not sufficient to explain the eruption of PUBs. PUBs only erupt in locations without currently imaged magma chambers, mainly fast spreading ridges, because prolonged residence in a magma chamber would cause the dense plagioclase to settle out. PUBs may erupt, however, when magmas carrying plagioclase crystals travel through conduits without magma chambers and do not stall in the crust for extended periods of time. Finally, the plagioclase megacrysts in this study were analyzed for trace element concentrations, in addition to melt inclusions, olivine and host glass analyses. Collection of this suite of data allows for a more complete representation of the pre-eruptive history of individual basalts. Using appropriate partition coefficients for anorthitic plagioclase, liquids that were in trace element equilibrium with the megacrysts can be calculated and then compared to the array of lavas that are erupted on the surface. Liquids in equilibrium with plagioclase are more primitive than erupted MORB glasses in the same region and are typically not parental to the host lava in which the megacrysts were erupted. These primitive liquids often appear to be parental to other erupted lavas by fractional crystallization alone. Plagioclase equilibrium liquids that cannot be modeled as parental to the host lava are typically display isotopic disequilibrium as well. For samples that display trace element heterogeneity, many of the liquids in equilibrium with plagioclase can be modeled as resulting from progressive melting of a single mantle source. Title: Magmatic processes beneath mid-ocean ridges : insights from mineral and glass chemistry in plagioclase ultraphyric basalts Author: Lange, Amy E. Prior to eruption at mid-ocean ridges, melts must travel through >6 km of crust from their origin in the mantle. The final composition of the melts is dependent on both the melting conditions and magmatic processes within the crust. While mid-ocean ridge basalt (MORB) glasses are commonly used to infer melting conditions, including upper mantle composition, extent of melting and melt aggregation, evidence suggests that the final erupted MORB melt is significantly affected by magma mixing, fractionation, and melt-wallrock interactions, which significantly alter the original composition of the melt. A yet unresolved problem in interpreted erupted basaltic glass is the relative role of mantle processes and crustal processes in their contribution to MORB. The three manuscripts in this dissertation use plagioclase phenocrysts in plagioclase ultraphyric basalts (PUBs) to attempt to address the nature of the magmatic processes occurring within the oceanic crust prior to eruption. Plagioclase megacrysts and host glasses were analyzed for Sr-isotopic compositions in multiple samples from multiple spreading ridges. The resultant data reveals that the plagioclase megacrysts are often in isotopic disequilibrium with the melt they are erupted in. Some of the samples also display significant inter- and intra-crystalline disequilibria. As Cl concentrations in melt inclusions were low, the observed isotopic heterogeneity cannot be caused by interaction with seawater. Rather, the varied Sr-isotopes in plagioclase are the result of growth from distinct mantle components and some physical process is responsible for entraining the plagioclase into the final melt. To better interpret this isotopic disequilibria recorded in plagioclase, this physical process which is responsible for the eruption of these plagioclase-rich magmas must be understood. No systematic difference exists between the lavas that erupt abundant plagioclase phenocrysts and those lavas from the same ridge segments that are aphyric. Because these plagioclase crystals are typically high anorthite (>An₈₀), the phenocrysts are typically more dense than the melt they are erupted in. Thus a simple floatation model is not sufficient to explain the eruption of PUBs. PUBs only erupt in locations without currently imaged magma chambers, mainly fast spreading ridges, because prolonged residence in a magma chamber would cause the dense plagioclase to settle out. PUBs may erupt, however, when magmas carrying plagioclase crystals travel through conduits without magma chambers and do not stall in the crust for extended periods of time. Finally, the plagioclase megacrysts in this study were analyzed for trace element concentrations, in addition to melt inclusions, olivine and host glass analyses. Collection of this suite of data allows for a more complete representation of the pre-eruptive history of individual basalts. Using appropriate partition coefficients for anorthitic plagioclase, liquids that were in trace element equilibrium with the megacrysts can be calculated and then compared to the array of lavas that are erupted on the surface. Liquids in equilibrium with plagioclase are more primitive than erupted MORB glasses in the same region and are typically not parental to the host lava in which the megacrysts were erupted. These primitive liquids often appear to be parental to other erupted lavas by fractional crystallization alone. Plagioclase equilibrium liquids that cannot be modeled as parental to the host lava are typically display isotopic disequilibrium as well. For samples that display trace element heterogeneity, many of the liquids in equilibrium with plagioclase can be modeled as resulting from progressive melting of a single mantle source. Close

• 90. [Article] Meeting of the magmas : the evolutionary history of the Kalama Eruptive Period, Mount St. Helens, Washington

  Comprehension of eruptive histories is critical in understanding the evolution of magmatic systems at arc volcanoes and may supply evidence to the petrogenesis of intermediate and evolved magmas. Within ...

