Genetic characterization of cassava (Manihot esculenta) landraces in Brazil assessed with simple sequence repeats

Based on nine microsatellite loci, the aim of this study was to appraise the genetic diversity of 42 cassava (Manihot esculenta) landraces from selected regions in Brazil, and examine how this variety is distributed according to origin in several municipalities in the states of Minas Gerais, São Paulo, Mato Grosso do Sul, Amazonas and Mato Grosso. High diversity values were found among the five above-mentioned regions, with 3.3 alleles per locus on an average, a high percentage of polymorphic loci varying from 88.8% to 100%, an average of 0.265 for observed heterozygosity and 0.570 for gene diversity. Most genetic diversity was concentrated within the regions themselves (HS = 0.52). Cluster analysis and principal component based scatter plotting showed greater similarity among landraces from São Paulo, Mato Grosso do Sul and Amazonas, whereas those from Minas Gerais were clustered into a sub-group within this group. The plants from Mato Grosso, mostly collected in the municipality of General Carneiro, provided the highest differentiation. The migration of human populations is one among the possible reasons for this closer resemblance or greater disparity among plants from the various regions

Mycorrhizal-associated nutrient dynamics in key ecosystems and their response to a changing environment

CITATION: Heng, G. et al. 2016. Mycorrhizal-associated nutrient dynamics in key ecosystems and their response to a changing environment. Mycoshpere, 7(2):190–203, doi:10.5943/mycosphere/7/2/8.The original publication is available at http://www.mycosphere.orgEnvironmental change incorporates the full range of natural and anthropogenic changes currently affecting the planet. These changes include fluxes within the carbon and nutrient cycles, resulting in disturbances at the ecosystem level, which may affect plant species distribution as well as soil systems. Mycorrhizal fungi form an important link between plants and soil systems, functioning at the root-soil interface, contributing towards nutrient cycling processes, and, ultimately, influencing the plant composition of terrestrial ecosystems. A more integrated and systemic understanding of these mycorrhizal associations can help us predict, and thus mitigate, the impact of environmental change on biotic communities. In this review we present the latest research on how the carbon, nitrogen and phosphorus dynamics of arbuscular and ectomycorrhiza vary in their representative ecosystems. Furthermore, we also demonstrate how they respond to environmental change, which relates to both biotic and abiotic factors, such as CO2-enrichment, nitrogen-depletion, and the impact of invasive species. This review provides insight on the role of mycorrhiza in offsetting the negative effects of environmental change.http://www.mycosphere.org/volume-7/issue-2.htmlPublisher's versio

Création d'un manuel pédagogique comme action collaborative de promotion de l'écosanté en Asie du Sud-Est

This paper describes the development of an Ecohealth Trainer Manual that was published in May 2013 and adapted to a Southeast Asian audience. This manual was part of a project entitled the Field Building Leadership Initiative (FBLI), launched in October 2011, which aims to build the capacity of researchers, young professionals and students in Ecohealth. The FBLI is coordinated by eight institutions in Southeast Asia and aims to tackle issues related to agricultural intensification and health. As an integral step to the development of the Trainer Manual, the FBLI invited the target audience of the manual to collaborate and network, and thereby contribute directly to the production of the teaching tools they would then be expected to use to teach Ecohealth in their respective institutions. The article describes the processes and techniques used to encourage such collaboration in the multi-institutional regional context of Southeast Asia. It suggests that three conditions are necessary to allow for the emergence of co-creation during such collaborative processes : creating an enabling environment, promoting trust and respect amongst stakeholders and participants, and sharing a common goal or common purpose

Fertilizer use patterns in Yunnan Province, China: implications for agricultural and environmental policy

Balancing the need to increase crop yields with the need to reduce the environmental impacts of fertilizers will pose major policy, regulatory, and extension challenges for China. A growing number of studies have demonstrated the potential for improving fertilizer use efficiency in China, but it is not clear how to achieve these efficiency improvements on a larger scale. The empirical foundation for fertilizer policy in China is still weak, particularly in inland provinces. This paper examines fertilizer use patterns in Yunnan Province, an inland and ecologically important province in Southwest China, drawing on two household surveys. We find that fertilizer application rates in the survey areas are highly heterogeneous, among crops, households, and regions. Managing this diversity poses the largest challenge to fertilizer policy in Yunnan and, by extension, in China. None of the factors that we examine in this study are robust predictors of fertilizer intensity (kg ha−1) in the survey regions, though in one survey there is a strong inverse relationship between farm size and fertilizer intensity. The lack of clearer signals in the survey data, a consequence of heterogeneity in cropping patterns, agroecosystems, and local economies, underscores the importance of locally tailored approaches to fertilizer regulation in China, and of a strong, service-oriented agricultural extension system oriented around sustainable agriculture

Coping with climate-induced water stresses through time and space in the mountains of Southwest China

Southwest China s Yunnan province has been affected throughout history by climate-induced water stresses, with the 2009 drought as a recent example. To deal with such stresses, mountain farmers have developed many local coping strategies. This paper provides case studies of these coping mechanisms in three mountain communities in Baoshan Municipality, Yunnan province. To minimize water-related environmental and economic vulnerabilities, our results show that upland farmers employ strategies both individually and collectively, which vary according to agroecological zone, economics, and historical period. Climate change is also emerging as an ongoing environmental challenge. We explore China s options for introducing and implementing adaptation policies that link with farmer strategies to respond more effectively to water stresses induced by climate change and other forces

Separation of the bioclimatic spaces of Himalayan tree rhododendron species predicted by ensemble suitability models

The tree rhododendrons include the most widely distributed Himalayan Rhododendron species belonging to the subsection Arborea. Distributions of two members of this sub-species were modelled using bioclimatic data for current conditions (1950–2000). A subset of the least correlated bioclimatic variables was used for ecological niche modelling (ENM). We used an ENM ensemble method in the BiodiversityR R-package to map the suitable climatic space for tree rhododendrons based on 217 point location records. Ensemble bioclimatic models for tree rhododendrons had high predictive power with bioclimatic variables, which also separated the climatic spaces for the two species. Tree rhododendrons were found occurring in a wide range of climate and the distributional limits were associated with isothermality, temperature ranges, temperature of the wettest quarter, and precipitation of the warmest quarter of the year. The most suitable climatic space for tree rhododendrons was predicted to be in western Yunnan, China, with suitability declining towards the west and east. Its occurrence in a wide range of climatic settings with highly dissected habitats speaks to the adaptive capacity of the species, which might open up future options for their conservation planning in regions where they are listed as threatened