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71.
The anthelmintic efficacy of ivermectin (IVM), piperazine citrate (PPZ) and fenbendazole (FBZ) alone, and combinations of FBZ with varying dosages of PPZ, was evaluated for the control of strongyles of Mangalarga equids. In all cases of positive strongly egg counts per gram of faeces (EPG) before and after treatment, pure populations of cyathostome larvae with eight gut cells were consistently observed in faecal cultures. The faecal egg count reductions (FECR) were evaluated between Day 7 and Day 56 post-treatment. Significant differences (P less than or equal to 0.05) were found between Day 7 and Day 49 when comparing the mean EPG values of IVM with those of the other anthelmintics. PPZ alone and the combination of FBZ (7.5 mg kg-1) and PPZ (55 mg base kg-1) did not show significant differences during the trial; both groups exhibiting an FECR of greater than 90% between Day 7 and Day 30. Horses treated with the combinations of FBZ (7.5 mg kg-1) and PPZ at either 40 or 25 mg base kg-1, and with FBZ alone at either 7.5 or 15 mg kg-1, showed an FECR of less than 90% 2 weeks after treatment. The emergence of a degree of resistance of strongyles to FBZ and PPZ in a segment of the cyathostomes in this population is suggested. 相似文献
72.
Trawling for cephalopods off the Portuguese coast—Fleet dynamics and landings composition 总被引:1,自引:0,他引:1
Tereza Fonseca Aida Campos Manuel Afonso-Dias Paulo Fonseca Joo Pereira 《Fisheries Research》2008,92(2-3):180-188
Fleet dynamics was addressed for three cephalopod taxa of commercial interest, the squid Loligo vulgaris, the octopuses Octopus vulgaris and Eledone cirrhosa, and the cuttlefish Sepia officinalis, for 48 trawlers of the fish trawling fleet. Landing profiles (LP) were identified based on the species composition of the landings using hierarchical cluster analysis. Four out of a total of 12 different LP were related to cephalopods and other species associated with them.The effects on the landing proportions of a number of variables, year, season and vessel, are analysed for each of the species studied using generalized linear models (GLM). The factor “vessel”, including an ensemble of technical characteristics as well as the abilities of individual skippers, explained most of the model deviance, strongly reinforcing the existence of a fleet component dedicated to catch cephalopods. However, time also explains much of the variation found in the data.Seasonal alternation between landings of octopodidae and cuttlefish was observed within a small group of old trawlers operating mainly off the south coast, following the abundance cycles of these species. For a larger group of more modern trawlers, operating off the western coast, inter-annual shift between octopus and squid was found, together with a well marked seasonal pattern between the catches of cephalopods and horse mackerel.Spatial patterns of activity were identified using vessel monitoring system (VMS) data available for trawlers in Portugal, demonstrating the existence of cephalopod targeting strategies in Portuguese fish trawling activities. 相似文献
73.
74.
75.
C. Fortes Ferreira M. Gonzaga Pereira A. da Silva dos Santos R. Rodrigues R.E. Bressan-Smith A. PioViana R. Figueiredo Daher 《Euphytica》2003,134(1):43-46
Among the main causes of poor yield in common beans are fungal, viral and bacterial diseases. Common bacterial blight, caused
by Xanthomonas axonopodis pv. phaseoli (Xap), is one of the major bacterial diseases leading to significant losses in Brazil. Chemical control is ineffective, therefore,
the use of resistant varieties becomes an interesting alternative. The objective of the present work was to evaluate disease
resistance under natural infection of the pathogen in 109 recombinant inbred lines (F7) of P. vulgaris originated from the cross HAB-52 (susceptible — snapbean) × BAC-6 (resistant — common bean) in two different environments,
as well as to calculate genetic parameters to assist in the selection of promising materials to be used in the CBB resistance
breeding program. The data of the genetic parameters were
compared to those calculated for the F3 generation originated from the same cross. The heritability results for DI (disease index) and VI (variation index) in F3 were 26.85% and 0.26, respectively, whereas in F7 they were 91.77% and 1.36, respectively. These results demonstrate a potential to be explored for this advanced population,
that in the future, along with other pathogen variability studies and tests in other environments, may provide more information
regarding a more precise evaluation of promising genotypes to be used in common bean breeding programs aiming to obtain CBB
resistant varieties.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
76.
