Search

In dry southwestern South Tyrol, Italy, rock glaciers are dominant landforms of the high-mountain cryosphere. Their spatial distribution and degree of activity hold critical information on the current state of discontinuous permafrost and consequently on the response potential to climate warming. Traditional geomorphologic mapping, however, owing to the qualitative expert-based nature, typically displays a high degree of uncertainty and variability among operators with respect to the dynamic classification of intact (permafrost-bearing) and relict (permafrost-devoid) rock glaciers. This limits the reliability of geomorphologic rock glacier inventories for basic and applied purposes. To address this limitation, (i) we conduct a systematic evaluation of the improvements that synthetic aperture radar interferometry (InSAR) can afford to the detection and dynamic classification of rock glaciers and (ii) build an integrated inventory that combines the strengths of geomorphologic- and InSAR-based approaches. To exploit fully InSAR-based information towards a better understanding of the topo-climatic conditions that sustain creeping permafrost, we further explore how velocity and the spatial distribution of moving areas (MAs) within rock glaciers may vary as a function of simple topographic variables known to exert first-order controls on incoming solar radiation, such as elevation and aspect. Starting from a geomorphologic inventory (n=789), we characterize the kinematics of InSAR-based MAs and the relevant hosting rock glaciers on 36 Sentinel-1 interferograms in the 2018–2019 period. With respect to the original inventory, InSAR analysis allowed us to identify 14 previously undetected rock glaciers. Further, it confirmed that 246 (76 %) landforms, originally interpreted as intact, do exhibit detectable movement (i.e., ≥1 cm yr -1) and that 270 (60 %) of the relict labeled counterparts do not, whereas 144 (18 %) were kinematically undefined due to decorrelation. Most importantly, InSAR proved critical for reclassifying 121 (15 %) rock glaciers, clarifying that 41 (13 %) of those interpreted as being intact do not exhibit detectable movement and that 80 (17 %) of the original relict ones do move. Reclassification (i) allowed us to identify a cluster of intact rock glaciers below 2000 m a.s.l. associated with positive mean annual air temperature (MAAT), and (ii) by increasing the altitudinal overlap between intact and relict rock glaciers, it depicts a broad transition belt in the aspect–elevation space, which varies from 50 m on west-facing slopes to 500 m on easterly ones. This finding deteriorates the significance of elevation and aspect as topographic proxies for modeling permafrost occurrence and highlights the importance of using InSAR to inform such models. From a process-oriented standpoint, InSAR information proves fundamental for imaging how this altitudinal transition manifests through changing rates and styles of rock glacier surface deformation. Specifically, we find that, as rock glaciers move faster, an increasingly larger proportion of their surface becomes kinematically involved (i.e., percent MA cover) and that this proportion increases with elevation up to 2600–2800 m, beyond which an inflection occurs and consistent average values are attained. Considering that the inflection falls between the -1 and -2 °C MAAT – the lower boundary for discontinuous permafrost – and is independent of slope gradient, we conclude that this altitudinal pattern represents a geomorphic signature: the dynamic expression of increasing permafrost distribution, from sporadic to discontinuous. [ABSTRACT FROM AUTHOR]

The kinematic acceleration of rock glaciers observed in recent decades shows that the behavior of these landforms is related to climate change. Velocity variations on yearly to seasonal time scales are frequently investigated, but velocity changes measured on shorter time scales (i.e., on hourly resolutions) are as yet poorly investigated. We used a ground based synthetic aperture radar to investigate, on an hourly time scale, the displacement of a rock glacier located in Val Senales (European Alps, northern Italy). We observed velocity fluctuations occurring at a very regular pace, characterized by phases of sharp acceleration (up to 0.9 mm/hr) lasting 4–11 hr followed by long phases of stagnation lasting 13–20 hr. This study describes an unprecedented observation of an hourly velocity rhythm of an active rock glacier and opens up new perspectives in the analysis and interpretation of rock glacier kinematics. Plain Language Summary: Rock glaciers are debris landforms commonly found in mountain permafrost environments. Active rock glaciers slowly move downslope, and their kinematics is related to the internal structure and driven by external factors associated with the climatic variables. Rock glacier velocity varies on different time scales, from millennial to annual, and their movement can be observed using a range of techniques. We measured velocity variations of an active rock glacier in the eastern European Alps on an hourly time scale, by using a ground based synthetic aperture radar. For the first time, we documented a peculiar kinematic behavior for a rock glacier, showing a "step‐like" cumulative movement associated with velocity peaks occurring at a regular daily rhythm. The internal processes driving the kinematics of rock glaciers are still not fully understood, and further investigations are needed to clarify the main reasons for the pattern observed in this study. Our unique data provide a new perspective to improve understanding of rock glacier kinematics and their recent velocity acceleration driven by climate change. Key Points: We used terrestrial radar interferometry to measure the displacement of an active rock glacier on an hourly time scaleWe observed velocity peaks lasting 4–11 hr, separated by phases of stagnation lasting 13–20 hrThe velocity peaks were observed to have a regular rhythm during the investigated period [ABSTRACT FROM AUTHOR]

