scholarly journals Gene flow in commercial alfalfa (Medicago sativa subsp. sativa L.) seed production fields: Distance is the primary but not the sole influence on adventitious presence

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248746
Author(s):  
Sandya R. Kesoju ◽  
Matthew Kramer ◽  
Johanne Brunet ◽  
Stephanie L. Greene ◽  
Amelia Jordan ◽  
...  
Keyword(s):  
Gene Flow ◽  
Management Practices ◽  
Genetically Engineered ◽  
Foraging Range ◽  
Alfalfa Seed ◽  
Level Model ◽  
Adventitious Presence ◽  
Isolation Distances ◽  
System Life ◽  
The Impact

In insect-pollinated crops, gene flow is affected by numerous factors including crop characteristics, mating system, life history, pollinators, and planting management practices. Previous studies have concentrated on the impact of distance between genetically engineered (GE) and conventional fields on adventitious presence (AP) which represents the unwanted presence of a GE gene. Variables other than distance, however, may affect AP. In addition, some AP is often present in the parent seed lots used to establish conventional fields. To identify variables that influence the proportion of AP in conventional alfalfa fields, we performed variable selection regression analyses. Analyses based on a sample-level and a field-level analysis gave similar, though not identical results. For the sample-level model, distance from the GE field explained 66% of the variance in AP, confirming its importance in affecting AP. The area of GE fields within the pollinator foraging range explained an additional 30% of the variation in AP in the model. The density of alfalfa leafcutting bee domiciles influenced AP in both models. To minimize AP in conventional alfalfa seed fields, management practices should focus on optimizing isolation distances while also considering the size of the GE pollen pool within the pollinator foraging range, and the foraging behavior of pollinators.

scholarly journals Effect of fire and thinning on fine-scale genetic structure and gene flow in fire-suppressed populations of sugar pine (Pinus lambertiana Douglas)

2018 ◽  
Author(s):  
Brandon M. Lind ◽  
Malcolm P. North ◽  
Patricia E. Maloney ◽  
Andrew J. Eckert
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Sierra Nevada ◽  
Prescribed Fire ◽  
Management Practices ◽  
Fine Scale ◽  
Pinus Lambertiana ◽  
Sugar Pine ◽  
The Impact ◽  
Pine Species

AbstractHistorically, frequent, low-severity fires in dry western North American forests were a major driver of ecological patterns and processes, creating resilient ecosystems dominated by widely-spaced pine species. However, a century of fire-suppression has caused overcrowding, altering forest composition to shade-tolerant species, while increasing competition and leaving trees stressed and susceptible to pathogens, insects, and high-severity fire. Exacerbating the issue, fire incidence is expected to increase with changing climate, while fire season has been observed to begin earlier and last longer than historic trends. Forest thinning and prescribed fire have been identified as important management tools to mitigate these risks. Yet little is known of how thinning, fire, or their interaction affect contemporary evolutionary processes of constituent pine species that influence fitness and play an important role in the opportunity for selection and population persistence. We assessed the impact of widely used fuel reduction treatments and prescribed fire on fine-scale gene flow on an ecologically important and historically dominant shade-intolerant pine species of the Sierra Nevada, Pinus lambertiana Dougl. Treatment prescription (no-thin-no-fire, thin-no-fire, and fire-and-thin) was found to differentially affect both fine-scale spatial and genetic structure as well as effective gene flow in this species. Specifically, the thin-no-fire prescription increases genetic structure (spatial autocorrelation of relatives) between adults and seedlings, while seed and pollen dispersal increase and decrease, respectively, as a function of increasing disturbance intensity. While these results may be specific to the stands at our study site, they indicate how assumptions relating to genetic effects based on spatial structure can be misleading. It is likely that these disequilibrated systems will continue to evolve on unknown evolutionary trajectories. The long-term impacts of management practices on reduced fitness from inbreeding depression should be continually monitored to ensure resilience to increasingly frequent and severe fire, drought, and pest stresses.

Growth, Fitness, and Overwinter Survival of a Shattercane (Sorghum bicolorssp.drummondii)×Grain Sorghum (Sorghum bicolorssp.bicolor) F2Population

Weed Science ◽  
2018 ◽  
Vol 66 (5) ◽  
pp. 634-641
Author(s):  
Jared J. Schmidt ◽  
Melinda K. Yerka ◽  
Jeffrey F. Pedersen ◽  
John L. Lindquist
Keyword(s):  
Gene Flow ◽  
Sorghum Bicolor ◽  
Population Biology ◽  
Insect Pests ◽  
Cropping System ◽  
Grain Sorghum ◽  
Genetically Engineered ◽  
Overwinter Survival ◽  
Ecological Fitness ◽  
The Impact

