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991.
992.
Abderrazek Jilal Stefania Grando Robert J. Henry L. Slade Lee Nicole Rice Helen Hill Michael Baum Salvatore Ceccarelli 《Genetic Resources and Crop Evolution》2008,55(8):1221-1230
Twenty genic- and genomic SSR markers were used to study genetic diversity and geographical differentiation of barley from 29 countries through analysis of a worldwide collection of 304 ICARDA’s barley landraces. Of these, 19 loci were highly polymorphic in the material studied. Based on Nei-distance matrix, Principal Component Analysis (PCoA) and cluster analysis using UPGMA associated with AMOVA the data revealed countries’ grouping within regions. Three distinct germplasm pools were identified in the landraces. The first of these was from Eastern Africa (Eritrea and Ethiopia) and South America (Ecuador, Peru and Chile) suggesting that barley introduced to South America might have originated specifically from East Africa or that they share a common genetic basis for adaptation. The second was the Caucasus (Armenia and Georgia) and the third included the remaining regions of Central Asia, Near East, Northern Africa and Eastern Asia. Genetic diversity of barley subspecies (Six-rowed barley, Two-rowed barley, H. spontaneum C. Koch and H. agriocrithon Åberg) also discriminates them into three groups: cultivated barleys (Six-rowed barley and Two-rowed barley), wild barley H. spontaneum and subspecies H. agriocrithon. These results associated with parsimony analysis demonstrate that H. agriocrithon and H. spontaneum might be distinct and do not support a hybrid origin for H. agriocrithon suggesting further investigation of the basis of more intense sampling of the two subspecies H. spontaneum and H. agriocrithon. 相似文献
993.
994.
A. S. M. G. Masum Akond N. Watanabe Y. Furuta 《Genetic Resources and Crop Evolution》2008,55(1):133-141
Genetic diversity of a set of introgression lines of Triticum aestivum L./T. polonicum L. with long glume and T. petropavlovskyi Udacz. et Migusch. were analyzed by Amplified Fragments Length Polymorphism (AFLP). Small-scale bulk breeding method was
applied throughout until F6 generation to develop the introgression lines. Thirty-eight hexapolid F7 plants with long glume phenotype and their parents were subjected to AFLP analysis by four primer combinations. A total of
47 polymorphic loci were detected between the parents, 15 of them were introgressed across the 38 lines. It was hypothesized
that approximately 50% of A or B genomes associated polymorphic loci were introgressed. The variation of introgression lines
was limited within the diversity between their parents, T. aestivum L. cv. Novosibirskaya 67 (N67) and T. polonicum L. cv. IC12196. N67 was closer to 38 introgression lines than that of IC12196. The UPGMA cluster and principal coordinate
analysis (PCO) grouping showed 0.84 to 0.98 similarity values between N67 and the introgression lines. Eleven T. petropavlovskyi accessions were distinguished from introgression lines with UPGMA clusters and PCO groupings, and T. petropavlovskyi was located between the introgressions lines and IC12196. Several introgression lines resembled with T. petropavlovskyi for awning and glume length. The genetic variation among 38 introgression lines was much wider than that of T. petropavlovskyi. We concluded that T. petropavlovskyi was established by intensive selection of hybrid between T. aestivum/T. polonicum. 相似文献
995.
Gerard Allan Amber Williams Pablo D. Rabinowicz Agnes P. Chan Jacques Ravel Paul Keim 《Genetic Resources and Crop Evolution》2008,55(3):365-378
Worldwide genetic diversity in 200 individuals comprising 41 castor bean accessions was assessed using amplified fragment
polymorphisms (AFLPs) and simple sequence repeats (SSRs). We found that, despite surveying five continents and 35 countries,
genetic diversity in castor bean germplasm is relatively low (overall H
e = 0.126 for AFLPs and 0.188 for SSRs) compared to estimates of genetic diversity in other plant species. Our data also show
no geographic structuring of genotypes across continents or countries within continents. An assessment of the congruence between
AFLP and SSRs indicates a low correlation (R
2 = 0.19) between the two data sets, but each marker class nonetheless shows similar patterns of low-genetic diversity and
a lack of geographic structure. Our data do suggest that SSRs yield a higher percentage of polymorphic loci, higher heterozyosity
and a greater range of genetic distances, and are therefore more informative than are AFLPs on a locus-by-locus basis. Based
on comparisons with numerous other plant species, we suggest that the lower genetic variation in this worldwide collection
may be due to one or more factors including: sampling strategies that have not captured the full extent of genetic variation
in the species; artifactual variation due to long-term germplasm storage and seed regeneration; or intense selection followed
by domestic cultivation of a limited number of castor bean genotypes, which are widely propagated for their horticultural
and agro-economic value. 相似文献
996.