Rock glaciers are landforms related to permafrost creep that are sensitive to climate variability and change. Their spatial distribution and kinematic behaviour can be critical for managing water resources and geohazards in periglacial areas. Rock glaciers have been inventoried for decades worldwide, often without assessment of their kinematics. The availability of remote sensing data however makes the inclusion of kinematic information potentially feasible, but requires a common methodology in order to create homogeneous inventories. In this context, the International Permafrost Association (IPA) Action Group on rock glacier inventories and kinematics (2018–2023), with the support of the European Space Agency (ESA) Permafrost Climate Change Initiative (CCI) project, is defining standard guidelines for the inclusion of kinematic information within inventories. Here, we demonstrate the feasibility of applying common rules proposed by the Action Group in 11 regions worldwide. Spaceborne interferometric synthetic aperture radar (InSAR) was used to characterise identifiable moving areas related to rock glaciers, applying a manual and a semi-automated approach. Subsequently, these areas were used to assign kinematic information to rock glaciers in existing or newly compiled inventories. More than 5000 moving areas and more than 3600 rock glaciers were classified according to their kinematics. The method and the preliminary results were analysed. We identified drawbacks related to the intrinsic limitations of InSAR and to various applied strategies regarding the integration of non-moving rock glaciers in some investigated regions. This is the first internationally coordinated work that incorporates kinematic attributes within rock glacier inventories at a global scale. The results show the value of designing standardised inventorying procedures for periglacial geomorphology. [ABSTRACT FROM AUTHOR]

Abstract: Nine commercial potato cultivars have been analyzed in order to detect differences in nutritional quality, considering the balance between nutrients and anti-nutrient compounds present in each. The most important nutrients studied in this paper were: water, starch, free sugars, such as glucose, fructose and sucrose, malic acid, citric acid, ascorbic acid and chlorogenic acid. The anti-nutrients measured included α-solanine, α-chaconine and asparagine. This last compound was added to the anti-nutrient compounds because it is involved in the formation of acrylamide during thermal food processes. From this study, by considering the nutritional quality of each cultivar, we can divide the potato cultivars into three groups, each being suitable for a different technological processes. [Copyright &y& Elsevier]

Rock glaciers are widespread periglacial landforms in mountain regions like the European Alps. Depending on their ice content, they are characterized by slow downslope displacement due to permafrost creep. These landforms are usually mapped within inventories, but understand their activity is a very difficult task, which is frequently accomplished using geomorphological field evidences, direct measurements, or remote sensing approaches. In this work, a powerful method to analyze the rock glaciers' activity was developed exploiting the synthetic aperture radar (SAR) satellite data. In detail, the interferometric coherence estimated from Sentinel-1 data was used as key indicator of displacement, developing an unsupervised classification method to distinguish moving (i.e., characterized by detectable displacement) from no-moving (i.e., without detectable displacement) rock glaciers. The original application of interferometric coherence, estimated here using the rock glacier outlines as boundaries instead of regular kernel windows, allows describing the activity of rock glaciers at a regional-scale. The method was developed and tested over a large mountainous area located in the Eastern European Alps (South Tyrol and western part of Trentino, Italy) and takes into account all the factors that may limit the effectiveness of the coherence in describing the rock glaciers' activity. The activity status of more than 1600 rock glaciers was classified by our method, identifying more than 290 rock glaciers as moving. The method was validated using an independent set of rock glaciers whose activity is well-known, obtaining an accuracy of 88%. Our method is replicable over any large mountainous area where rock glaciers are already mapped and makes it possible to compensate for the drawbacks of time-consuming and subjective analysis based on geomorphological evidences or other SAR approaches. [ABSTRACT FROM AUTHOR]

