Genotype x environment interaction in European black alder (Alnus glutinosa (L.) Gaertn)

A subset of 17 provenances from an on-going range-wide provenance study of European black alder (Alnus glutinosa) was evaluated in three locations (Iowa, Illinois and Wisconsin) for growth (total height, height growth rates, diameter and volume) and raw biomass properties (field moisture content, maximum moisture content, specific gravity and stem biomass) as well as leaf tissue nitrogen and flower production;Significant differences were found among provenances for all the traits except bark and field moisture contents. The Iowa location had significantly higher mean performances than either southern Illinois or northern Wisconsin locations. Combined analysis over years and locations showed no significant provenance x environment interaction for the raw biomass properties except for maximum moisture content. Growth properties such as height and diameter were positively correlated with each other. Very low correlations were obtained between growth and biomass properties. Leaf tissue nitrogen, bark content and field moisture content had negative correlations with many of the other variables;Estimates of broad sense heritabilities ranged from 0.03 to 0.93 for the different traits within locations and across locations and years. The moderate levels of heritability estimates yield fairly high predicted genetic gains, indicating that genetic improvements are possible for Alnus glutinosa when grown in North Central United States;Stability analysis revealed that the southern European provenances had above average stability while the northern seed sources had below average stability for total height measurements. The German and Danish sources, and two Yugoslavian sources showed average stability over all locations. Cluster analysis grouped Iowa and Illinois into one breeding zone and northern Wisconsin into another, while location: location genotypic correlations indicated that Wisconsin and Illinois could not be in the same breeding zone. However, two concurrent breeding programs are possible for Iowa location, whereby selections could be made for production in Wisconsin and southern Illinois

Management and Recycling of Secondhand Electronic Devices Case of Nigeria

AbstractApproximately 60,000 tons of e-waste from new, secondhand, or used electrical electronics equipment/devices (UEEEDs) are disposed off at the end of their shelf life annually in Lagos, Nigeria. The purpose of this qualitative case study was to understand better how secondhand or UEEED e-waste was efficiently managed or recycled without resulting in environmental concerns. The study’s conceptual framework was based on Machiavellian and transactional conceptual theories. The research question focused on what influences the choice of management and recycling of electronic devices. Data were collected from 28 participants through semistructured interviews with 8 business owners and 20 focus group UEEED users. Data analysis was through thematic content analysis, and ethnography. The prevailing themes findings of the study showed that 10,000 tons of e-waste from pocket PCs, laptops, computers, and household electrical appliances, were generated weekly, amounting to 120,000 tons yearly in Lagos from Alaba International Market and Ikeja Computer Village. This number had tripled yearly compared to previous studies in Nigeria in the past 5 years due to a lack of national e-waste policy and stringent enforcement, management, and product quality monitoring by regulatory bodies in Nigeria. The result indicated that a gap in e-waste generation, management, and recycling had social and economic implications for the unabating e-waste generation from UEEED, as the United Nations pointed out. The social implications for positive change are the precursors for efficient management and recycling of e-waste from UEEED and to assuage global and local concerns highlighted by WHO in preventing the possible longterm and negative biological consequences on the ecosystem and humanity

Competing Risk of Death and Time-Varying Covariates in Cardiovascular Epidemiologic Research: Modeling the Hazards of Coronary Heart Disease in the First National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study

Competing risk of death and time-varying covariates, often overlooked during statistical analyses of longitudinal studies, can alter the magnitude of estimates of the effect of covariates on the hazards of health outcomes. This study aimed to investigate whether estimates obtained when modeling the effect of risk factors on the hazards of coronary heart disease (CHD) varied significantly while accounting for the presence of competing risk of death and time-varying covariates. We used data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study (n=6346) to model estimates of the effect of risk factors on the hazards of CHD using Cox proportional hazards model, Cox extension with time-varying covariates, and the Fine Gray approach. We used a chi-square test to compare coefficient estimates obtained from the three modeling techniques. We obtained a P-value > 0.05 when comparing coefficient estimates for body mass index, age, cholesterol, smoking, and diabetes after fitting the three models. Coefficient estimates obtained when modeling the effect of risk factors on the hazards of CHD did not vary significantly in the presence of competing risk of death and time-varying covariates. Researchers should consider exploring these concepts more systematically in cohort studies with cardiovascular outcomes

Phytotherapy and Polycyclic Logging: Implication on Genetic Multiplicity and Diversity of African Mahogany in Tropical Rainforest

