Seed systems and diversity

2021 ◽  
pp. 271-288
Author(s):  
Niels Louwaars ◽  
Keyword(s):  
Farming System ◽  
Farm Management ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Seed Systems ◽  
Crop Genetic Diversity ◽  
Modern Breeding ◽  
On Farm ◽  
The Impact

Farmers use various seed systems to obtain seeds for their next crop. The diversity of seeds determines, together with other aspects of the farming system, the biodiversity in farmed areas. Conservation strategies for crop genetic resources distinguish ex situ, on-farm and in situ components. The on-farm management of such resources is highly influenced by the seed systems that farmers use. Next to primary and secondary centres of diversity, this chapter introduces a tertiary source of diversity, based on the creation of new diversity through modern breeding. The impact of different seed systems on the management of crop genetic diversity is also analysed.

Can farm-management practices reduce the impact of house mouse populations on crops in an irrigated farming system?

2004 ◽  
Vol 31 (6) ◽  
pp. 597 ◽  
Author(s):  
Peter R. Brown ◽  
Micah J. Davies ◽  
Grant R. Singleton ◽  
J. David Croft
Keyword(s):  
House Mouse ◽  
Management Practices ◽  
Farming System ◽  
Farm Management ◽  
Advisory Panel ◽  
Farming Practices ◽  
Management Actions ◽  
Winter Cereals ◽  
Significant Difference ◽  
The Impact

The impacts of a range of farm-management practices on house mouse (Mus domesticus) populations were tested in a large replicated field study in a complex irrigated farming system in southern New South Wales, Australia. An advisory panel, made up of farmers, extension officers, industry representatives and scientists developed a series of best-practice farm-management actions to minimise the impact of mice. Twelve experimental sites were split into six treated sites, where farmers were encouraged to conduct the recommended practices, and six untreated sites, where farmers conducted their normal farming practices. Mouse abundance was generally low to moderate for the 4-year project (5–60% adjusted trap success). We found significant reductions in population abundance of mice on treated sites when densities were moderate, but no differences when densities were low. Biomass of weeds and grasses around the perimeter of crops were significantly lower on treated sites because of applications of herbicide sprays and grazing by sheep. We could not detect any significant difference in mouse damage to crops between treated and untreated sites; however, levels of damage were low (<5%). Yields of winter cereals and rice crops were significantly higher on treated sites by up to 40%. An analysis of benefits and costs of conducting farming practices on treated sites compared with untreated sites showed a 2 : 1 benefit to cost ratio for winter cereals, 9 : 1 for rice and 4 : 1 for soybeans.

Soil seed bank and vegetation dynamics in Sahelian fallows; the impact of past cropping and current grazing treatments

2004 ◽  
Vol 20 (6) ◽  
pp. 683-691 ◽  
Author(s):  
Bruno Hérault ◽  
Pierre Hiernaux
Keyword(s):  
Seed Bank ◽  
Management Practices ◽  
Soil Seed Bank ◽  
Residual Effects ◽  
Ex Situ ◽  
Phosphorus Fertilizer ◽  
Wet Season ◽  
Seed Extraction ◽  
The Impact

The soil seed bank in a 5-y-old Sahelian fallow was studied through seed extraction and compared with germinations recorded either in controlled conditions, ex situ in a glasshouse, or in the field. The influence of phosphorus fertilizer and mulch application during the preceding crop period, and that of seasonal grazing regimes applied the last 2 y of fallowing, were assessed on the composition of the seed stock. Ctenium elegans, Fimbristylis hispidula, Merremia pinnata and Phyllanthus pentandrus accounted together for 75% of extracted seeds, 72% of ex situ, and 62% of in situ seedlings. Mulch treatment was correlated with the first axis of the canonical correspondence analyses performed on the seedling datasets. Mulch and phosphorus fertilizer treatments held similar responses, as they both favoured the seed bank of erect dicotyledons such as P. pentandrus and Cassia mimosoides. On the whole, the effects of grazing remained modest compared with the residual effects of past crop management practices. However, seedling densities increased as a result of dry-season grazing, while the soil seed bank decreased with wet-season grazing. Grazing also reduced the spatial heterogeneity of the seed bank rather than the overall number of species.

