1,655 research outputs found
Population genomic analysis of mango (Mangifera indica) suggests a complex history of domestication
Trust Humans have domesticated diverse species from across the plant kingdom, yet much of our foundational knowledge of domestication has come from studies investigating relatively few of the most important annual food crops. Here, we examine the impacts of domestication on genetic diversity in a tropical perennial fruit species, mango (Mangifera indica). We used restriction site associated DNA sequencing to generate genomic single nucleotide polymorphism (SNP) data from 106 mango cultivars from seven geographical regions along with 52 samples of closely related species and unidentified cultivars to identify centers of mango genetic diversity and examine how post-domestication dispersal shaped the geographical distribution of diversity. We identify two gene pools of cultivated mango, representing Indian and Southeast Asian germplasm. We found no significant genetic bottleneck associated with the introduction of mango into new regions of the world. By contrast, we show that mango populations in introduced regions have elevated levels of diversity. Our results suggest that mango has a more complex history of domestication than previously supposed, perhaps including multiple domestication events, hybridization and regional selection. Our work has direct implications for mango breeding and genebank management, and also builds on recent efforts to understand how woody perennial crops respond to domestication
Anisotropic Impurity-States, Quasiparticle Scattering and Nematic Transport in Underdoped Ca(Fe1-xCox)2As2
Iron-based high temperature superconductivity develops when the `parent'
antiferromagnetic/orthorhombic phase is suppressed, typically by introduction
of dopant atoms. But their impact on atomic-scale electronic structure, while
in theory quite complex, is unknown experimentally. What is known is that a
strong transport anisotropy with its resistivity maximum along the crystal
b-axis, develops with increasing concentration of dopant atoms; this
`nematicity' vanishes when the `parent' phase disappears near the maximum
superconducting Tc. The interplay between the electronic structure surrounding
each dopant atom, quasiparticle scattering therefrom, and the transport
nematicity has therefore become a pivotal focus of research into these
materials. Here, by directly visualizing the atomic-scale electronic structure,
we show that substituting Co for Fe atoms in underdoped Ca(Fe1-xCox)2As2
generates a dense population of identical anisotropic impurity states. Each is
~8 Fe-Fe unit cells in length, and all are distributed randomly but aligned
with the antiferromagnetic a-axis. By imaging their surrounding interference
patterns, we further demonstrate that these impurity states scatter
quasiparticles in a highly anisotropic manner, with the maximum scattering rate
concentrated along the b-axis. These data provide direct support for the recent
proposals that it is primarily anisotropic scattering by dopant-induced
impurity states that generates the transport nematicity; they also yield simple
explanations for the enhancement of the nematicity proportional to the dopant
density and for the occurrence of the highest resistivity along the b-axis
Botanical Description of Pigeonpea [Cajanus Cajan (L.) Millsp.]
Pigeonpea [Cajanus cajan (L.) Millspaugh] is an important legume crop of the papilionaceae family. It is an often cross-pollinated crop, and breeding principles of both self and cross-pollinated crops are highly effective in its genetic enhancement. Pigeonpea is a hard woody shrub, extensively adaptable to a range of soil types, temperature, and rainfall. It has a deep taproot system extending up to two meters and can grow to a height of four meters. Pigeonpea roots form a symbiotic association with Brady rhizobium spp. and perform biological nitrogen fixation. The branching pattern of stem may vary from bush type to compact upright type and is of determinate, semi-determinate, and non-determinate type based on the flowering pattern. The primary leaves are simple, opposite, and caduceus, while the latter ones are pinnately trifoliate with lanceolate to elliptical leaflets. Pigeonpea flowers are zygomorphic, borne on terminal or auxiliary racemes and are normally yellow in color with some variations. It has ten stamens in diadelphous condition with light or dark yellow anthers. The ovary is superior with a long style attached to a thickened, incurved, and swollen stigma. Pigeonpea is an often cross-pollinated crop with an average of 20% cross-pollination. The fruit of pigeonpea is called pod, which is of various colors, with and without deep constrictions. Seeds (with 20–22% proteins and amino acids) can be round or lens shaped, in shades of white and brown color with yellow color cotyledon. Pigeonpea is a widely consumed multi-utility pulse crop, thus the knowledge about the crop botany is vital for modifying it according to future challenges and goals
Medicinal Plant Use and Health Sovereignty: Findings from the Tajik and Afghan Pamirs
Medicinal plants are indicators of indigenous
knowledge in the context of political volatility and sociocultural
and ecological change in the Pamir Mountains of
Afghanistan and Tajikistan. Medicinal plants are the
primary health care option in this region of Central Asia.