A wild tetraploid oat Avena maroccana Gdgr. was collected from the 11 populations in the periphery of Rommani and Casablanca geographic groups of Morocco. Genetic
diversity of the species was investigated using six allozyme systems. Allelic frequencies were scored representing eight polymorphic
and five monomorphic loci. Coefficient of gene differentiation (Gst) was 0.3019, which indicated great genetic differentiation. The number of alleles per locus was 2.6154, the percentage of
polymorphic loci was 61.54, and the expected heterozygosity was 0.2462 in all populations. Genetic diversity in A. maroccana was high in comparison to self-pollinated species. In total, nine heterozygotes resulting from outcrossing were found in
the progeny from M1, M3, M4, M22 and M26. The population of M7 had peculiar alleles Pgd–2SS and Pgd-1SS in high frequency. M9 had the lowest level of diversity out of the 11 populations. Geographic and genetic distances between
all the populations were not significantly correlated with each other (r = 0.0996). Cluster analysis showed that two groups, (M1, M22, M2 and M4) and (M3, M23, M8, M5 and M26) were apparently differentiated.
Two populations of the Casablanca group, M7 and M9 were independent from each other, and were separated distinctly from the
other populations. Genetic diversity of the Rommani and Casablanca groups was almost the same in all the parameters. This
was due to the similar man-made habitat such as roadside or rich fertile soil and brown clay soils. The population size of
A. maroccana was small and restricted to the narrow central Morocco with great genetic differentiation so that genetic diversity may be
reflected from the results of genetic drift and outcrossing heterozygote segregation. 相似文献
997.
Carine Hue Marie Tremblay Daniel Wallach 《Journal of Agricultural, Biological & Environmental Statistics》2008,13(3):355-365
Bayesian methods seem well adapted to dynamic system models in general and to crop models in particular, because there is
in general prior information about parameter values. The usefulness of a Bayesian approach has often been pointed out, but
actual applications are rather rare. A major difficulty is including the elements of the covariance matrix of model errors
in the treatment. We treat the specific case of balanced data and an unstructured covariance matrix. In our particular case
this is a 3 × 3 matrix. We illustrate two methods for deriving a sample from the joint posterior density for the crop model
parameters and the error covariance matrix parameters. The first method is based on importance sampling, the second on Metropolis
within Gibbs sampling. We derive an instrumental density for the former and a proposal density for the latter which are adapted
to this type of model and data. Both algorithms work well and they give very similar results. The example concerns a model
for sunflowers during rapid leaf growth. The ultimate goal is to use the model as a decision aid in predicting disease risk. 相似文献
998.
Kinh Bac Dang Benjamin Burkhard Felix Müller Van Bao Dang 《Paddy and Water Environment》2018,16(4):767-781
Land use change due to the development of agriculture and community-based tourism has resulted in an increase in natural hazards (e.g. erosion and landslides) that affect sustainability in the Sapa mountainous area in northern Vietnam. Natural hazard regulating ecosystem services have protected the local people from the destruction of their villages, goods and natural resources, especially in the rainy season. However, it is difficult to identify which kinds of anthropogenic constructions support a co-production of regulating services in human-influenced social–ecological systems and in which specific types of land use and land cover the supply of such services takes place, especially in heterogeneous mountainous areas. Therefore, this research attempts to (1) distinguish between the potential and actual use (flow) of natural hazard regulating ecosystem services and (2) understand how soil erosion and landslide regulating ecosystem services can contribute to a sustainable management of different ecosystems, especially in rice fields and forest areas. Two models (InVEST for soil erosion, Analytic Hierarchy Process for landslide analysis) were used to analyze and map the contributions of natural versus anthropogenic components for regulating natural hazards in Sapa. The results show the incoherent distribution of erosion regulating services and low capacities of landslide regulating services in areas that have seriously been affected by human activities, especially forestry and agricultural development. The contribution of rice ecosystems to soil erosion mitigation is higher than in the case of landslides. Nevertheless, one-third of the area of paddy fields in the case study area have “no” capacity to supply natural hazard regulating ecosystem services and should therefore be re-forested. 相似文献
999.
1000.
Majid Salehi Ahmad Vaez Mahdi Naseri-Nosar Saeed Farzamfar Arman Ai Jafar Ai Shima Tavakol Mehrdad Khakbiz Somayeh Ebrahimi-Barough 《Fibers and Polymers》2018,19(1):125-134
In the present study, naringin, a flavonoid isolated from the grape and citrus fruit species, was incorporated with poly(ε-caprolactone)/gelatin composite mats in order to develop a potential wound dressing. The composite mats were prepared by electrospinning of poly(ε-caprolactone)/gelatin (1:1 (w/w)) solution incorporated with 1.50 %, 3 % and 6 % (w/w) of naringin. The electrospun mats were evaluated regarding their morphology, contact angle, water-uptake capacity, water vapor transmission rate, tensile properties, drug release, cellular response and in vivo wound healing activity. The study showed that after 2 weeks, the full-thickness excisional wounds of Wistar rats treated with the naringin-loaded dressings achieved a wound closure of higher than 94 % and the dressing containing 6 % (w/w) naringin had almost 100 % wound closure. The sterile gauze, as the control group, showed nearly 86 % of wound closure after this period of time. Our results provided evidence that supports the possible applicability of naringin-loaded wound dressing for successful wound treatment. 相似文献