1,720,971 research outputs found
Discriminant Analysis of Morphological Descriptors to Differentiate the Opuntia Genotypes
No full textIn the present paper statistical procedures are considered to monitor the discriminating ability of descriptor variables, designed to characterize Opuntia spp. accessions, with the aim of identifying the most discriminating traits and provide a list of morphological characters of highest priority within the descriptors. Data from a set of 71 accessions of Opuntia spp. collected in 3 years of experimentation at the germplasm collection set up in Italy by the University of Sassari were analyzed. Accessions were characterized using 38 morphological descriptors evaluated in plant, cladodes and fruit, included in the FAO 'Descriptors for Cactus pear (Opuntia spp.)'. A discriminating analysis using a stepwise method was carried out to analyze the classificatory quantitative descriptors. For the qualitative descriptors, statistical comparisons were done by means of the chi-square (chi(2)) test. According to the analysis performed, only few descriptors have shown an effective discriminating capacity. Three quantitative fruit descriptors (recepticular scar diameter, seed number and pulp weight) and seven qualitative descriptors (cladodes shape, spines, fruits number, fruits size, recepticular scar position, peel and pulp colour) have been identified as differential parameters in Opuntia ficus-indica and O. amyclaea. However, a considerable number of descriptors among the 38 examined are relevant for the purpose of describing accessions and identifying traits connected to specific uses. Morphological characterization is needed to provide users valuable information on individual accessions, relationship among traits, and the structure of collections
Opuntia sp. Adaptability to the Mediterranean Environment
No full textThe relationships between Opuntia sp. and the Mediterranean environment of the island of Sardinia were studied based on the identification of the limiting ecological factors, using statistical techniques and GIS software. In 100 test-sites, representative of the area variability, Opuntia sp. populations were morphologically and genetically characterized. GIS application was implemented to analyze, update and encode all collected data, thus enabling thematic maps to be drawn. FloraMap, a specific GIS application, was successfully used to predict the Opuntia sp. distribution in Sardinia
Identification of Microsatellite Loci in Opuntia spp. and Their Characterization in Cultivars and Species
No full text"We report on the development of 10 microsatellites isolated from Opuntia ficus-indica. To evaluate the degree of polymorphism of these markers, a range of cultivars from the germplasm collection established at the Experimental Station of the University of Sassari has been tested. DNA from 12 Opuntia species was also used to test transferability of the developed primers. The level of polymorphism and the relatively high number of alleles detected ranging from 6 to 22 suggest that these markers can be used for both inter- and intra-specific studies, as well as to analyze the polyploidy occurrence in Opuntia.
Applicazione di marcatori molecolari per la caratterizzazione di genotipi di Myrtus communis L
No full textSSR Markers Analysis of the Sardinian Grape Germplasm
No full textSardinia has an ancient history as a secondary grape domestication centre, having developed a wide variety of different Vitis cultivars that lasts nowadays. Our work focused on giving a molecular basis of identification, through SSR, over this large genetic pool as a conservation strategy to manage field collection at local level. A set of 146 accessions including local, national and international cultivars was adopted. The genotyping of the grape collection held in Sardinia revealed a relatively high genetic variation. Eleven groups of synonyms and unknown local accessions were identified. Information on duplicates and incorrect denomination is also provided
Spatial analysis of gypsy moth populations in Sardinia using geostatistical and climate models
No full text1 Spatial fluctuations of the Sardinian population of the gypsy moth Lymantria dispar
(L.) (Lepidoptera: Lymantriidae) were characterized using geostatistical and climate
models. Data on gypsy moth egg mass abundance recorded at 282 permanent
monitoring sites from 1980 to 2004 were incorporated in a geographic information
system with the vegetational, geomorphological and pedological features of the sites.
2 Statistical analyses revealed that the relative outbreak frequency was related to the
predominant host tree, slope and elevation of the monitoring sites, whereas there
was no correlation between outbreak frequency and exposure and soil type.
3 By using bioclimatic modelling, probability maps of gypsy moth outbreaks were
generated. The model identified a probability surface with climatic conditions
favourable to gypsy moth outbreaks and thus potentially subject to defoliation.
The maps included 92 sites where outbreaks never occurred, suggesting that the
Sardinian climate may not be a determinant factor for gypsy moth outbreaks.
4 The geostatistical method cokriging with outbreak frequency as a covariate was
found to be the most suitable technique to estimate gypsy moth egg mass abundance.
Semivariograms showed spatial correlation of egg mass abundance within the
range 18.5–53 km. The results obtained were used to create regional gypsy moth
distribution maps by cokriging, which demonstrated the outbreak foci and different
infestation levels at each monitoring area. These results can help to delimit the
treatment areas and develop rational gypsy moth management programmes
Analisi dell’influenza della temperatura sulla distribuzione spaziale di Lymantria dispar (L.) in Sardegna tramite tecniche geostatistiche e GIS
No full textOpuntia sp adaptability to the Mediterranean environment
No full textThe relationships between Opuntia sp. and the Mediterranean environment of the island of Sardinia were studied based on the identification of the limiting ecological factors, using statistical techniques and GIS software. In 100 test-sites, representative of the area variability, Opuntia sp. populations were morphologically and genetically characterized. GIS application was implemented to analyze, update and encode all collected data, thus enabling thematic maps to be drawn. FloraMap, a specific GIS application, was successfully used to predict the Opuntia sp. distribution in Sardinia
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