AbstractAlthough sorghum [Sorghum bicolor(L.) Moench ssp.bicolor] is the fifth most important grain crop in terms of global production, no commercial hybrids carry genetically engineered (GE) traits for resistance to insect pests or herbicides due to regulatory concerns about gene flow to weedy relatives. However, non-GE herbicide resistance currently is being developed in grain sorghum and will likely transfer to related weeds. Monitoring the impact of this new nuclear technology on the evolution and invasiveness of related weeds requires a baseline understanding of the population biology of grain sorghum genes once they transfer to in situ weed populations. We previously characterized the rate of gene flow from grain sorghum to shattercane [Sorghum bicolor(L.) Moench nothosubsp.drummondii(Steud.) de Wet ex. Davidse], a conspecific weed relatively common in North America; as well as the ecological fitness of an F1population whenS. bicolornothosubsp.drummondiiwas the maternal parent. Here we report the ecological fitness of aS. bicolornothosubsp.drummondii×S. bicolorssp.bicolorF2population relative to its crop and weed parents. Parental and F2populations were grown in two Nebraska environments in 2012 and 2013. Traits evaluated included overwinter survival, field emergence, biomass production and partitioning at anthesis, total seed production, and 100-seed weight. Results indicated that F2traits were generally intermediate between the parents, but more similar toS. bicolornothosubsp.drummondiithan to grain sorghum. The one exception was overwinter survival, which was nearly 0% for both the F2and the grain sorghum parent in these northern environments. Thus, the frequency of crop alleles stably introgressed intoS. bicolornothosubsp.drummondiipopulations appears to primarily depend on overwinter survival of the F2and which selective pressures are imposed upon it by the cropping system. These data provide needed baseline information about the environmental fate of nuclear genetic technologies deployed in this important global crop.

The Impact of Shariah Governance and Corporate Governance on the Risk Management Practices: Evidence from Local and Foreign Islamic Banks in Malaysia

2018 ◽  
Vol 15 (2) ◽  
pp. 1-20
Author(s):  
Sabri Embi ◽  
Zurina Shafii
Keyword(s):  
Risk Management ◽  
Corporate Governance ◽  
Management Practices ◽  
Principal Component ◽  
T Test ◽  
The Body ◽  
Primary Data ◽  
Islamic Banks ◽  
Shariah Governance ◽  
The Impact

The purpose of this study is to examine the impact of Shariah governance and corporate governance (CG) on the risk management practices (RMPs) of local Islamic banks and foreign Islamic banks operating in Malaysia. The Shariah governance comprises the Shariah review (SR) and Shariah audit (SA) variables. The study also evaluates the level of RMPs, CG, SR, and SA between these two type of banks. With the aid of SPSS version 20, the items for RMPs, CG, SR, and SA were subjected to principal component analysis (PCA). From the PCA, one component or factor was extracted each for the CG, SR, and RMPs while another two factors were extracted for the SA. Primary data was collected using a self-administered survey questionnaire. The questionnaire covers four aspects ; CG, SR, SA, and RMPs. The data received from the 300 usable questionnaires were subjected to correlation and regression analyses as well as an independent t-test. The result of correlation analysis shows that all the four variables have large positive correlations with each other indicating a strong and significant relationship between them. From the regression analysis undertaken, CG, SR, and SA together explained 52.3 percent of the RMPs and CG emerged as the most influential variable that impacts the RMPs. The independent t-test carried out shows that there were significant differences in the CG and SA between the local and foreign Islamic banks. However, there were no significant differences between the two types of the bank in relation to SR and RMPs. The study has contributed to the body of knowledge and is beneficial to academicians, industry players, regulators, and other stakeholders.

INFLUENCE OF GREENHOUSE SHADING AND DIFFERENT NUTRIENT MANAGEMENT PRACTICES ON ALLEVIATING HEAT STRESS, IMPROVING PLANT NUTRIENTS STATUS, FLOWERING GROWTH AND YIELD OF TOMATO

2020 ◽  
Vol 51 (4) ◽  
pp. 1001-1014
Author(s):  
Sulaiman & Sadiq
Keyword(s):  
Heat Stress ◽  
Management Practices ◽  
Nutrient Management ◽  
Block Design ◽  
Nutrient Status ◽  
Growth And Yield ◽  
Reproductive Growth ◽  
Positive Effects ◽  
Nutrition Programs ◽  
The Impact

The experiment was conducted in a greenhouse during 2017 and 2018 growing seasons to evaluate the impact of the shading and various nutrition programs on mitigating heat stress, reducing the use of chemical minerals, improving the reproductive growth and yield of tomato plant. Split-plot within Randomized Complete Block Design (RCBD) with three replications was conducted in this study. Shading factor was allocated in the main plots and the nutrition programs distributed randomly in the subplots. Results indicate that shading resulted in the decrease of daytime temperature by 5.7˚C as an average for both seasons; thus a significant increasing was found in leaf contents of macro nutrients (Nitrogen, Phosphorous, and Potassium), and micro nutrients (Iron, Zinc and Boron), except the Iron content in 2018 growing season. Furthermore, shading improved significantly the reproductive growth and tomato yield. Among the plant nutrition programs, the integrated nutrient management (INM) including the application of organic substances, bio inoculum of AMF and 50% of the recommended dose of chemical fertilizers; lead to the enhancement of nutrients content, reproductive characteristics and plant yield. Generally, combination of both shading and INM showed positive effects on plants nutrient status and persisting balance on tomato flowering growth and fruits yield.

