A comparison of dairy cattle systems in an irrigated perimeter and in a suburban region: case study from Morocco

Multivariate analyses were used to compare dairy production practices and their consequences on milk yield and profitability in cattle farms from two representative regions of Morocco. A regular follow-up of 118 farms (48 in the Rabat-Salé suburban belt and 70 in the Gharb irrigated perimeter) was undertaken to obtain accurate data. Results show significant differences between the two regions. Intensive milk production was more frequent in the suburban zone (more concentrates and better annual milk yield per cow). When conducting a “within-region” principal components analysis, farms’ discrimination appeared to take into account all management variables (feeding, cattle sales, profitability), with no reference to farms’ structural parameters (arable land and number of cattle). A typology of farms was then established using cluster analysis, with 4 distinct groups, namely: a) concentrates wasters, b) farms with a relatively important milk yield per cow, c) deficit dairy farms and d) beef oriented farms. The last group included almost exclusively farms from the irrigated perimeter (5 out of 7). These results indicate that dairy production promotion in Morocco requires more than just the intensification of forage production, but should focus also on improving management practices. The extension of complete and balanced dairy rations is urgently needed to enhance milk yield and profitability.     

Molecular epidemiological analysis of bat rabies viruses in Brazil

A molecular epidemiological analysis was performed in 19 rabies viruses (RVs) isolated from haematophagous, frugivorous and insectivorous bats, in Sao Paulo, Brazil. The authors carried out RT-PCR for amplification of the RV nucleoprotein (N) gene, and determined 1,335 nucleotide sequences of N gene by direct sequencing method. Phylogenetic analysis, which was based on the N gene of Brazilian RV isolates identified presently and previously, revealed that RVs isolated from bats were genetically divided into four lineages had a tendency to depend on the host bat species. The first lineage consisted mainly of haematophagous bat (Desmodus rotundus) isolates, including frugivorous bat (Artibeus spp.) isolates. Other three lineages consisted of insectivorous bat isolates; mainly Eptesicus spp., Molossus spp. and Nyctinomops spp. isolates, respectively. These results indicate a possibility of that there are bat species-specific RV variants in Brazil.     

Molluscicidal and anti-feedant activities of diterpenes from Euphorbia paralias L

Nine known diterpene polyesters of segetanes, jatrophenes and paralianes have been isolated from the aerial parts of Euphorbia paralias L. The molluscicidal activity of isolated compounds was evaluated on Biomphalaria alexandrina (Ehrenberg). Paraliane diterpene, (2S,3S,4R,5R,6R,8R,12S,13S,14R,15R)-5,8,14-triacetoxy-3-benzoyloxy-15- hydroxy-9-oxo-paraliane, was the most potent compound against the snail. Anti-feedant activity was tested by a conventional leaf disc method against third-instar larvae of Spodoptera littoralis (Boisd). Jatrophene diterpene, (2R,3R,4S,5R,7S,8R,13R,15R)-2,3,5,7,15-pentaacetoxy-8-angeloyloxy-14,15- dioxojatropha-6(17)-11E-diene, had the highest anti-feedant activity among the compounds tested.     

Genetics and molecular mapping of gynoecious (F) locus in cucumber (Cucumis sativus L.)

Gynoecious is an important economic trait of cucumber for determinant of earliness and yield, yet genetic mechanism is not well understood for this trait. The experiment was conducted using F₂ mapping population by crossing of PPC-2, a gynoecious and parthenocarpic line with Pusa Uday (monoecious and non-parthenocarpic cultivar). Out of 179 SSR markers screened, 39 markers differentiated the gynoecious and monoecious parents. However, only 17 markers were segregating with F₂ mapping population, those were used for genotyping and linkage map analysis and these markers were placed along with F locus on chromosome 6 covering a total distance of 100.4cM. The SSR markers, SSR13251 and UW020605 were found to be closely linked to gynoecious (F) locus at 1.0 and 4.5 cM, respectively. The segregation of F₂ population of PPC-2 × Pusa Uday and GPC-1 × Punjab Naveen and test crosses for sex type herein suggested that single dominant gene controlled the gynoecious sex expression in cucumber particularly in gynoecious genotypes PPC-2 and GPC-1. Therefore, the monogenic dominant nature of gynoecious sex identified in the present experiment and SSR markers closely linked to the F locus will be useful in marker-assisted backcross breeding for transfering gynoecious trait into horticulturally desirable varieties.     

Morphological attributes associated with early-season drought tolerance in spring durum wheat in a mediterranean environment

Impacts of drought during the reproductive development phase of wheat have been thoroughly investigated, while studies of the early-season drought effects are lacking. Field experiments were conducted to study the effect of duration of drought stress during the period from emergence to the end of tillering on the growth and performance of different wheat cultivars, and to identify traits that could be associated with the resistance to early season drought. Experiments were conducted on a Vertic Calcixerol soil in the semiarid cereal-growing region of Morocco in 1995 and 1996. Six spring durum wheat (Triticum durum Desf.) cultivars selected on the basis of variation in morphology, phenology, and zone of adaptation were subjected to four water regimes, including a well-irrigated control. The three water stress treatments were imposed by withholding water during the period from emergence to either the onset, middle, or the end of tillering. Subsequent irrigations provided adequate soil moisture for the remainder of the growing season. Results from both years were generally consistent. The differential responses of the six cultivars was mainly due to differences in numbers of kernels produced. High yields under early-season drought were attributed to high leaf area index under stress and, upon recovery, and to high tiller survival rate. The consistency observed over years in the relationships between grain yield and those traits that proved to be most associated with the resistance to early-season drought, would suggest the usefulness of these traits as selection criteria for breeding for improved drought resistance in a Mediterranean climate type of North Africa. This revised version was published online in July 2006 with corrections to the Cover Date.     