The importance of the turbulent ship wake regime for pollutant fate and transport

2021 ◽  
Author(s):  
Amanda T. Nylund ◽  
Rickard Bensow ◽  
Mattias Liefvendahl ◽  
Arash Eslamdoost ◽  
Anders Tengberg ◽  
...  
Keyword(s):  
Fate And Transport ◽  
In Situ Measurements ◽  
Ex Situ ◽  
Landsat 8 ◽  
Turbulent Regime ◽  
Near Wake ◽  
Ship Wake ◽  
Spatiotemporal Scales ◽  
The Impact

&lt;p&gt;This interdisciplinary study with implications for fate and transport of pollutants from shipping, investigates the previously overlooked phenomenon of ship induced mixing. When a ship moves through water, the hull and propeller induce a long-lasting turbulent wake. Natural waters are usually stratified, and the stratification influences both the vertical and horizontal extent of the wake. The altered turbulent regime in shipping lanes governs the distribution of discharged pollutants, e.g. PAHs, metals, nutrients and non-indigenous species. The ship related pollutant load follows the trend in volumes of maritime trade, which has almost tripled since the 1980s. In heavily trafficked areas there may be one ship passage every ten minutes; today shipping constitutes a significant source of pollution.&lt;/p&gt;&lt;p&gt;To understand the environmental impact of shipping related pollutants, it is essential to know their fate following regional scale transport. However, previous modelling efforts assuming discharge at the surface will not adequately reflect the input values in the regional models. Therefore, it is urgent to bridge the gaps between the spatiotemporal scales from high-resolution numerical modeling of the flow hydrodynamics around the ship, mixing processes and interaction of the ship and wake with stratification, and parameterization in regional oceanographic modeling. Here this knowledge gap is addressed by combining an array of methods; in situ measurements, remote sensing and numerical flow modeling.&lt;/p&gt;&lt;p&gt;A bottom-mounted Acoustic Doppler Current Profiler was placed under a ship lane, for &lt;em&gt;in-situ&lt;/em&gt; measurements of the vertical and temporal expansion of turbulent wakes. In addition, &lt;em&gt;ex-situ&lt;/em&gt; measurements with Landsat 8 Thermal Infrared Sensor were used to estimate the longevity and spatial extent of the thermal signal from ship wakes. The computational modelling was conducted using well resolved 3D RANS modelling for the hull and the near wake (up to five ship lengths aft), a method typically used for the near wake behaviour in analysing the propulsion system. As this is not feasible to use for a far wake analysis, the predicted wake is then used as input for a 2D+time modelling for the sustained wake up to 30min after the ship passage. These results, both from measurements and numerical models, are then combined to analyse how ship-induced turbulence influence at what depth discharged pollutants will be found.&lt;/p&gt;&lt;p&gt;This first step to cover the mesoscales of the turbulent ship wake is necessary to assess the impact of ship related pollution. In-situ measurements show median wake depth 13.5m (max 31.5m) and median longevity 10min (max 29min). Satellite data show median thermal wake signal 13.7km (max 62.5km). A detailed simulation model will only be possible to use for the first few 100m of the ship wake, but the coupling to a simplified 2D+time modelling shows a promising potential to bridge our understanding of the impact of the ship wake on the larger scales. Our model results indicate that the natural stratification affects the distribution and retention of pollutants in the wake region. The depth of discharge and the wake turbulence characteristics will in turn affect the fate and transport of pollutants on larger spatiotemporal scales.&lt;/p&gt;

Genetic gap analysis of wildHordeumtaxa

2012 ◽  
Vol 10 (3) ◽  
pp. 242-253 ◽  
Author(s):  
Holly Vincent ◽  
Roland von Bothmer ◽  
Helmut Knüpffer ◽  
Ahmed Amri ◽  
Jan Konopka ◽  
...  
Keyword(s):  
Gap Analysis ◽  
Plant Genetic Resources ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Gene Pools ◽  
Barley Plant ◽  
Genetic Reserve ◽  
Set Up ◽  
Global Inventory

To facilitate the updating ofin situandex situconservation strategies for wild taxa of the genusHordeumL., a combined ecogeographic survey and gap analysis was undertaken. The analysis was based on the Global Inventory of Barley Plant Genetic Resources held by ICARDA plus additional datasets, resulting in a database containing 17,131 wildHordeumaccessions. The analysis concluded that a genetic reserve should be established in the Mendoza Province of Argentina, as this is the most species-rich area globally forHordeum. A network of reserves should also be set up across the Fertile Crescent in Israel, Palestine, Syria, Jordan, Lebanon and Turkey to provide effective conservation within the centres of diversity for gene pools 1B (Hordeum vulgaresubsp.spontaneum(C. Koch) Thell.) and 2 (Hordeum bulbosumL.). The majority of the species were deemed under-collected, so further collecting missions are required worldwide where possible. Althoughex situandin situconservation strategies have been developed, there needs to be further investigation into the ecological environments thatHordeumspecies occupy to ensure that any adaptive traits expressed are fully conserved. Additionally, studies are required to characterize existing collections and test the viability of rare species accessions held in genebanks to determine whether furtherex situcollections are required alongside the proposedin situconservation.

