Search results for "forestry"
showing 10 items of 1998 documents
Fragmentation and local disturbance of forests reduce frugivore diversity and fruit removal in Ficus thonningii trees
2008
Clearance, fragmentation, and degradation of tropical forests have resulted in declines of biodiversity. This loss of biodiversity is endangering important ecosystem processes such as seed dispersal. If anthropogenic disturbances affect seed dispersal of keystone plants, effects on tropical ecosystems might be especially pronounced. We studied frugivore assemblages and fruit removal from 25 Ficus thonningii trees in the heavily fragmented and disturbed Kakamega Forest, western Kenya. During 400 observation hours we recorded 36 frugivores visiting F. thonningii trees. We recorded significantly fewer frugivorous species in fragments compared to the main forest and in highly, compared to littl…
Analysis of Geometrical Relationships and Friction Losses in Small-Diameter Lay-Flat Polyethylene Pipes
2016
[EN] The use of lay-flat polyethylene pipes to irrigate horticultural crops has been receiving widespread attention in the last decade, due to the significant improvements in their hydraulic performance, their potentially high application efficiency, and their limited installation costs. However, even if hydraulic design procedures for conventional microirrigation systems are fairly well established, there is still the need to know how different pipe-wall thicknesses of lay-flat pipes can affect the pipe geometry under different operating pressures as well as the related consequences on friction losses. This paper, after comparing two different procedures (caliper and photographic) to asses…
Classification of varieties for their timing of flowering and veraison using a modelling approach: A case study for the grapevine species Vitis vinif…
2013
16 pages; International audience; tUnderstanding differences in phenology for varieties of a given species is important for making informeddecisions on variety choice in the context of climate change and breeding new cultivars. Phenologicalmodels that incorporate temperature as a key environmental factor can be used to describe the differencesin phenological timing between cultivars. This paper outlines a methodology, based on a phenologicalmodel, for classifying the timing of flowering and veraison for a substantial number of varieties of thegrapevine (Vitis vinifera L.). 95 varieties were characterized for flowering and 104 varieties for veraison.Various statistical measures were used to …
THE ROLE OF MEDITERRANEAN FRUIT TREE ORCHARDS AND VINEYARDS IN MAINTAINING THE TRADITIONAL AGRICULTURAL LANDSCAPE
2012
The Mediterranean area represents one of the most suitable and diversified environments for horticultural crops, being this propriety well expressed in the commonly accepted definition of “Mediterranean cultivated garden”. In Italy, fruit crops have been in the past introduced and expanded in different environments depending on the species and adaptability to the physiographic characteristics of the regions. The climate and the diversity of environmental contexts, the specificity of soils, the plasticity of the cultivated genotypes, have allowed a tight and typical relationship among land and farmers. Since the past centuries olive and fruit orchards, vineyards and Citrus plantations have r…
Analysis of Chemical and Biochemical Parameters of Petrol-Contaminated Soil after Biostimulation with an Enzyme Reagent
2020
This study aimed to assess the effect of petrol and the Fyre Zyme reagent on selected chemical and biochemical properties of loamy sand. The experiment was conducted under laboratory conditions. First, petrol was introduced into the soil at doses of 0 and 50 g k-1dry matter (DM). Next, 6% Fyre-Zyme enzyme reagent solution was added to the samples contaminated and uncontaminated with petrol, in the following combinations: 0 (control), once at 40 cm3 kg&ndash
Chromosomal variation and genome size support existence of cryptic species of Triatoma dimidiata with different epidemiological importance as Chagas …
2006
Summary The wide geographical distribution of Triatoma dimidiata, one of the three major vectors of Chagas disease, ranges from Mexico to northern Peru. Since this species occupies a great diversity of artificial and natural ecotopes, its eradication is extremely difficult. In order to assist control efforts, we used chromosome analyses and DNA amount as taxonomic markers to study genetic variability in populations of T. dimidiata from Mexico, Guatemala, El Salvador and Colombia. We differentiated three groups or cytotypes defined by characteristic chromosome C-banding patterns and genome size measured by flow cytometry. The three cytotypes are restricted to different geographic locations. …
Genetic Diversity, Population Size, and Fitness in Central and Peripheral Populations of a Rare Plant Lychnis viscaria
1999
: Genetic diversity is expected to decrease in small and isolated populations as a consequence of bottlenecks, founder effects, inbreeding, and genetic drift. The genetics and ecology of the rare perennial plant Lychnis viscaria (Caryophyllaceae) were studied in both peripheral and central populations within its distribution area. We aimed to investigate the overall level of genetic diversity, its spatial distribution, and possible differences between peripheral and central populations by examining several populations with electrophoresis. Our results showed that the level of genetic diversity varied substantially among populations ( Hexp = 0.000–0.116) and that the total level of genetic …
Resistant management of Bt corn and sustainability in Italy
2006
The Resistant Management (RM) of Bt corn in US requires 20% refuge area planted with non transgenic maize to preserve susceptible individuals of the pest. In Europe, especially in Italy, different considerations are necessary when RM plans are to be applied. In fact, when determining the size of the refuge areas other aspects around the transgenic corn, such as the surface of co-existing plans and other crops, must be considered. ECB is a polyphagous insect and its biology must be taken into account in the RM, especially in Italy where several crops and natural areas exist close to each other, and where field surfaces are clearly smaller than in the US. An important aspect of RM is the dete…
Development of “universal” gene-specific markers from Malus spp. cDNA sequences, their mapping and use in synteny studies within Rosaceae
2009
The Rosaceae contains many economically valuable crop genera, including Malus (apple), Fragaria (strawberry), and Prunus (stone fruit). There has been increasing interest in the development of linkage maps for these species, with a view to marker-assisted selection to assist breeding programs and, recently, in the development of transferable markers to permit syntenic comparisons of maps of different rosaceous genera. In this investigation, a set of Malus cDNA sequences were downloaded from the European Molecular Biology Laboratory database. The sequences were aligned with homologous full-length Arabidopsis genomic DNA sequences to identify putative intron–exon junctions and conserved flank…
Intra-allelic variation in introns of the S13-RNase allele distinguishes sweet, wild and sour cherries
2010
The cherry (Prunus avium), a self-incompatible diploid species, and the sour cherry (Prunus cerasus), a self-incompatible or self-compatible allotetraploid species derived from P. avium and Prunus fruticosa, share several S-RNase alleles, including S13. An inactive form, S13° ,i s found in some sour cherries. Two (AT) microsatellites are associated with allele S13-RNase, one in the first intron and one in the second. Their length polymorphisms were studied in 14 sweet and 17 wild cherries (both P. avium) and in 42 sour cherries. Fluorescent primers amplifying each microsatellite were designed and amplification prod- ucts sized on an automated sequencer. Variants ranged from 247 to 273 bp fo…