The main objective of this paper is to demonstrate that
medicinal plants contribute to health security and sovereignty
in a time of instability. We illustrate the nutritional
as well as medicinal significance of plants in the daily
lives of villagers. Based on over a decade and half of
research related to resilience and livelihood security, we
present plant uses in the context of mountain communities.
Villagers identified over 58 cultivated and noncultivated
plants and described 310 distinct uses within
63 categories of treatment and prevention. Presence of
knowledge about medicinal plants is directly connected to
their use
Development of Core Set of Wheat (Triticum spp.) Germplasm Conserved in the National Genebank in India
Microwave response of superconducting pnictides: extended scenario
We consider a two-band superconductor with relative phase between the
two order parameters as a model for the superconducting state in
ferropnictides. Within this model we calculate the microwave response and the
NMR relaxation rate. The influence of intra- and interband impurity scattering
beyond the Born and unitary limits is taken into account. We show that,
depending on the scattering rate, various types of power law temperature
dependencies of the magnetic field penetration depth and the NMR relaxation
rate at low temperatures may take place.Comment: 11 pages, 5 figure
Genetic structure and differentiation in cultivated fig (Ficus carica L.)
One hundred ninety-four germplasm accessions of fig representing the four fig types, Common, Smyrna, San Pedro, and Caprifig were analyzed for genetic diversity, structure, and differentiation using genetic polymorphism at 15 microsatellite loci. The collection showed considerable polymorphism with observed number of alleles per locus ranging from four for five different loci, MFC4, LMFC14, LMFC22, LMFC31 and LMFC35 to nine for LMFC30 with an average of 4.9 alleles per locus. Seven of the 15 loci included in the genetic structure analyses exhibited significant deviation from panmixia, of which two showed excess and five showed deficiency of heterozygote. The cluster analysis (CA) revealed ten groups with 32 instances of synonymy among cultivars and groups differed significantly for frequency and composition of alleles for different loci. The principal components analysis (PCA) confirmed the results of CA with some groups more differentiated than the others. Further, the model based Bayesian approach clustering suggested a subtle population structure with mixed ancestry for most figs. The gene diversity analysis indicated that much of the total variation is found within groups (HG/HT = 0.853; 85.3%) and the among groups within total component (GGT = 0.147) accounted for the remaining 14.7%, of which ~64% accounted for among groups within clusters (GGC = 0.094) and ~36% among clusters (GCT = 0.053). The analysis of molecular variance (AMOVA) showed approximately similar results with nearly 87% of variation within groups and ~10% among groups within clusters, and ~3% among clusters. Overall, the gene pool of cultivated fig analyzed possesses substantial genetic polymorphism but exhibits narrow differentiation. It is evident that fig accessions from Turkmenistan are somewhat genetically different from the rest of the Mediterranean and the Caucasus figs. The long history of domestication and cultivation with widespread dispersal of cultivars with many synonyms has resulted in a great deal of confusion in the identification and classification of cultivars in fig
Grafting versus seed propagated apricot populations: two main gene pools in Tunisia evidenced by SSR markers and model-based Bayesian clustering
Apricot was introduced into the Mediterranean Basin from China and Asian mountains through the Middle-East and the Central Europe. Traditionally present in Tunisia, we were interested in accessing the origin of apricot species in the country, and in particular in the number and the location of its introductions. A set of 82 representative apricot accessions including 49 grafted cultivars and 33 seed propagated ‘Bargougs’ were genotyped using 24 microsatellite loci revealing a total of 135 alleles. The model-based Bayesian clustering analysis using both Structure and InStruct programs as well as the multivariate method revealed five distinct genetic clusters. The genetic differentiation among clusters showed that cluster 1, with only four cultivars, was the most differentiated from the four remaining genetic clusters, which constituted the largest part of the studied germplasm. According to their geographic origin, the five identified groups (north, centre, south, Gafsa oasis and other oases groups) enclosed a similar variation within group, with a low level of differentiation. Overall results highlighted the distinction of two apricot gene pools in Tunisia related to the different mode of propagation of the cultivars: grafted and seed propagated apricot, which enclosed a narrow genetic basis. Our findings support the assumption that grafting and seed propagated apricots shared the same origin
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
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