scholarly journals Data analysis methods adopted under in situ global project in Nepal

1970 ◽  
Vol 6 ◽  
pp. 98-108
Author(s):  
Bal K Joshi ◽  
Madhusudan P Upadhyay ◽  
Hari P Bimb ◽  
D Gauchan ◽  
BK Baniya
Keyword(s):  
Data Analysis ◽  
Experimental Design ◽  
Seed Systems ◽  
Statistical Tools ◽  
Crop Species ◽  
Analysis Methods ◽  
On Farm ◽  
Global Project ◽  
Data Analysis Methods

Synthesizing data analysis methods adopted under in situ global project in Nepal along withvariables and nature of study could be guiding reference for researchers especially to those involvedin on farm research. The review work was conducted with the objective to help in utilizing andmanaging in situ database system. The objectives of the experiment, the structure of the treatmentsand the experimental design used primarily determine the type of analysis. There were 60 papers ofthis project published in Nepal. All these papers are grouped under 8 thematic groups namely 1.Agroecosystem (3 papers), 2. Agromorphological and farmers’ perception (7 papers), 3. Croppopulation structure (5 papers), 4. Gender, policy and general (15 papers), 5. Isozyme andmolecular (6 papers), 6. Seed systems and farmers’ networks (5 papers), 7. Social, cultural andeconomical (11 papers) and 8. Value addition (8 papers). All these papers were reviewed basicallyfor data type, sample size, sampling methods, statistical methods and tools, varieties and purposes.Descriptive and inferential statistics along with multivariate methods were commonly used in onfarm research. Experimental design, the most common in on station trial was least used. Study overspace and time was not adopted. There were 5 kinds of data generated, 45 statistical tools adoptedin eight different crop species. Among the 5 kinds of data under these eight subject areas,categorical type was highest followed by discrete numerical. Binary type was least in frequency.Most of the papers were related to rice followed by taro and finger millet. Cucumber and pigeonpea were studied least. Descriptive statistics along with Χ2, multivariate analysis and regressionapproaches would be appropriate tools. Similarly SPSS and MINITAB may be good software. Thebest one among a number of statistical tools should be selected and utmost care must be exercisedwhile collecting data.Key words: Data analysis methods; on farm research; on station research; subject areasDOI: 10.3126/narj.v6i0.3371Nepal Agriculture Research Journal Vol.6 2005 pp.98-108

Key issues facing genebanks in preserving crop genetic diversity ex situ: overview of the range of challenges

2021 ◽  
pp. 139-154
Author(s):  
Paula Bramel ◽  
Keyword(s):  
Genetic Diversity ◽  
Genetic Resources ◽  
Plant Genetic Resources ◽  
Cost Effective ◽  
Ex Situ ◽  
Crop Genetic Diversity ◽  
Ex Situ Collections ◽  
Key Issues ◽  
Market Preference ◽  
The Impact

This chapter reviews the key issues and challenges facing genebanks in preserving crop genetic diversity ex situ. Local crop genetic diversity is challenged with changes in land use, urbanization, land degradation, changes in agricultural practises, availability of improved varieties, changes in market preference, and the impact of climate change. Efforts have been made to secure plant genetic resources ex situ for future use but there are significant issues related to cost effective, efficient, secure, rational, and sustainable long-term ex situ conservation. It begins by addressing issues for the composition of ex situ collections and moves on to discuss issues for routine operations for conservation. The chapter also highlights issues for the use of conserved genetic resources, before concluding with a summary of why the development of sustainable genebank systems is so important.

scholarly journals Application of the MSAP Technique to Evaluate Epigenetic Changes in Plant Conservation

2020 ◽  
Vol 21 (20) ◽  
pp. 7459
Author(s):  
María Elena González-Benito ◽  
Miguel Ángel Ibáñez ◽  
Michela Pirredda ◽  
Sara Mira ◽  
Carmen Martín
Keyword(s):  
Dna Methylation ◽  
In Situ Conservation ◽  
Plant Conservation ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Regenerated Plants ◽  
Before And After ◽  
Methylation Patterns