Rock glacier inventories have been created for many mountainous regions in Europe and outside in the past decades. These GIS-based catalogues are an important source of information to investigate periglacial landscapes, such as exploring associations between permafrost phenomena and environmental conditions. In this context, a crucial information stored in rock glacier inventories are the activity status and the related ice content of the mapped landforms ("active", "inactive", "intact" or "relict", and "fossil"). The assignment of the activity status is mostly done by individual operators based on morphological evidences found in the field, on aerial images and on digital terrain models, in some cases by field measurements with different methods. Even though this expert-based approach has proven to be highly valuable, it is also known to be time consuming and somewhat subjective concerning especially the definition of the status of the rock glaciers. Recent technological advances in satellite remote sensing techniques - coupled to new algorithms for multiple variable analysis - offer new possibilities for improving rock glacier classification. This study presents a novel, two-step approach to divide first moving from not moving rock glaciers, and subsequently to separate ice-cored from ice-free rock glaciers. This approach combines remote sensing with statistical computing and proposes an integration scheme that enables to combine the advantages of these both methodologies. The study was conducted in South Tyrol (Northern Italy), a region for which a comprehensive rock glacier inventory was made available by the local administration.In the first step, a stack of multi-temporal SAR Sentinel 1A/B-images were processed to obtain coherence changes within each rock glacier present in the inventory. Exploiting the relation between coherence and displacement, an unsupervised classification has been developed. Rock glaciers were divided into "non-moving" forms (i.e. those without detectable displacement and thus including inactive, intact, relict or fossil categories) and "moving" ones (i.e. those with detectable displacement and corresponding to active rock glaciers). This first step takes into account only the kinematic aspects, without considering the permafrost ice content.The second step is based on a supervised classification of the rock glacier status using statistically-based and machine-learning algorithms. A set of environmental variables, which in literature were found to be indicative about the ice content of rock glaciers, were used to build several multiple-variable models. This operation produces a binary classification of rock glaciers: those featuring a relevant ice content (i.e. including both active and intact types) and those with only sparse to null ice (i.e. relict and fossil types).Finally, the integration of the two steps described above leads to the following classification: "currently moving" and "high ice content" = "active"; "not moving" and "high ice content" = "intact"; "not moving" and "sparse ice content" = "relict"; "not moving" and "no ice content" = "fossil". [ABSTRACT FROM AUTHOR]

Background: Opportunity and challenges of the agriculture scenario of the next decades will face increasing demand for secure food through approaches able to minimize the input to cultivations. Large panels of tomato varieties represent a valuable resource of traits of interest under sustainable cultivation systems and for genome-wide association studies (GWAS). For mapping loci controlling the variation of agronomic, fruit quality, and root architecture traits, we used a heterogeneous set of 244 traditional and improved tomato accessions grown under organic field trials. Here we report comprehensive phenotyping and GWAS using over 37,300 SNPs obtained through double digest restriction-site associated DNA (dd-RADseq). Results: A wide range of phenotypic diversity was observed in the studied collection, with highly significant differences encountered for most traits. A variable level of heritability was observed with values up to 69% for morphological traits while, among agronomic ones, fruit weight showed values above 80%. Genotype by environment analysis highlighted the strongest genotypic effect for aboveground traits compared to root architecture, suggesting that the hypogeal part of tomato plants has been a minor objective for breeding activities. GWAS was performed by a compressed mixed linear model leading to 59 significantly associated loci, allowing the identification of novel genes related to flower and fruit characteristics. Most genomic associations fell into the region surrounding SUN, OVATE, and MYB gene families. Six flower and fruit traits were associated with a single member of the SUN family (SLSUN31) on chromosome 11, in a region involved in the increase of fruit weight, locules number, and fruit fasciation. Furthermore, additional candidate genes for soluble solids content, fruit colour and shape were found near previously reported chromosomal regions, indicating the presence of synergic and multiple linked genes underlying the variation of these traits. Conclusions: Results of this study give new hints on the genetic basis of traits in underexplored germplasm grown under organic conditions, providing a framework for the development of markers linked to candidate genes of interest to be used in genomics-assisted breeding in tomato, in particular under low-input and organic cultivation conditions. [ABSTRACT FROM AUTHOR]

