Sixteen faba bean genotypes were evaluated in 13 environments in Ethiopia during the main cropping season for three years(2009–2011). The objectives of the study were to evaluate the yield stability of the genotypes ...Sixteen faba bean genotypes were evaluated in 13 environments in Ethiopia during the main cropping season for three years(2009–2011). The objectives of the study were to evaluate the yield stability of the genotypes and the relative importance of different stability parameters for improving selection in faba bean. The study was conducted using a randomized complete block design with four replications. G × E interaction and yield stability were estimated using 17 different stability parameters. Pooled analysis of variance for grain yield showed that the main effects of both genotypes and environments, and the interaction effect, were highly significant(P ≤ 0.001) and(P ≤ 0.01), respectively. The environment main effect accounted for 89.27% of the total yield variation, whereas genotype and G × E interaction effects accounted for 2.12% and 3.31%, respectively.Genotypic superiority index(Pi) and FT3 were found to be very informative for selecting both high-yielding and stable faba bean genotypes. Twelve of the 17 stability parameters,including CVi, RS, α, λ, S2 di, bi, S(2)i, Wi, σ2i, EV, P59, and ASV, were influenced simultaneously by both yield and stability. They should accordingly be used as complementary criteria to select genotypes with high yield and stability. Although none of the varieties showed consistently superior performance across all environments, the genotype EK 01024-1-2ranked in the top third of the test entries in 61.5% of the test environments and was identified as the most stable genotype, with type I stability. EK 01024-1-2 also showed a17.0% seed size advantage over the standard varieties and was released as a new variety in2013 for wide production and named "Gora". Different stability parameters explained genotypic performance differently, irrespective of yield performance. It was accordingly concluded that assessment of G × E interaction and yield stability should not be based on a single or a few stability parameters but rather on a combination of stability parameters.展开更多
Maize stalk rot reduces grain yield and quality.Information about the genetics of resistance to maize stalk rot could help breeders design effective breeding strategies for the trait.Genomic prediction may be a more e...Maize stalk rot reduces grain yield and quality.Information about the genetics of resistance to maize stalk rot could help breeders design effective breeding strategies for the trait.Genomic prediction may be a more effective breeding strategy for stalk-rot resistance than marker-assisted selection.We performed a genome-wide association study(GWAS)and genomic prediction of resistance in testcross hybrids of 677 inbred lines from the Tuxpe?o and non-Tuxpe?o heterotic pools grown in three environments and genotyped with 200,681 single-nucleotide polymorphisms(SNPs).Eighteen SNPs associated with stalk rot shared genomic regions with gene families previously associated with plant biotic and abiotic responses.More favorable SNP haplotypes traced to tropical than to temperate progenitors of the inbred lines.Incorporating genotype-by-environment(G×E)interaction increased genomic prediction accuracy.展开更多
Plain weave woven glass fabric reinforced epoxy (G-E) composite filled with two different types of fillers namely graphite, silicon carbide (each 5 and 10 wt%) was fabricated by hand lay-up method and compressed using...Plain weave woven glass fabric reinforced epoxy (G-E) composite filled with two different types of fillers namely graphite, silicon carbide (each 5 and 10 wt%) was fabricated by hand lay-up method and compressed using hot press. These composites were investigated for their static mechanical properties such as tensile, flexural properties and impact strength as well as mode-I fracture toughness as per ASTM standards. Experimental results on mechanical properties indicate that the strength and the modulus in tensile and flexural mode for G-E composite increase with increasing filler loading. The unfilled G-E composite has the tensile strength of 305 MPa and increased to 404.2 MPa for 10 wt% silicon carbide. However, in three-point bend mode, addition of graphite in G-E showed the highest flexural strength as well as modulus. Mode-I fracture toughness test results indicated that the graphite filler loading improved the toughness of G-E composite. Selected failed samples under tensile, bending and mode-I fracture were examined using scanning electron microscope to identify the fracture features.展开更多
