Characterization of the Rust Fungus, Puccinia emaculata, and Evaluation of Genetic Variability for Rust Resistance in Switchgrass Populations

Several fungal pathogens have been identified on ornamental and native stands of switchgrass (Panicum virgatum L.). Diseases of switchgrass, particularly rust, have been largely neglected and are likely to become the major limiting factor to biomass yield and quality, especially when monocultured over a large acreage. Based on teliospore morphology and internal transcribed spacer-based diagnostic primers, the rust pathogen collected from switchgrass research fields in Oklahoma was identified as Puccinia emaculata. Furthermore, to identify genetically diverse source(s) of rust resistance, several switchgrass genotypes from both upland (cv. ‘Summer’ and ‘Cave-in-Rock’) and lowland (cv. ‘Alamo’ and ‘Kanlow’) ecotypes were evaluated in Ardmore, Oklahoma during 2008 and 2009 and in growth chamber assays. Field and growth chamber evaluations revealed a high degree of genetic variation within and among switchgrass cultivars. In general, Alamo and Kanlow showed moderate resistance to P. emaculata, while Summer was highly susceptible. Distinct ecotypic variations for reactions to rust were also prevalent with the lowlands maintaining a high level of resistance. These results suggest the potential for improvement of rust resistance via the selection of resistant individuals from currently available cultivars. Further, the selection pressure on the pathogen would also be reduced by employing several rust resistant cultivars in production-scale situations.     

Robust modeling of additive and nonadditive variation with intuitive inclusion of expert knowledge

We propose a novel Bayesian approach that robustifies genomic modeling by leveraging expert knowledge (EK) through prior distributions. The central component is the hierarchical decomposition of phenotypic variation into additive and nonadditive genetic variation, which leads to an intuitive model parameterization that can be visualized as a tree. The edges of the tree represent ratios of variances, for example broad-sense heritability, which are quantities for which EK is natural to exist. Penalized complexity priors are defined for all edges of the tree in a bottom-up procedure that respects the model structure and incorporates EK through all levels. We investigate models with different sources of variation and compare the performance of different priors implementing varying amounts of EK in the context of plant breeding. A simulation study shows that the proposed priors implementing EK improve the robustness of genomic modeling and the selection of the genetically best individuals in a breeding program. We observe this improvement in both variety selection on genetic values and parent selection on additive values; the variety selection benefited the most. In a real case study, EK increases phenotype prediction accuracy for cases in which the standard maximum likelihood approach did not find optimal estimates for the variance components. Finally, we discuss the importance of EK priors for genomic modeling and breeding, and point to future research areas of easy-to-use and parsimonious priors in genomic modeling.     

The Road to Gold: Training and Peaking Characteristics in the Year Prior to a Gold Medal Endurance Performance

Purpose

To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature.

Methods

Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL. min⁻¹. kg⁻¹ , 7 female, 25±4 yr, 73±3 mL. min⁻¹. kg⁻¹ ) reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activity forms.

Results

Athletes trained ∼800 h/500 sessions.year⁻¹, including ∼500 h. year⁻¹ of sport-specific training. Ninety-four percent of all training was executed as aerobic endurance training. Of this, ∼90% was low intensity training (LIT, below the first lactate threshold) and 10% high intensity training (HIT, above the first lactate threshold) by time. Categorically, 23% of training sessions were characterized as HIT with primary portions executed at or above the first lactate turn point. Training volume and specificity distribution conformed to a traditional periodization model, but absolute volume of HIT remained stable across phases. However, HIT training patterns tended to become more polarized in the competition phase. Training volume, frequency and intensity remained unchanged from pre-peaking to peaking period, but there was a 32±15% (P<.01) volume reduction from the preparation period to peaking phase.

Conclusions

The annual training data for these Olympic and World champion XC skiers and biathletes conforms to previously reported training patterns of elite endurance athletes. During the competition phase, training became more sport-specific, with 92% performed as XC skiing. However, they did not follow suggested tapering practice derived from short-term experimental studies. Only three out of 11 athletes took a rest day during the final 5 days prior to their most successful competition.     