Differential Responses of Barley Landraces and Improved Barley Cultivars to Nitrogen-Phosphorus Fertilizer

Barley is traditionally grown in the Mediterranean region as a dryland crop, invariably under drought-stressed conditions and often without inputs such as fertilizer. Following research that demonstrated the benefits of fertilization, even under less-than-favourable rainfall condition, fertilizer use on cereals has increased dramatically in the past few decades in countries of West Asia-North Africa. With developments in breeding new barley cultivars for higher yield, combined with disease resistance and environmental adaptability, it is crucial to assess the extent to which such cultivars respond to fertilizer inputs as this may affect aspects of a breeding strategy, particularly the choice of germplasm for adaptation in any particular environment. Thus, we assessed the yield potential of 30 barley cultivars with a range of germplasm types, including new cultivars and landraces, in a greenhouse in two soil types with and without adequate nitrogen and phosphorus fertilizer, i.e., low and high fertility. By comparison with the unfertilized low fertility soils, the fertilizer treatment increased yield parameters by about 10-fold. However, the rankings of some cultivars changed markedly with fertilization; some increased, others showed poor responses and decreased relatively, and two performed well with and without fertilizer. Based on the differential responses at the initial screening stage in the greenhouse, it is possible to identify lines or cultivars that are highly responsive to fertilizers and to incorporate such germplasm for further development to produce high-yielding cultivars for commercial adoption by farmers.     

Experimental treatment ofBrucella melitensis infection in sheep with oxytetracycline alone or combined with streptomycin

The efficacy of oxytetracycline (OTC) alone or combined with streptomycin in the treatment of 118 Najdi ewes believed to have been naturally infected with Brucella melitensis, was evaluated by culture of selected tissues and organs at slaughter. Groups of sheep were given 250, 500 or 1,000 mg of OTC intraperitoneally (i/p) daily for six weeks and in the respective groups at necropsy 52, 69 and 100% of sheep were found to be Brucella-free. Treatment with 250 mg OTC (daily for six weeks i/p) combined with 1,000 mg streptomycin (daily for three weeks intramuscularly) increased the percentage of Brucella-free sheep to 82%. When a group of sheep were each inoculated i/p with 1,000 mg of long-acting OTC every three days over a period of six weeks, 75% of them were Brucella-free at necropsy. B. melitensis was isolated from all (24) non-treated (control) sheep. The results showed that long-term treatment with a high dose of OTC alone had succeeded in eliminating B. melitensis from a group of 16 naturally infected sheep.     

Antifungal activity of limonoids from Khaya ivorensis

Chemical investigation of the diethyl ether extract of the stem bark of Khaya ivorensis A Chev (Meliaceae) afforded ten limonoids of angolensates, ring D-opened limonoids and mexicanolides. The structures of the limonoids isolated were determined by comparison of their (1)H and (13)C NMR data with those reported in the literature. These compounds were evaluated for their antifungal activity against the plant pathogenic fungus Botrytis cinerea Pers. Methyl 6-hydroxyangolensate and 3,7-dideacetylkhivorin were also tested for their antifungal and antibacterial activities on several fungal and bacterial species. Methyl angolensate and 1,3,7-trideacetylkhivorin displayed the highest antifungal activity against B. cinerea, with respectively 62.8 and 64.0% mycelial growth inhibition at 1000 mg litre(-1), and 73.3 and 68.6% mycelial growth inhibition at 1500 mg litre(-1). 3,7-Dideacetylkhivorin showed stronger antifungal and antibacterial activities than methyl 6-hydroxyangolensate against all of the test fungi and bacteria except Penicillium expansum Link. This is the first report on the antifungal and antibacterial effects of these limonoids. Structure-antifungal activity relationships of the limonoids isolated are discussed.     

Development of resistance and cross-resistance in fenvalerate and deltamethrin selected strains of Spodoptera littoralis (Boisd.)

Resistances of 33- and 27-fold to the pyrethroids fenvalerate and deltamethrin, respectively, have been induced in larvae of the Egyptian cotton leafworm Spodoptera littoralis (Boisd.) by selection of two subcolonies of a field population in the laboratory. Selected strains showed relatively high levels of resistance (11- to 36-fold) to all the tested pyrethroids, moderate levels of cross-resistance (3- to 13-fold) to DDT and the carbamate aminocarb, and a slight increase in tolerance levels to endrin and lindane. The pyrethroid-resistant strains, by contrast, manifested no cross-resistance to the organophosphorus compounds that were tested. Moreover, a negative crossresistance was observed in the pyrethroid-resistant strains to dicrotophos, methamidophos and the carbamate methomyl.