Background: Opportunity and challenges of the agriculture scenario of the next decades will face increasing demand for secure food through approaches able to minimize the input to cultivations. Large panels of tomato varieties represent a valuable resource of traits of interest under sustainable cultivation systems and for genome-wide association studies (GWAS). For mapping loci controlling the variation of agronomic, fruit quality, and root architecture traits, we used a heterogeneous set of 244 traditional and improved tomato accessions grown under organic field trials. Here we report comprehensive phenotyping and GWAS using over 37,300 SNPs obtained through double digest restriction-site associated DNA (dd-RADseq). Results: A wide range of phenotypic diversity was observed in the studied collection, with highly significant differences encountered for most traits. A variable level of heritability was observed with values up to 69% for morphological traits while, among agronomic ones, fruit weight showed values above 80%. Genotype by environment analysis highlighted the strongest genotypic effect for aboveground traits compared to root architecture, suggesting that the hypogeal part of tomato plants has been a minor objective for breeding activities. GWAS was performed by a compressed mixed linear model leading to 59 significantly associated loci, allowing the identification of novel genes related to flower and fruit characteristics. Most genomic associations fell into the region surrounding SUN, OVATE, and MYB gene families. Six flower and fruit traits were associated with a single member of the SUN family (SLSUN31) on chromosome 11, in a region involved in the increase of fruit weight, locules number, and fruit fasciation. Furthermore, additional candidate genes for soluble solids content, fruit colour and shape were found near previously reported chromosomal regions, indicating the presence of synergic and multiple linked genes underlying the variation of these traits. Conclusions: Results of this study give new hints on the genetic basis of traits in underexplored germplasm grown under organic conditions, providing a framework for the development of markers linked to candidate genes of interest to be used in genomics-assisted breeding in tomato, in particular under low-input and organic cultivation conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND The consumers' perception of the importance of healthy food has promoted the interest towards fruit, vegetables and spices rich in antioxidants. Moreover, changing in eating habits has encouraged the diffusion of ready‐to‐eat commodities with specific merceological standards. In the present study, 12 hot pepper varieties devoted to powder production, canned processing, blister packaging have been evaluated for morpho‐agronomic traits and bioactive compounds in replicated trials in three locations and two growing seasons. RESULTS: For all traits, the genotypic component (G) and the genotype × location interaction (G×L) were significant (P < 0.05). Morphological fruit traits evidenced a strong effect of the genotype (> 95%) while yield and biochemical traits showed a variable response to environmental effects. Capsaicin and the yellow fraction of carotenoids were the only nutraceutical compounds showing a relatively high G effect, contrariwise, ascorbic acid, carotenoids and tocopherols were more influenced by location (L) and year of cultivation (Y). Results showed how breeding for quality traits in chilli is still challenging. Multivariate analysis allowed to identify pairs of traits distinguishing the different market typologies: powder types exhibited a lower productivity and higher pungency while those for blister packaging had a remarkable antioxidant capacity. CONCLUSIONS: A comprehensive approach was used to study the plasticity of agronomic and nutritional traits in chilli pepper. The set of cultivars analysed produced fruits with considerable levels of several health‐related metabolites, including capsaicin, carotenoids and antioxidant phytochemicals. This information is useful for precision breeding of novel varieties. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Local varieties represent a heritage for plant biodiversity and, thanks to their resilience, are characterized by a better adaptation and rusticity to environmental variables. This work reports the morphological and physiological responses of a local ecotype of sweet pepper grown in Southern Italy, i.e., Altino, to N and light supplied at optimal and sub-optimal levels. In 2017, two open-field experiments were set up, comparing increasing N rates (0, 100 and 200 kg N ha−1, 0_N, 100_N and 200_N, respectively) and different percentages of shading and/or manipulations of the transmitted solar radiation, obtained through photoselective nets (red net, RN; black net, BN; unshaded Control). The unfertilized plants reduced growth (by 32% on average, at 83 days after transplanting, DAT), especially in terms of number of leaves, leaf area and effectiveness (chlorophyll content) of photosynthetic apparatus; no differences were recorded among fertilization treatments. On the other hand, the shading avoidance mechanisms resulted in higher biomass partitioned to leaves at the expense of sink organs, the building of more expanse (higher total leaf area) and thinner (higher specific leaf area and lower leaf-cuticular waxes) photosynthetic apparatus, and in a greater concentration of leaf pigments. The effects on yield and fruit quality of Altino ecotype deserve to be further explored. [ABSTRACT FROM AUTHOR]