Conservation strategies for coastal wetlands in the Gulf of California,Mexico

Wetlands worldwide, the fisheries they support, and the communities that depend on them are threatened by habitat modification. We describe strategies being used for wetland conservation in the Gulf of California, Mexico, their effectiveness, and challenges for implementation. We base our analysis on the authors’ experience working for local environmental non-governmental organizations and available literature. The strategies discussed include public and private policy instruments such as Environmental Impact Evaluations, environmental land easements, concessions and transfer agreements, Natural Protected Areas, and international agreements such as the Ramsar convention and the North American Wetlands Conservation Act. We present examples from the Gulf of California that highlight some of the challenges to wetland conservation. These challenges range from governmental failure to enforce existing environmental legislation, lack of verification of requirements for development projects, to low economic penalties for wetland modification or destruction. We found that in the Gulf of California successful conservation of coastal wetlands required a combination of policy instruments and relied on integrating science, management, and public participation through partnerships between non-governmental institutions, academic institutions, community stakeholders, and government agencies.     

GIS and the ‘Usual Suspects’-[Mis]understanding Land Use Change in Cambodia

GIS-RS techniques offer great potential for providing insights into the spatiality and temporality of the messy realties of deforestation. However, rather than positing that the land use maps produced using these novel technologies can cut through politics, it is argued that the map is merely an artifact of the broader process of land use planning which is constitutive of politics. This article critically reflects on a major land use mapping exercise that the two authors were involved with, in central Cambodia. It argues that GIS analysts need to go beyond merely a concern for ‘the local’, and have their own ‘honest’ teleologies that can navigate the complexities of environmental politics. This article shows how particular categorizations of land use that the analyst creates in accordance with their own desires and the technical limitations of GIS, are often bound up in techniques of government.     

Spatial and temporal movement of the Bearded Vulture using GPS telemetry in the Himalayas of Nepal

This study addresses for the first time the movement patterns of the globally near-threatened Bearded Vulture Gypaetus barbatus in its most important stronghold, the high-altitude mountain ranges of Asia. Tracked individuals (n = 8) in the Annapurna Himalayan range (Nepal) foraged over a vast range of 60 715.9 km² and our results indicated age-class differences in the use of space. Territorial adults showed very small annual home-ranges (K90 = 150.3 km²), whereas immatures wandered extensively and covered vast ranges of the mountains (K90 = 23 930.8 km²). For adults and immatures, these values are notably larger than the other two studied populations in the world (Pyrenees and South Africa). This suggests that the studied Annapurna population might exhibit lower breeding density than in the Pyrenees or South Africa, possibly due to lower food availability.     

Freezing of rat macrophages

The effect of freeze-thawing was studied in cryoprotected (10% dimethyl sulfoxide) rat peritoneal macrophages. Recovery after post-thaw washing was about 50%. Phagocytosis of latex particles seemed unhampered by this procedure, whereas the abilty to adhere to glass and the amount of Fc and C₃ receptors were moderately reduced. Low temperature preservation of macrophages might be a useful storage method, as it is for lymphocytes and tissue culture cells.     

Breeding habitat and nest-site selection of Bearded Vulture Gypaetus barbatus in the Annapurna Himalaya Range of Nepal

Quantitative studies on nesting habitat selection are important to understand and predict the resource requirements for breeding habitat. In this study, we analysed nest-site (cliff) and territory selection patterns of the Bearded Vulture in the Annapurna Range of the Himalayas (Nepal). Our study area represents high-elevation mountain range systems, where information on nest selection is lacking, despite having the largest remaining populations of Bearded Vultures in the world. Our models indicated selection patterns at both nest and territory spatial scales that are consistent with previous studies at lower altitudes (Pyrenees, the Caucasus), such as a preference for landscape patches with greater food availability. However, our models also indicated selection patterns that are probably a response to the higher altitudes and sheer reliefs of the Annapurna massif, such as avoidance of the steepest slopes and selection of cliffs facing south and west for nest-sites. We did not detect an impact of human activities on the distribution of nests or territories. However, the Annapurna massif is experiencing development of infrastructures (e.g. road construction). Further research efforts will be needed to monitor human impacts on Bearded Vulture populations in the Annapurna Range, as this is a global stronghold for this species.