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Selenium in the Soil-Plant Environment: A Review
Uttam Saha,
Abioye Fayiga,
Leticia Sonon
Issue:
Volume 3, Issue 1, January 2017
Pages:
1-18
Received:
2 December 2016
Accepted:
22 December 2016
Published:
12 January 2017
Abstract: Selenium (Se) exhibits a “double-edged” behavior in animal and human nutrition. It is a micronutrient required in low concentrations by animals and humans, but toxic at high concentrations. Selenium deficiency has been associated with cancer and other health problems. Selenium requirements are commonly met through soils and plants such as wheat, rice, vegetables and maize in many countries. Selenium concentration in the soil generally ranges from 0.01-2.0 mg kg-1 but seleniferous soils usually contain more than 5 mg kg-1. Seleniferous soils have been reported in Ireland, China, India and USA. Weathering of parent rocks and atmospheric deposition of volcanic plumes are natural processes increasing Se levels in the environment. Anthropogenic sources of Se include irrigation, fertilizer use, sewage sludge and farmyard manure applications, coal combustion and crude oil processing, mining, smelting and waste incineration. Mobility of Se in the soil-plant system largely depends on its speciation and bioavailability in soil which is controlled by pH and redox potential. Plant uptake of Se varies with plant species and Se bioavailability in the soil. The uptake, translocation, transformation, metabolism, and functions of Se within the plant are further discussed in the paper. The release of Se in soils and subsequent uptake by plants has implications for meeting Se requirements in animals and humans.
Abstract: Selenium (Se) exhibits a “double-edged” behavior in animal and human nutrition. It is a micronutrient required in low concentrations by animals and humans, but toxic at high concentrations. Selenium deficiency has been associated with cancer and other health problems. Selenium requirements are commonly met through soils and plants such as wheat, ri...
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Genetic Parameters for Sorghum Varieties in Different Population Densities
Kareema Mohamad Wuhaib,
Banan Hassan Hadi,
Wajeeha Abed Hassan
Issue:
Volume 3, Issue 1, January 2017
Pages:
19-24
Received:
26 August 2016
Accepted:
1 September 2016
Published:
13 February 2017
Abstract: Experiments were carried out at Field Crop Dept., College of Agric., Univ. of Baghdad, during spring and fall seasons of 2013. The objectives were to estimate the:1- Phenotypic, genotypic and environmental variations, 2- Genotypic and phenotypic coefficient of variation and 3- broad sense heritability for seven traits days to 50% anthesis (DTA), plant height (PH), leaf area (LA), panicle length (PL), panicle weight (PW), crop growth rate (CGR), and grain yield per plant (GY). These traits and variances were recorded on three genotypes of sorghum (Sorghum bicolor L. Moench), Enqath, Rabih, and Kaffier. Results of statistical analysis showed that most traits had higher genotypic and phenotypic variances than environmental variance estimate, which indicated these traits were genotypic origin, and can be exploited in breeding programs. The genotypes exhibited varying degrees ratios of heritability for most traits. Such traits were responded positively to selection due to high broad sense heritability estimates. These data demonstrated high diversity for the traits studied of genotypes used.
Abstract: Experiments were carried out at Field Crop Dept., College of Agric., Univ. of Baghdad, during spring and fall seasons of 2013. The objectives were to estimate the:1- Phenotypic, genotypic and environmental variations, 2- Genotypic and phenotypic coefficient of variation and 3- broad sense heritability for seven traits days to 50% anthesis (DTA), pl...
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Screening of Rice (Oryza sativa L.) Genotypes for Salinity Tolerance in Ethiopia
Dawit Asnake,
Hussien Mohammed
Issue:
Volume 3, Issue 1, January 2017
Pages:
25-31
Received:
27 December 2016
Accepted:
9 January 2017
Published:
6 March 2017
Abstract: This study was carried out to investigate the effect of 4 different salinity levels (0, 4, 8 and 12 dSm-1) on yield of 13 rice genotypes along with a salt-tolerant and susceptible check genotypes to identify salt tolerant rice genotype to be used under irrigation. A factorial combination of the fifteen genotypes and four salinity levels was laid out in completely randomized design (CRD) in two replications in a mesh house. The experiments were conducted at Werer Agricultural research Center, eastern Ethiopia, from December, 2008 to May, 2009. Since all plants of all genotypes died under salinity level of 12 dSm-1, grain yield data obtained from three salinity levels are included in the analysis. Statistical Analysis of Variance (ANOVA) revealed highly significant difference among the test genotypes in all traits studied, witnessing the availability of ample genetic variability which can be used in breeding rice for tolerance to salinity. Salinity levels affected all measured traits. The Genotype x Salinity interaction was also significant for all traits except for Plant Height during Heading, Panicle Length, Number of Panicle, Number of Grains per panicle and Number of Tillers per plant, indicating the inconsistency of the performance of genotypes by many of the traits over the salinity levels and the need for selection of rice genotypes specifically adapted to a particular salinity level. In the pot experiment an increase in salinity from 0 to 4 and to 8 dSm-1 consistently reduced growth parameters, biomass, grain yield and its components, but delayed phenology. Genotypes IR66946-3R-176-1-1 (G15) and IR68144-2B-2-2-3-2 (G8) were tolerant to salinity both during early growth and later during vegetative growth, and seed setting. IR59418-7B-21-3 (G1), IR59418-7B-27-3 (G2) and IR72593-B-18-2-2-2 (G13) were found to be salt tolerant during vegetative growth and seed setting. These five genotypes can therefore be recommended for further testing under salt stress. Higher grain yield and its components under salt stress and smaller reduction of these parameters under salt stress as compared with values under normal growth condition should be used as selection criteria to develop salt tolerant rice genotypes. AMMI biplot analysis enabled clear discrimination of genotypes response against root zone salinity stress.
Abstract: This study was carried out to investigate the effect of 4 different salinity levels (0, 4, 8 and 12 dSm-1) on yield of 13 rice genotypes along with a salt-tolerant and susceptible check genotypes to identify salt tolerant rice genotype to be used under irrigation. A factorial combination of the fifteen genotypes and four salinity levels was laid ou...
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