The aim of the research article is to study the mechanical and two-body abrasive wear behaviour of alumina (Al2O3) filled glass fabric reinforced epoxy (G-E) composites. Alumina filled G-E composites containing 0, 5, ...The aim of the research article is to study the mechanical and two-body abrasive wear behaviour of alumina (Al2O3) filled glass fabric reinforced epoxy (G-E) composites. Alumina filled G-E composites containing 0, 5, 7.5 and 10 wt% were prepared using the hand lay-up technique followed by compression molding. The mechanical properties such as tensile strength, hardness and tensile modulus were investigated in accordance with ASTM standards. Two-body abrasive wear studies were carried out using a pin-on-disc wear tester under multi-pass condition against the water proof silicon carbide abrasive paper. From the experimental investigation, it was found that the presence of?Al2O3 filler improved the tensile strength and tensile modulus of the G-E composite. Inclusion of Al2O3 filler reduced the specific wear rate of G-E composite. The results show that in abrasion mode, as the filler loading increases the wear volume decreases and increased with increasing abrading distance. The excellent wear resistance was obtained for Al2O3 filled G-E composites. Furthermore, 10 wt% filler loading gave a very less wear loss. Finally, the scanning electron microscopic observations on the wear mechanisms Al2O3 filled G-E composites was discussed.展开更多
Multifunctional hybrid polymer composites were projected as novel solutions to meet the demands in various industrial applications ranging from automotive to aerospace. This investigation focuses on processing, flexur...Multifunctional hybrid polymer composites were projected as novel solutions to meet the demands in various industrial applications ranging from automotive to aerospace. This investigation focuses on processing, flexural strength and fracture toughness characterization of the glass fabric reinforced epoxy (G-E) composites and graphite/fly ash cenosphere (FAC) modified interface between the epoxy matrix and glass fabric. Hand lay-up followed by compression moulding method was used to fabricate the laminates. Flexural and fracture toughness tests at room temperature, elevated temperature and cryogenic temperature were conducted to assess the flexural strength (FS) and mode-I plane-strain fracture toughness (K<sub>IC</sub>). The experimental and characterization efforts suggest that both graphite and FAC fillers improve bonding at the interface. The study showed that the graphite is more favorable for enhancing FS and KIC of G-E composites. Graphite filled G-E hybrid composites with significant FS and KIC to that of unfilled and FA filled G-E were successfully achieved by incorporating 10 wt% graphite. The incorporation of fillers resulted in improvement of FS, which increased by 43% and 37.7% for 10Gr+G-E and 10FAC+G-E hybrid composites respectively. All composites show a 26% improvement in KIC at cryogenic temperature and a decrease of 12.5% at elevated temperature. According to the SEM observations, fiber debonding from the matrix is suppressed due to the presence and uniform distribution of graphite. In addition, micro-pores, matrix shearing, active toughening mechanisms induced by graphite, such as crack deflection, layer breakage and delamination of graphite layers contributed to the enhanced KIC of hybrid G-E composites.展开更多
Since the room-temperature detector CdZnTe(CZT) has advantages in terms of detection efficiency,energy resolution, and size, it has been extensively used to detect X-rays and gamma-rays. So far, nuclear radiation dete...Since the room-temperature detector CdZnTe(CZT) has advantages in terms of detection efficiency,energy resolution, and size, it has been extensively used to detect X-rays and gamma-rays. So far, nuclear radiation detectors such as cerium chloride doped with lanthanum bromide(LaBr_3(Ce)), thallium doped with cesium iodide(sI(Tl)), thallium doped with sodium iodide(NaI(Tl)),and high-purity germanium(HPGe) primarily use the spectroscopy-dose rate function(G(E)) to achieve the accurate measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)). However, the spectroscopy-dose rate function has been rarely measured for a CZT detector. In this study, we performed spectrum measurement using a hemispherical CZT detector in a radiation protection standards laboratory. The spectroscopy-dose rate function G(E) of the CZT detector was calculated using the least-squares method combined with the standard dose rate at the measurement position. The results showed that the hemispherical CZT detector could complete the measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)) by using the G(E) function at energies between 48 keV and 1.25 MeV, and the relative intrinsic errors were, respectively, controlled within ± 2. 3 and ± 2. 1%.展开更多
