Categorization of locations with similar environments helps breeders to efficiently utilize resou... more Categorization of locations with similar environments helps breeders to efficiently utilize resources and effectively target germplasm. This study was conducted to determine the relationship among winter wheat (Triticum aestivum L.) yield testing locations in South Dakota. Yield trial data containing 14 locations and 38 genotypes from 8 year were analyzed for crossover genotype (G) × environment (E) interactions according to the Azzalini-Cox test. G × E was significant (P < 0.05) and contributed a small proportion of variation over the total phenotypic variation. This suggested that for efficient resource utilization, locations should be clustered. The data were further analyzed using the Shifted Multiplicative Model (SHMM), Spearman’s rank correlation and GGE biplot to group testing locations based on yield. SHMM analysis revealed four major cluster groups in which the first and third had three locations, with four locations in each of the second and fourth groups. Spearman rank correlations between locations within groups were significant and positive. GGE biplot analysis revealed two major mega-environments of winter wheat testing locations in South Dakota. Oelrichs was the best testing location and XH1888 was the highest yielding genotype. SHMM, rank correlation and GGE biplot analyses showed that the locations of Martin and Winner in the second group and Highmore, Oelrichs and Wall in the third group were similar. This indicated that the number of testing locations could be reduced without much loss of grain yield information. GGE biplot provided additional information on the performance of entries and locations. SHMM clustered locations with reduced cross-over interaction of genotype × location. The combined methods used in this study provided valuable information on categorization of locations with similar environments for efficient resource allocation. This information should facilitate efficient targeting of breeding and testing efforts, especially in large breeding programs.
Fusarium head blight (FHB) negatively impacts grain yield and quality of wheat (Triticum aestivum... more Fusarium head blight (FHB) negatively impacts grain yield and quality of wheat (Triticum aestivum L. em. Thell) worldwide, especially when warm, humid weather prevails during flowering and grain filling. Our objective was to determine the mechanism of genetic control of FHB resistance in selected winter and spring wheat germplasm. Six genotypes, ‘Nekota’ (A), ‘2137’ (B), ‘Harding’ (C), ‘Ning7840’ (D), ‘ND2710’
Much effort has been invested in identifying molecular markers in wheat (Triticum aestivum L.) li... more Much effort has been invested in identifying molecular markers in wheat (Triticum aestivum L.) linked to quantitative trait loci (QTL) that confer resistance to Fusarium head blight (FHB) caused by Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein) Petch]. Even after several generations of crossing and selection by many wheat breeding programs, resistance of the Chinese spring wheat cultivar ‘Sumai 3’ (PI 481542) remains among the most effective. It therefore seems that undocumented resistance QTL present in Sumai 3 were not detected in various mapping studies. Using an extremely susceptible Tibetan landrace (‘Y1193-6’; unknown pedigree) in the creation of a mapping population with Sumai 3, the objective of this research was to identify undocumented resistance QTL in Sumai 3. This was accomplished through collecting disease index (DI) and Fusarium damaged kernel (FDK) phenotypic values along with 305 Diversity Array Technology (DArT) and 52 Simple Sequence Repeat (SSR) marker genotypes on 160 F2:6 recombinant inbred lines (RILs). Disease response evaluations were based on four (two greenhouse and two field) experiments where spray inoculation methods were used. Three QTL were identified on chromosome arms 3BS, 6BL and 2DS explaining 26.1, 10.7 and 18.9% of the phenotypic variation for DI, respectively. The same QTL were also significantly associated with reduced FDK scores and explained 28.0, 11.0 and 23.0% of phenotypic variation. Lines within the mapping population were placed in eight categories with respect to their various QTL combinations. Lines with no QTL were the most susceptible, whereas those with the Sumai 3-derived 3BS and 6BL QTL combined with the 2DS QTL from Y1193-6 were the most resistant. Though the 3BS and 6BL QTL are well-documented, the 2DS resistance QTL, which was contributed by the susceptible parent, confers increased susceptibility when derived from Sumai 3. In this study no new FHB QTL from Sumai 3 was discovered, but results suggest that Sumai 3 contains a QTL for susceptibility on chromosome arm 2DS. Selection against this QTL may potentially increase resistance levels among Sumai 3-derived populations.
The Long Island Sound Coastal Observational platform (LISCO) near Northport, New York, has been r... more The Long Island Sound Coastal Observational platform (LISCO) near Northport, New York, has been recently established to support satellite data validation. LISCO is equipped with both multispectral SeaPRISM and hyperspectral HyperSAS radiometers for ocean color measurements. LISCO substantially expands observational capabilities for the continuous monitoring and assessment of ocean color satellite data quality. This offers the potential for improving the calibration and validation activities of current and future Ocean Color satellite missions, as well as for satellite intercomparisons and spectral characterization of coastal waters. Results of measurements made by both the multi and hyperspectral instruments, in operation since October 2009, are presented, evaluated and compared with ocean color satellite data. The comparisons with the normalized water-leaving radiance derived from SeaPRISM with that from MERIS, MODIS and SeaWiFS showed satisfactory correlations (r > 0.9 at 550nm) and consistencies (APD < 15% at 550nm). Similar and equivalent results are obtained when the hyperspectral HYPERSAS data are compared with the same satellite datasets. The results confirm that the LISCO site is appropriate for use in calibration/validation of the ocean color satellites in coastal waters and as a key element of the AERONET-OC network. This makes it possible to foresee a wider use of the LISCO site to monitor current and future ocean color multispectral (NPOESS, Sentinel) and hyperspectral (HICO) satellite missions.