M.A. Rodrigues A. Pereira J.E. Cabanas L. Dias J. Pires M. Arrobas 《European Journal of Agronomy》2006,25(4):328-335
The current increase in the organic agriculture segment has created a new market for fertilisers permitted for use in organic farming. Off-farm N sources for organic farming are scarce, considering the restriction on the use of chemical fertilisers. Thus, when some products are permitted in organic agriculture, commercial opportunities become available. In this study we compare the performances of Vegethumus (Veg) and Phenix (Phe), two manures that are permitted in organic farming, with several other manures, ammonium nitrate (AN) and control treatments. A 3-year field trial and a pot experiment were carried out in order to estimate dry matter yield, N uptake, and N nutritional status of the crops, as well as soil N availability, the latter was assessed by using anion exchange membranes inserted into the soil. Apparent N recovery (ANR) values in the field trial were 6.3% and 58.2% in Veg and AN plots, respectively, after the application of 380 kg N/ha in the previous five growing seasons. In the pot experiment, the ANR of Veg and Phe, the organic amendments permitted in organic farming, were 5.0% and 13.6%, while Beiraadubo (Bei) and Nutrisoil (Nut) had ANR of 27.2% and 42.0%. The poor results of the amendments permitted in organic farming, in light of their high prices suggest that their use must be carefully considered by farmer in their fertilization strategies. 相似文献
77.
78.
Luciana Rossini Pinto Maria Lucia Carneiro Vieira Cláudio Lopes de Souza Jr Anete Pereira de Souza 《Euphytica》2003,134(3):277-286
BR-105 and BR-106 are important tropical maize populations, which were submitted to a high-intensity reciprocal recurrent
selection, generating the IG-3 and IG-4synthetics. Using 30-microsatellite loci,we measured and compared the genetic diversity
of these populations and their synthetics. The populations did not differ significantly regarding the amount of genetic diversity.
As a consequence of selection, genetic variability losses, in terms of mean number of alleles per locus,proportion of polymorphic
loci, and gene diversity did occur and were greater in the synthetic IG-3 than IG-4. In the synthetics, the number of loci
in adherence to Hardy-Weinberg proportions was superior to that observed in the populations. The Wright's mean fixation index
was higher than the mean value expected for outcrossing species (5%) indicating as light excess of homozygotic individuals
in both populations. The genetic distances confirmed the favourable effects of one cycle of recurrent selection, as the synthetics
became more isolated in comparison to the original populations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
79.
Summary For RFLP mapping of R-genes, determining resistance to specific races of Phytophthora infestans in tetraploid potato, it is necessary to develop well segregating populations at the 2x level. During mapping studies, evidence was obtained that more genetic factor(s) are involved in the expression of R-genes than conventionally believed. Two experiments are described in which such an additional genetic factor was suppressing or enhancing the expression of unknown R
nand R
ifactors. R
nand R
iappeared to be present in the investigated plant material, containing R4 and R10, or in one of the susceptible crossing parents. In a third experiment, the expression and the segregation of the well known R1 gene was influenced by an additional genetic factor. In that case there were indications for a dominant suppressor. This was established by the selection of susceptible plants carrying a RFLP allele of probe GP21 closely linked to R1. In three of the four F1 populations, resulting from crosses between such susceptible plants and susceptible tester plants, resistnat progenies were found. The resistance appeared to be R1-specific. This clearly indicates that in three of the four investigated susceptible plants, the R1 gene was still present but not expressed. 相似文献
80.
Diego Villaseñor Renato de Mello Prado Gilmara Pereira da Silva Manuel Carrillo Wuellins Durango 《Journal of plant nutrition》2020,43(18):2785-2796
Abstract Foliar analysis is an effective method to diagnose the nutritional status of plants. However, the mineral concentration in foliar tissue has traditionally been evaluated by assessing the activity of each element, without considering the interactions between them. To address this, dual interactions were calculated using the Diagnosis and Recommendation Integrated System (DRIS) to identify which crop nutrients are most influential in nutrient imbalances and which are the most limiting nutrients for the nutritional status of banana crops in Ecuador. To achieve this, a regional survey of the nutritional status and its productivity levels was conducted for 188 different sites during the crop season in 2017–2018, involving banana cultivars ‘Vallery’ and ‘Williams’, from the Cavendish subgroup. The DRIS calculation method was combined with Beaufils and Jones functions. From the initial 188 foliar samples, 83 samples (representing 44% of the population) were considered to represent the high-yield reference population, with yields of 38–60 t ha?1. The DRIS method defined the mean nutritional balance index, which was not found to be statistically correlated (p?>?0.05) with productivity, revealing that there was no significant association with the nutritional status of the plants. Specific DRIS norms were obtained and indicated that deficiencies in K, N, Ca, and Fe, and excesses in Mn, B, Cl, Zn, S, Cu, and Mg were the most limiting nutrients for banana cultivars in the south of Ecuador. 相似文献