Elucidation of the relationships between genetic polymorphisms and environmental exposures can provide insights into the pathways and mechanisms underlying complex traits. A new approach was used to detect G×E （...Elucidation of the relationships between genetic polymorphisms and environmental exposures can provide insights into the pathways and mechanisms underlying complex traits. A new approach was used to detect G×E （gene-environment） interactions involved in human skin pigmentation variation to better understand the adaptive evolution of skin pigmentation. Specifically, we used genetic engineering, remote UVR （ultraviolet radiation） sensing and GIS （geographic information systems） to integrate the analysis of genetic and environmental factors into a coherent biological framework. Since we expected to generate large datasets for this multidimensional analysis, we used PCA （principal components analysis） as a spatial statistical analysis technique for analyzing the G×E interactions. The results suggest that skin pigmentation may be affected by mutations induced by UVR and support the hypothesis that global variation in skin pigmentation may be the result of localized adaptation to different UVR conditions via natural selection. Analyzing the relationships between heterozygous frequencies for SNP （single nucleotide polymorphism） loci and seasonal UVR levels as the environment changes will help elucidate the selective mechanisms involved in the UVR-induced evolution of skin pigmentation. Skin pigmentation fulfills the criteria for a successful evolutionary G×E interactions model.展开更多
Aims While a growing number of studies have demonstrated the impor-tance of intraspecific differences within plant species on associ-ated arthropod communities,little is known regarding the relative strength of these ...Aims While a growing number of studies have demonstrated the impor-tance of intraspecific differences within plant species on associ-ated arthropod communities,little is known regarding the relative strength of these effects compared to environmental factors.In this study,we examined whether intraspecific plant differences and nutrient fertilization interact to shape the arthropod community of a dominant coastal shrub,Baccharis pilularis(coyote bush).Methods We overlaid a fertilization treatment on a 12-year-old common garden experiment planted with erect and prostrate architectural morphs of Baccharis in california,USA.to collect the associated arthropod community,we vacuum sampled the crown of each Baccharis and identified individuals to species or morphospecies.Important Findings We found that arthropod richness and abundance were 2-to 3-fold greater on prostrate Baccharis than on erect morphs,but observed no main effects of fertilizer addition on the over-all arthropod communities.Predators responded as strongly as herbivores to plant morph,and both were unaffected by nutrient additions.Only the specialist stem galler,Gnorimoschema bac-charisella,showed an interactive response to plant morph and fertilization.Nitrogen,phosphorous and potassium addition had opposite effects on the two morphs,increasing stem gall abun-dance by 50%on prostrate morphs,but reducing galling by 20%on erect morphs.the architectural complexity of prostrate morphs could be the driving mechanism of differences in arthropod assemblages.Overall,our results demonstrate that communitylevel consequences of intraspecific differences in plants are strong,rather than being context dependent,and are generally maintained under different resource environments.the growing number of studies showing strong genotype than nutrient effects on associated arthropod communities suggests that this might be a generalized pattern.展开更多
基金supported by the Ethiopian Institute of Agricultural Research
文摘Sixteen faba bean genotypes were evaluated in 13 environments in Ethiopia during the main cropping season for three years(2009–2011). The objectives of the study were to evaluate the yield stability of the genotypes and the relative importance of different stability parameters for improving selection in faba bean. The study was conducted using a randomized complete block design with four replications. G × E interaction and yield stability were estimated using 17 different stability parameters. Pooled analysis of variance for grain yield showed that the main effects of both genotypes and environments, and the interaction effect, were highly significant(P ≤ 0.001) and(P ≤ 0.01), respectively. The environment main effect accounted for 89.27% of the total yield variation, whereas genotype and G × E interaction effects accounted for 2.12% and 3.31%, respectively.Genotypic superiority index(Pi) and FT3 were found to be very informative for selecting both high-yielding and stable faba bean genotypes. Twelve of the 17 stability parameters,including CVi, RS, α, λ, S2 di, bi, S(2)i, Wi, σ2i, EV, P59, and ASV, were influenced simultaneously by both yield and stability. They should accordingly be used as complementary criteria to select genotypes with high yield and stability. Although none of the varieties showed consistently superior performance across all environments, the genotype EK 01024-1-2ranked in the top third of the test entries in 61.5% of the test environments and was identified as the most stable genotype, with type I stability. EK 01024-1-2 also showed a17.0% seed size advantage over the standard varieties and was released as a new variety in2013 for wide production and named "Gora". Different stability parameters explained genotypic performance differently, irrespective of yield performance. It was accordingly concluded that assessment of G × E interaction and yield stability should not be based on a single or a few stability parameters but rather on a combination of stability parameters.