There are over 8,000 globally threatened tree species. For each species, there is a different story behind why they are threatened and what values we stand to lose if we do not find the means to save them. Mahogany, a member of Meliaceae, is a small genus with six species. Its straight, fine and even grain, consistency in density and hardness makes it a high valued wood for construction purposes. The bitter bark is widely used in traditional medicine in Africa. The high demand for bark has also led to the total stripping of some trees, complete felling of larger trees to get the bark from the entire length of the tree and bark removal from juvenile trees. These species are now threatened with extinction due to selective and polycyclic logging, and also excessive bark removal. The natural regeneration of mahogany is poor, and mahogany shoot borer Hypsipyla robusta (Moore) attacks prevent the success of plantations within the native area in West Africa. In developing countries, most of the Khaya species exists in the wild state; therefore, the regeneration and long-term conservation are at the mercy of the vagaries of nature and the profit driven herb collectors and timber merchants. It becomes urgently necessary by government of developing countries to place ban on further harvesting of mahogany species to allow the remaining few trees of mahogany in the forest to recuperate and produce substantial seeds for regeneration

Resistance to Elsinoë Ampelina and Expression of Related Resistant Genes in Vitis Rotundifolia Michx. Grapes

Muscadine grapes (Vitis rotundifolia Michx) are considered as excellent genetic resources for grape breeding programs as they are known for their hardiness and resistance to pests and diseases. However, contrary to popular belief, our study indicated that not all muscadine cultivars are resistant to anthracnose disease. In order to identify a source of genetic tolerance towards anthracnose among muscadine cultivars, a series of in-situ and ex-situ experiments were conducted through strict and sensitive screening processes. Two consecutive years of field evaluation of 54 grape cultivars showed various levels of anthracnose incidence among the cultivars between a scale of 0 (tolerant) to 5 (highly-susceptible). Resistance bioassay by inoculation of different spore densities of Elsinoë ampelina on 40 cultivars presented similar results and was consistent with those obtained from the field test. A real-time PCR analysis was conducted to investigate differences of gene expression between susceptible and tolerant cultivars and to confirm results by phenotypic identification. Expression of genes encoding chalcone synthase, stilbene synthase, polygalacturonase-inhibiting protein, chitinase and lipid transfer-protein was only detected in tolerant cultivars. Resistant muscadine cultivars identified in this study could be excellent candidates for grape disease resistance breeding programs

Genetic divergence of rubber tree estimated by multivariate techniques and microsatellite markers

Genetic diversity of 60 Hevea genotypes, consisting of Asiatic, Amazonian, African and IAC clones, and pertaining to the genetic breeding program of the Agronomic Institute (IAC), Brazil, was estimated. Analyses were based on phenotypic multivariate parameters and microsatellites. Five agronomic descriptors were employed in multivariate procedures, such as Standard Euclidian Distance, Tocher clustering and principal component analysis. Genetic variability among the genotypes was estimated with 68 selected polymorphic SSRs, by way of Modified Rogers Genetic Distance and UPGMA clustering. Structure software in a Bayesian approach was used in discriminating among groups. Genetic diversity was estimated through Nei's statistics. The genotypes were clustered into 12 groups according to the Tocher method, while the molecular analysis identified six groups. In the phenotypic and microsatellite analyses, the Amazonian and IAC genotypes were distributed in several groups, whereas the Asiatic were in only a few. Observed heterozygosity ranged from 0.05 to 0.96. Both high total diversity (HT' = 0.58) and high gene differentiation (G st' = 0.61) were observed, and indicated high genetic variation among the 60 genotypes, which may be useful for breeding programs. The analyzed agronomic parameters and SSRs markers were effective in assessing genetic diversity among Hevea genotypes, besides proving to be useful for characterizing genetic variability

Genotype x environment interaction in European black alder (Alnus glutinosa (L.) Gaertn)

A subset of 17 provenances from an on-going range-wide provenance study of European black alder (Alnus glutinosa) was evaluated in three locations (Iowa, Illinois and Wisconsin) for growth (total height, height growth rates, diameter and volume) and raw biomass properties (field moisture content, maximum moisture content, specific gravity and stem biomass) as well as leaf tissue nitrogen and flower production;Significant differences were found among provenances for all the traits except bark and field moisture contents. The Iowa location had significantly higher mean performances than either southern Illinois or northern Wisconsin locations. Combined analysis over years and locations showed no significant provenance x environment interaction for the raw biomass properties except for maximum moisture content. Growth properties such as height and diameter were positively correlated with each other. Very low correlations were obtained between growth and biomass properties. Leaf tissue nitrogen, bark content and field moisture content had negative correlations with many of the other variables;Estimates of broad sense heritabilities ranged from 0.03 to 0.93 for the different traits within locations and across locations and years. The moderate levels of heritability estimates yield fairly high predicted genetic gains, indicating that genetic improvements are possible for Alnus glutinosa when grown in North Central United States;Stability analysis revealed that the southern European provenances had above average stability while the northern seed sources had below average stability for total height measurements. The German and Danish sources, and two Yugoslavian sources showed average stability over all locations. Cluster analysis grouped Iowa and Illinois into one breeding zone and northern Wisconsin into another, while location: location genotypic correlations indicated that Wisconsin and Illinois could not be in the same breeding zone. However, two concurrent breeding programs are possible for Iowa location, whereby selections could be made for production in Wisconsin and southern Illinois.</p