Estimating the Impact of Alkali Bees on the Yield and Acreage of Alfalfa Seed

jpa ◽  
1992 ◽  
Vol 5 (4) ◽  
pp. 512-518 ◽  
Author(s):  
Dennis Wichelns ◽  
Thomas F. Weaver ◽  
Priscilla M. Brooks
Keyword(s):  
Alfalfa Seed ◽  
The Impact

scholarly journals Analyzing Factors Affecting the Sustainability of Land Management Practices in Mecha Woreda, Northwestern Ethiopia

2021 ◽  
Vol 13 (13) ◽  
pp. 7007
Author(s):  
Habtamu Nebere ◽  
Degefa Tolossa ◽  
Amare Bantider
Keyword(s):  
Decision Making ◽  
Land Management ◽  
Land Degradation ◽  
Quantitative Data ◽  
Management Practices ◽  
Short Term ◽  
Factors Affecting ◽  
Decision Making Processes ◽  
Household Heads ◽  
The Impact

In Ethiopia, the practice of land management started three decades ago in order to address the problem of land degradation and to further boost agricultural production. However, the impact of land management practices in curbing land degradation problems and improving the productivity of the agricultural sector is insignificant. Various empirical works have previously identified the determinants of the adoption rate of land management practices. However, the sustainability of land management practices after adoption, and the various factors that control the sustainability of implemented land management practices, are not well addressed. This study analyzed the factors affecting the sustainability of land management practices after implementation in Mecha Woreda, northwestern Ethiopia. The study used 378 sample respondents, selected by a systematic random sampling technique. Binary logistic regression was used to analyze the quantitative data, while the qualitative data were qualitatively and concurrently analyzed with the quantitative data. The sustained supply of fodder from the implemented land management practices, as well as improved cattle breed, increases the sustainability of the implemented land management practices. While lack of agreement in the community, lack of enforcing community bylaws, open cattle grazing, lack of benefits of implemented land management practices, acting as barrier for farming practices, poor participation of household heads during planning and decision-making processes, as well as the lack of short-term benefits, reduce the sustainability of the implemented land management practices. Thus, it is better to allow for the full participation of household heads in planning and decision-making processes to bring practical and visible results in land management practices. In addition, recognizing short-term benefits to compensate the land lost in constructing land management structures must be the strategy in land management practices. Finally, reducing the number of cattle and practicing stall feeding is helpful both for the sustainability of land management practices and the productivity of cattle. In line with this, fast-growing fodder grass species have to be introduced for household heads to grow on land management structures and communal grazing fields for stall feeding.

scholarly journals Earthworm Abundance Changes Depending on Soil Management Practices in Slovenian Vineyards

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1241
Author(s):  
Stanko Vršič ◽  
Marko Breznik ◽  
Borut Pulko ◽  
Jesús Rodrigo-Comino
Keyword(s):  
Management Practices ◽  
Human Impacts ◽  
Soil Layer ◽  
Soil Management ◽  
Weather Conditions ◽  
Soil Tillage ◽  
Soil Biodiversity ◽  
Straw Mulch ◽  
Green Cover ◽  
The Impact

Earthworms are key indicators of soil quality and health in vineyards, but research that considers different soil management systems, especially in Slovenian viticultural areas is scarce. In this investigation, the impact of different soil management practices such as permanent green cover, the use of herbicides in row and inter-row areas, use of straw mulch, and shallow soil tillage compared to meadow control for earthworm abundance, were assessed. The biomass and abundance of earthworms (m2) and distribution in various soil layers were quantified for three years. Monitoring and a survey covering 22 May 2014 to 5 October 2016 in seven different sampling dates, along with a soil profile at the depth from 0 to 60 cm, were carried out. Our results showed that the lowest mean abundance and biomass of earthworms in all sampling periods were registered along the herbicide strip (within the rows). The highest abundance was found in the straw mulch and permanent green cover treatments (higher than in the control). On the plots where the herbicide was applied to the complete inter-row area, the abundance of the earthworm community decreased from the beginning to the end of the monitoring period. In contrast, shallow tillage showed a similar trend of declining earthworm abundance, which could indicate a deterioration of soil biodiversity conditions. We concluded that different soil management practices greatly affect the soil’s environmental conditions (temperature and humidity), especially in the upper soil layer (up to 15 cm deep), which affects the abundance of the earthworm community. Our results demonstrated that these practices need to be adapted to the climate and weather conditions, and also to human impacts.

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