The degree of polarization (DOP) of the underwater light field in oceanic waters is, as follows f... more The degree of polarization (DOP) of the underwater light field in oceanic waters is, as follows from the vector radiative transfer equation and has been shown experimentally for a long time [1], related to the single scattering albedo of suspended particles. The single scattering albedo, in turn, is given by the ratio of the scattering coefficient to the attenuation coefficient (or 1 - the ratio of the absorption coefficient to the attenuation coefficient). Knowledge of the single scattering albedo and of the particulate scattering matrix permits solution of the radiative transfer equation for the ocean body. This then opens up the possibility for estimation of attenuation coefficients from measurements of the Stokes components of the upwelling underwater light field which is not possible from unpolarized measurements of the remote sensing reflectance. Results of radiative transfer calculations are presented. We simulated multiple underwater polarized light fields (for the whole visible spectrum) using a vector radiative transfer code with the purpose of obtaining a parameterization of this relationship for different viewing geometries (different solar and zenith/azimuth viewing angles) and in various water conditions (i.e. various IOPs).
Measurements of light intensity, often from space borne sensors, have been used to investigate th... more Measurements of light intensity, often from space borne sensors, have been used to investigate the optical properties of the constituents of Earth's ecosystem. In ocean color research, water-leaving radiance can give useful information about inherent optical properties (IOPs). Additional consideration of polarization of the water-leaving radiance can lead to a better understanding of the physical and optical characteristics of the water body. Polarization properties strongly depend on particle microphysics, such as refractive index, effective radius, size distribution, and single scattering albedo. Using radiative transfer simulations of the polarized light field for various ranges of water constituents, we were able to develop relationships between the degree of polarization (DOP) and the ratio of hydrosol absorption to attenuation coefficient. This relationship was then studied for different viewing geometries of the polarized light and for different sun positions. A Neural Network sensitivity analysis was also performed to better understand the dependence of DOP on microphysical parameters.
Categorization of locations with similar environments helps breeders to efficiently utilize resou... more Categorization of locations with similar environments helps breeders to efficiently utilize resources and effectively target germplasm. This study was conducted to determine the relationship among winter wheat (Triticum aestivum L.) yield testing locations in South Dakota. Yield trial data containing 14 locations and 38 genotypes from 8 year were analyzed for crossover genotype (G) × environment (E) interactions according to the Azzalini-Cox test. G × E was significant (P < 0.05) and contributed a small proportion of variation over the total phenotypic variation. This suggested that for efficient resource utilization, locations should be clustered. The data were further analyzed using the Shifted Multiplicative Model (SHMM), Spearman’s rank correlation and GGE biplot to group testing locations based on yield. SHMM analysis revealed four major cluster groups in which the first and third had three locations, with four locations in each of the second and fourth groups. Spearman rank correlations between locations within groups were significant and positive. GGE biplot analysis revealed two major mega-environments of winter wheat testing locations in South Dakota. Oelrichs was the best testing location and XH1888 was the highest yielding genotype. SHMM, rank correlation and GGE biplot analyses showed that the locations of Martin and Winner in the second group and Highmore, Oelrichs and Wall in the third group were similar. This indicated that the number of testing locations could be reduced without much loss of grain yield information. GGE biplot provided additional information on the performance of entries and locations. SHMM clustered locations with reduced cross-over interaction of genotype × location. The combined methods used in this study provided valuable information on categorization of locations with similar environments for efficient resource allocation. This information should facilitate efficient targeting of breeding and testing efforts, especially in large breeding programs.