基金funded by the CGIAR Research Program(CRP)on MAIZEthe USAID through the Accelerating Genetic Gains Supplemental Project(Amend.No.9 MTO 069033),and the One CGIAR Initiative on Accelerated Breeding+1 种基金funding from the governments of Australia,Belgium,Canada,China,France,India,Japan,the Republic of Korea,Mexico,the Netherlands,New Zealand,Norway,Sweden,Switzerland,the United Kingdom,the United States,and the World Banksupported by the China Scholarship Council。
文摘Maize stalk rot reduces grain yield and quality.Information about the genetics of resistance to maize stalk rot could help breeders design effective breeding strategies for the trait.Genomic prediction may be a more effective breeding strategy for stalk-rot resistance than marker-assisted selection.We performed a genome-wide association study(GWAS)and genomic prediction of resistance in testcross hybrids of 677 inbred lines from the Tuxpe?o and non-Tuxpe?o heterotic pools grown in three environments and genotyped with 200,681 single-nucleotide polymorphisms(SNPs).Eighteen SNPs associated with stalk rot shared genomic regions with gene families previously associated with plant biotic and abiotic responses.More favorable SNP haplotypes traced to tropical than to temperate progenitors of the inbred lines.Incorporating genotype-by-environment(G×E)interaction increased genomic prediction accuracy.
文摘Plain weave woven glass fabric reinforced epoxy (G-E) composite filled with two different types of fillers namely graphite, silicon carbide (each 5 and 10 wt%) was fabricated by hand lay-up method and compressed using hot press. These composites were investigated for their static mechanical properties such as tensile, flexural properties and impact strength as well as mode-I fracture toughness as per ASTM standards. Experimental results on mechanical properties indicate that the strength and the modulus in tensile and flexural mode for G-E composite increase with increasing filler loading. The unfilled G-E composite has the tensile strength of 305 MPa and increased to 404.2 MPa for 10 wt% silicon carbide. However, in three-point bend mode, addition of graphite in G-E showed the highest flexural strength as well as modulus. Mode-I fracture toughness test results indicated that the graphite filler loading improved the toughness of G-E composite. Selected failed samples under tensile, bending and mode-I fracture were examined using scanning electron microscope to identify the fracture features.
文摘The aim of the research article is to study the mechanical and two-body abrasive wear behaviour of alumina (Al2O3) filled glass fabric reinforced epoxy (G-E) composites. Alumina filled G-E composites containing 0, 5, 7.5 and 10 wt% were prepared using the hand lay-up technique followed by compression molding. The mechanical properties such as tensile strength, hardness and tensile modulus were investigated in accordance with ASTM standards. Two-body abrasive wear studies were carried out using a pin-on-disc wear tester under multi-pass condition against the water proof silicon carbide abrasive paper. From the experimental investigation, it was found that the presence of?Al2O3 filler improved the tensile strength and tensile modulus of the G-E composite. Inclusion of Al2O3 filler reduced the specific wear rate of G-E composite. The results show that in abrasion mode, as the filler loading increases the wear volume decreases and increased with increasing abrading distance. The excellent wear resistance was obtained for Al2O3 filled G-E composites. Furthermore, 10 wt% filler loading gave a very less wear loss. Finally, the scanning electron microscopic observations on the wear mechanisms Al2O3 filled G-E composites was discussed.
文摘Multifunctional hybrid polymer composites were projected as novel solutions to meet the demands in various industrial applications ranging from automotive to aerospace. This investigation focuses on processing, flexural strength and fracture toughness characterization of the glass fabric reinforced epoxy (G-E) composites and graphite/fly ash cenosphere (FAC) modified interface between the epoxy matrix and glass fabric. Hand lay-up followed by compression moulding method was used to fabricate the laminates. Flexural and fracture toughness tests at room temperature, elevated temperature and cryogenic temperature were conducted to assess the flexural strength (FS) and mode-I plane-strain fracture toughness (K<sub>IC</sub>). The experimental and characterization efforts suggest that both graphite and FAC fillers improve bonding at the interface. The study showed that the graphite is more favorable for enhancing FS and KIC of G-E composites. Graphite filled G-E hybrid composites with significant FS and KIC to that of unfilled and FA filled G-E were successfully achieved by incorporating 10 wt% graphite. The incorporation of fillers resulted in improvement of FS, which increased by 43% and 37.7% for 10Gr+G-E and 10FAC+G-E hybrid composites respectively. All composites show a 26% improvement in KIC at cryogenic temperature and a decrease of 12.5% at elevated temperature. According to the SEM observations, fiber debonding from the matrix is suppressed due to the presence and uniform distribution of graphite. In addition, micro-pores, matrix shearing, active toughening mechanisms induced by graphite, such as crack deflection, layer breakage and delamination of graphite layers contributed to the enhanced KIC of hybrid G-E composites.