Epigenetic variation, and particularly DNA methylation, is involved in plasticity and responses to changes in the environment. Conservation biology studies have focused on the measurement of this variation to establish demographic parameters, diversity levels and population structure to design the appropriate conservation strategies. However, in ex situ conservation approaches, the main objective is to guarantee the characteristics of the conserved material (phenotype and epi-genetic). We review the use of the Methylation Sensitive Amplified Polymorphism (MSAP) technique to detect changes in the DNA methylation patterns of plant material conserved by the main ex situ plant conservation methods: seed banks, in vitro slow growth and cryopreservation. Comparison of DNA methylation patterns before and after conservation is a useful tool to check the fidelity of the regenerated plants, and, at the same time, may be related with other genetic variations that might appear during the conservation process (i.e., somaclonal variation). Analyses of MSAP profiles can be useful in the management of ex situ plant conservation but differs in the approach used in the in situ conservation. Likewise, an easy-to-use methodology is necessary for a rapid interpretation of data, in order to be readily implemented by conservation managers.

In situ and on-farm management of plant genetic resources

2003 ◽  
Vol 19 (4) ◽  
pp. 509-517 ◽  
Author(s):  
K. Hammer ◽  
Th. Gladis ◽  
A. Diederichsen
Keyword(s):  
Genetic Resources ◽  
Plant Genetic Resources ◽  
Farm Management ◽  
On Farm

Soil copper contamination effect on carbon mineralisation: evidence of a soil CO2 emission decrease from literature review

2020 ◽  
Author(s):  
Sereni Laura ◽  
Guenet Bertrand ◽  
Crouzet Olivier ◽  
Lamy Isabelle
Keyword(s):  
Soil Respiration ◽  
Soil Carbon ◽  
Ex Situ ◽  
Soil Parameters ◽  
Copper Contamination ◽  
Carbon Mineralisation ◽  
Cu Contamination ◽  
C Mineralisation ◽  
The Impact

&lt;p&gt;Among all pollutants, copper (Cu) is of major environmental and toxicological concern with contamination from various origins. Moreover as a cation, Cu is easily complexed by the negatively charged soil organic matter (OM) inducing high concentrations in upper layers of soils where OM dominates. Due to its biotic and abiotic interactions with soil constituents Cu is expected to affect several soil processes among them the soil respiration, but studies provided contrasting results as soil respiration have been shown to decrease or increase with soil contamination depending on the studies.&lt;/p&gt;&lt;p&gt;In this study, we aimed at assessing how soil respiration is affected by Cu contamination in order to quantifying as a first approach the GHG emissions for a contaminated soil. We performed a quantitative review of literature focusing on soil heterotrophic respiration (thus excluding autotrophic respiration from plants) which aimed at 1) assessing the impact of a copper contamination on soil carbon (C) mineralisation and thus CO&lt;sub&gt;2&lt;/sub&gt; emissions, and 2) hierarchizing the determinants of such an impact on C mineralisation compare to the influence of pedo-climatic soil parameters such as pH, clay percentage or the type of climate.&lt;/p&gt;&lt;p&gt;On the basis of a selection of roughly 390 literature data, global main results showed a decrease in soil CO&lt;sub&gt;2&lt;/sub&gt; emission with an increase in soil Cu contamination. Data from ex situ spiking experiments could be easily differentiated from the ones originated from in situ natural contamination due to their sharper decrease in soil organic carbon mineralisation. Interestingly, ex situ spikes data on the short term provided a threshold: an increase in soil CO&lt;sub&gt;2&lt;/sub&gt; emissions was noticed for data below total soil Cu content of 180 mg kg&lt;sup&gt;-1&lt;/sup&gt; while a decrease was observed above this concentration. On the contrary, long-term in situ contamination due to anthropogenic activities (urbanisation, agriculture &amp;#8230;) did not significantly impact soil carbon mineralisation except when we focused on the high inputs of industrial contamination (smelter, composted plant&amp;#8230;). Soil pH was found as a variable of interest as acidic soils were more sensitive to Cu contamination for C mineralisation than neutral or alkaline soils, while the % of clay and the type of climate did not add explanation to the variation in C mineralisation. These results are discussed and the collected data allowed us to propose a general equation quantifying how soil respiration can be affected by a Cu contamination.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document