Fusarium head blight (FHB) negatively impacts grain yield and quality of wheat (Triticum aestivum... more Fusarium head blight (FHB) negatively impacts grain yield and quality of wheat (Triticum aestivum L. em. Thell) worldwide, especially when warm, humid weather prevails during flowering and grain filling. Our objective was to determine the mechanism of genetic control of FHB resistance in selected winter and spring wheat germplasm. Six genotypes, ‘Nekota’ (A), ‘2137’ (B), ‘Harding’ (C), ‘Ning7840’ (D), ‘ND2710’
Much effort has been invested in identifying molecular markers in wheat (Triticum aestivum L.) li... more Much effort has been invested in identifying molecular markers in wheat (Triticum aestivum L.) linked to quantitative trait loci (QTL) that confer resistance to Fusarium head blight (FHB) caused by Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein) Petch]. Even after several generations of crossing and selection by many wheat breeding programs, resistance of the Chinese spring wheat cultivar ‘Sumai 3’ (PI 481542) remains among the most effective. It therefore seems that undocumented resistance QTL present in Sumai 3 were not detected in various mapping studies. Using an extremely susceptible Tibetan landrace (‘Y1193-6’; unknown pedigree) in the creation of a mapping population with Sumai 3, the objective of this research was to identify undocumented resistance QTL in Sumai 3. This was accomplished through collecting disease index (DI) and Fusarium damaged kernel (FDK) phenotypic values along with 305 Diversity Array Technology (DArT) and 52 Simple Sequence Repeat (SSR) marker genotypes on 160 F2:6 recombinant inbred lines (RILs). Disease response evaluations were based on four (two greenhouse and two field) experiments where spray inoculation methods were used. Three QTL were identified on chromosome arms 3BS, 6BL and 2DS explaining 26.1, 10.7 and 18.9% of the phenotypic variation for DI, respectively. The same QTL were also significantly associated with reduced FDK scores and explained 28.0, 11.0 and 23.0% of phenotypic variation. Lines within the mapping population were placed in eight categories with respect to their various QTL combinations. Lines with no QTL were the most susceptible, whereas those with the Sumai 3-derived 3BS and 6BL QTL combined with the 2DS QTL from Y1193-6 were the most resistant. Though the 3BS and 6BL QTL are well-documented, the 2DS resistance QTL, which was contributed by the susceptible parent, confers increased susceptibility when derived from Sumai 3. In this study no new FHB QTL from Sumai 3 was discovered, but results suggest that Sumai 3 contains a QTL for susceptibility on chromosome arm 2DS. Selection against this QTL may potentially increase resistance levels among Sumai 3-derived populations.
The Long Island Sound Coastal Observational platform (LISCO) near Northport, New York, has been r... more The Long Island Sound Coastal Observational platform (LISCO) near Northport, New York, has been recently established to support satellite data validation. LISCO is equipped with both multispectral SeaPRISM and hyperspectral HyperSAS radiometers for ocean color measurements. LISCO substantially expands observational capabilities for the continuous monitoring and assessment of ocean color satellite data quality. This offers the potential for improving the calibration and validation activities of current and future Ocean Color satellite missions, as well as for satellite intercomparisons and spectral characterization of coastal waters. Results of measurements made by both the multi and hyperspectral instruments, in operation since October 2009, are presented, evaluated and compared with ocean color satellite data. The comparisons with the normalized water-leaving radiance derived from SeaPRISM with that from MERIS, MODIS and SeaWiFS showed satisfactory correlations (r > 0.9 at 550nm) and consistencies (APD < 15% at 550nm). Similar and equivalent results are obtained when the hyperspectral HYPERSAS data are compared with the same satellite datasets. The results confirm that the LISCO site is appropriate for use in calibration/validation of the ocean color satellites in coastal waters and as a key element of the AERONET-OC network. This makes it possible to foresee a wider use of the LISCO site to monitor current and future ocean color multispectral (NPOESS, Sentinel) and hyperspectral (HICO) satellite missions.
The degree of polarization (DOP) of the underwater light field in oceanic waters is, as follows f... more The degree of polarization (DOP) of the underwater light field in oceanic waters is, as follows from the vector radiative transfer equation and has been shown experimentally for a long time [1], related to the single scattering albedo of suspended particles. The single scattering albedo, in turn, is given by the ratio of the scattering coefficient to the attenuation coefficient (or 1 - the ratio of the absorption coefficient to the attenuation coefficient). Knowledge of the single scattering albedo and of the particulate scattering matrix permits solution of the radiative transfer equation for the ocean body. This then opens up the possibility for estimation of attenuation coefficients from measurements of the Stokes components of the upwelling underwater light field which is not possible from unpolarized measurements of the remote sensing reflectance. Results of radiative transfer calculations are presented. We simulated multiple underwater polarized light fields (for the whole visible spectrum) using a vector radiative transfer code with the purpose of obtaining a parameterization of this relationship for different viewing geometries (different solar and zenith/azimuth viewing angles) and in various water conditions (i.e. various IOPs).
Measurements of light intensity, often from space borne sensors, have been used to investigate th... more Measurements of light intensity, often from space borne sensors, have been used to investigate the optical properties of the constituents of Earth's ecosystem. In ocean color research, water-leaving radiance can give useful information about inherent optical properties (IOPs). Additional consideration of polarization of the water-leaving radiance can lead to a better understanding of the physical and optical characteristics of the water body. Polarization properties strongly depend on particle microphysics, such as refractive index, effective radius, size distribution, and single scattering albedo. Using radiative transfer simulations of the polarized light field for various ranges of water constituents, we were able to develop relationships between the degree of polarization (DOP) and the ratio of hydrosol absorption to attenuation coefficient. This relationship was then studied for different viewing geometries of the polarized light and for different sun positions. A Neural Network sensitivity analysis was also performed to better understand the dependence of DOP on microphysical parameters.
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