基金supported by the National Key Scientific Instruments to Develop Dedicated(Nos.2013YQ090811 and 2016YFF0103800)
文摘Since the room-temperature detector CdZnTe(CZT) has advantages in terms of detection efficiency,energy resolution, and size, it has been extensively used to detect X-rays and gamma-rays. So far, nuclear radiation detectors such as cerium chloride doped with lanthanum bromide(LaBr_3(Ce)), thallium doped with cesium iodide(sI(Tl)), thallium doped with sodium iodide(NaI(Tl)),and high-purity germanium(HPGe) primarily use the spectroscopy-dose rate function(G(E)) to achieve the accurate measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)). However, the spectroscopy-dose rate function has been rarely measured for a CZT detector. In this study, we performed spectrum measurement using a hemispherical CZT detector in a radiation protection standards laboratory. The spectroscopy-dose rate function G(E) of the CZT detector was calculated using the least-squares method combined with the standard dose rate at the measurement position. The results showed that the hemispherical CZT detector could complete the measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)) by using the G(E) function at energies between 48 keV and 1.25 MeV, and the relative intrinsic errors were, respectively, controlled within ± 2. 3 and ± 2. 1%.
文摘Elucidation of the relationships between genetic polymorphisms and environmental exposures can provide insights into the pathways and mechanisms underlying complex traits. A new approach was used to detect G×E （gene-environment） interactions involved in human skin pigmentation variation to better understand the adaptive evolution of skin pigmentation. Specifically, we used genetic engineering, remote UVR （ultraviolet radiation） sensing and GIS （geographic information systems） to integrate the analysis of genetic and environmental factors into a coherent biological framework. Since we expected to generate large datasets for this multidimensional analysis, we used PCA （principal components analysis） as a spatial statistical analysis technique for analyzing the G×E interactions. The results suggest that skin pigmentation may be affected by mutations induced by UVR and support the hypothesis that global variation in skin pigmentation may be the result of localized adaptation to different UVR conditions via natural selection. Analyzing the relationships between heterozygous frequencies for SNP （single nucleotide polymorphism） loci and seasonal UVR levels as the environment changes will help elucidate the selective mechanisms involved in the UVR-induced evolution of skin pigmentation. Skin pigmentation fulfills the criteria for a successful evolutionary G×E interactions model.
基金EEB summer grants from the Department of Ecology and Evolutionary Biology,University of Tennessee(to M.N.B.-G.and M.A.R.-C.)the Miller Institute for Basic Research in Science(to G.M.C.).
文摘Aims While a growing number of studies have demonstrated the impor-tance of intraspecific differences within plant species on associ-ated arthropod communities,little is known regarding the relative strength of these effects compared to environmental factors.In this study,we examined whether intraspecific plant differences and nutrient fertilization interact to shape the arthropod community of a dominant coastal shrub,Baccharis pilularis(coyote bush).Methods We overlaid a fertilization treatment on a 12-year-old common garden experiment planted with erect and prostrate architectural morphs of Baccharis in california,USA.to collect the associated arthropod community,we vacuum sampled the crown of each Baccharis and identified individuals to species or morphospecies.Important Findings We found that arthropod richness and abundance were 2-to 3-fold greater on prostrate Baccharis than on erect morphs,but observed no main effects of fertilizer addition on the over-all arthropod communities.Predators responded as strongly as herbivores to plant morph,and both were unaffected by nutrient additions.Only the specialist stem galler,Gnorimoschema bac-charisella,showed an interactive response to plant morph and fertilization.Nitrogen,phosphorous and potassium addition had opposite effects on the two morphs,increasing stem gall abun-dance by 50%on prostrate morphs,but reducing galling by 20%on erect morphs.the architectural complexity of prostrate morphs could be the driving mechanism of differences in arthropod assemblages.Overall,our results demonstrate that communitylevel consequences of intraspecific differences in plants are strong,rather than being context dependent,and are generally maintained under different resource environments.the growing number of studies showing strong genotype than nutrient effects on associated arthropod communities suggests that this might be a generalized pattern.