  Citation × Citation Citation Abstract Copy Title: Meeting of the magmas : the evolutionary history of the Kalama Eruptive Period, Mount St. Helens, Washington Author: Lieuallen, Athena Erin Comprehension of eruptive histories is critical in understanding the evolution of magmatic systems at arc volcanoes and may supply evidence to the petrogenesis of intermediate and evolved magmas. Within the 300 ka eruptive history of Mount St. Helens, Washington, the Kalama Eruptive Period, 1479- ~1750 CE was bracketed by interludes of quiescence (Hoblitt et al., 1980) and thus likely represents an entire eruptive cycle within a span of 300 years. Study of the magmatic evolution during this short time period provides key information regarding inputs and the plumbing system of Mount St. Helens. This research aims to enhance comprehension of processes leading to the petrogenesis of intermediate magmas by providing whole rock and phase geochemical data of an eruptive cycle, thereby providing constraints on the magmatic evolution of the Kalama Eruptive Period. The eruptive sequence is divided into early, middle and late subperiods. The early Kalama began with two dacitic plinian eruptions and continued with smaller eruptions of dacite domes (64.4-66.5 wt% SiO₂) that included quenched mafic inclusions (53.7-57.7 wt% SiO₂). The middle Kalama signified the onset of basaltic andesite and andesite eruptions ranging between 55.5-58.5 wt % SiO₂. Subsequently, summit domes that began as felsic andesite (61-62.5 wt% SiO₂) and transitioned to dacite (62.5-64.6 wt% SiO₂) dominated the late Kalama. Previous work on Kalama-aged rocks suggests magma mixing is an integral process in their production. Compositions and textures of crystal phases, in addition to the presence of xenocrysts in middle and late Kalama rocks, confirm mechanical mixing of magmas likely produced many of the sampled compositions. New petrographic observations were integrated with new whole rock and phase EMP and LA-ICP-MS data and the known stratigraphy in order to constrain the magmatic and crustal components active during the Kalama Eruptive Period. New findings include: 1. Two populations of quenched mafic inclusions, one olivine-rich and one olivine-poor, are identified from the early Kalama based on mineralogy, textures, and major and trace element chemistry. Major element modeling shows crustal anatexis of plutonic inclusions found in early Kalama dacites could produce the felsic magma source of the olivine-poor population. The olivine-rich population incorporated cumulate material. 2. Four distinct lava populations erupted during the early part of the middle Kalama (X lavas), including two found exclusively in lahar deposits: M-type lahars are the most mafic, B-type lahars are more mixed, the Two Finger Flow was previously grouped with other middle Kalama-age lavas, and the X lava (in situ) has unique geochemical and textural character. X tephras likely correlate with the lavas. 3. There were at least three mafic source contributions at Mount St. Helens during the eruptive period: the parent to the X deposits, the cumulate material in the olivine-rich QMIs, and the calc-alkaline parent to the MKLV and SDO. The magma reservoir at Mount St. Helens has been modeled as a single, elongate chamber (Pallister et al., 1992). Multiple coeval basaltic or basaltic andesite parents fluxing into the magmatic system beneath the volcano could indicate a more complex magma chamber structure. Title: Meeting of the magmas : the evolutionary history of the Kalama Eruptive Period, Mount St. Helens, Washington Author: Lieuallen, Athena Erin Comprehension of eruptive histories is critical in understanding the evolution of magmatic systems at arc volcanoes and may supply evidence to the petrogenesis of intermediate and evolved magmas. Within the 300 ka eruptive history of Mount St. Helens, Washington, the Kalama Eruptive Period, 1479- ~1750 CE was bracketed by interludes of quiescence (Hoblitt et al., 1980) and thus likely represents an entire eruptive cycle within a span of 300 years. Study of the magmatic evolution during this short time period provides key information regarding inputs and the plumbing system of Mount St. Helens. This research aims to enhance comprehension of processes leading to the petrogenesis of intermediate magmas by providing whole rock and phase geochemical data of an eruptive cycle, thereby providing constraints on the magmatic evolution of the Kalama Eruptive Period. The eruptive sequence is divided into early, middle and late subperiods. The early Kalama began with two dacitic plinian eruptions and continued with smaller eruptions of dacite domes (64.4-66.5 wt% SiO₂) that included quenched mafic inclusions (53.7-57.7 wt% SiO₂). The middle Kalama signified the onset of basaltic andesite and andesite eruptions ranging between 55.5-58.5 wt % SiO₂. Subsequently, summit domes that began as felsic andesite (61-62.5 wt% SiO₂) and transitioned to dacite (62.5-64.6 wt% SiO₂) dominated the late Kalama. Previous work on Kalama-aged rocks suggests magma mixing is an integral process in their production. Compositions and textures of crystal phases, in addition to the presence of xenocrysts in middle and late Kalama rocks, confirm mechanical mixing of magmas likely produced many of the sampled compositions. New petrographic observations were integrated with new whole rock and phase EMP and LA-ICP-MS data and the known stratigraphy in order to constrain the magmatic and crustal components active during the Kalama Eruptive Period. New findings include: 1. Two populations of quenched mafic inclusions, one olivine-rich and one olivine-poor, are identified from the early Kalama based on mineralogy, textures, and major and trace element chemistry. Major element modeling shows crustal anatexis of plutonic inclusions found in early Kalama dacites could produce the felsic magma source of the olivine-poor population. The olivine-rich population incorporated cumulate material. 2. Four distinct lava populations erupted during the early part of the middle Kalama (X lavas), including two found exclusively in lahar deposits: M-type lahars are the most mafic, B-type lahars are more mixed, the Two Finger Flow was previously grouped with other middle Kalama-age lavas, and the X lava (in situ) has unique geochemical and textural character. X tephras likely correlate with the lavas. 3. There were at least three mafic source contributions at Mount St. Helens during the eruptive period: the parent to the X deposits, the cumulate material in the olivine-rich QMIs, and the calc-alkaline parent to the MKLV and SDO. The magma reservoir at Mount St. Helens has been modeled as a single, elongate chamber (Pallister et al., 1992). Multiple coeval basaltic or basaltic andesite parents fluxing into the magmatic system beneath the volcano could indicate a more complex magma chamber structure. Close