Efficiency of methods applied for goat estrous synchronization in subtropical monsoonal climate zone of Southwest China

Two experiments were undertaken to select the efficient method applied for goat estrous synchronization. In experiment 1, a total of 120 does (Capra hircus) were divided into five groups with a randomized block design, and the does of treatment 1 were synchronized by intravaginal sponges impregnated with 30 mg Levonorgestrel inserted for 10 days. Does of treatments 2, 3, and 4 were treated with further injection of 25 IU follicle-stimulating hormone (FSH), 0.05 mg prostaglandin F2 alpha (PGF_2α), and 25 IU FSH + 0.05 mg PGF_2α at sponge withdrawal, respectively. The does in the control group (n = 40) without estrous synchronization treatment and natural estrous does were observed. In experiment 2, a total of 140 does in five goat farms in breeding and non-breeding seasons were treated with the selective efficient procedure. The results presented that all the employed treatments were capable of inducing and synchronizing estrous goats. According to estrous response and economy, the use of intravaginal sponges impregnated with 30 mg Levonorgestrel and 0.05 mg PGF_2α (treatment 3) is the first choice for estrous synchronization, and 95.0% of synchronized does demonstrated estrus, which was significantly higher than that of treatment 1 (P < 0.05) and control group (P < 0.01). The percentages of ovulating of treatments 3 and 4 were the same (95.0%), which were significantly higher than that of treatment 1 (P < 0.01). The ovulation rates among different groups were not significant (P > 0.05). When the selective procedure was applied to five goat farms, 85.7% (120/140) of does demonstrated estrus, and the kidding percentage, litter size, and prolificacy rate were 53.6%, 0.95, and 177%, respectively.     

Effects of additive iron on growth,tissue distribution,haematology and immunology of gilthead sea bream, <Emphasis Type="Italic">Sparus aurata</Emphasis>

The comparative effects of iron-supplemented levels on growth, tissue distribution, haematology and immunology of gilthead sea bream, Sparus aurata (2 g) were investigated, using four organic (50, 100, 200, 300 mg ORG/kg diet) and one inorganic iron source (200 INOR mg/kg diet). Fish were treated for 12 weeks with the experimental diets and maintained at a water temperature of 19–22°C. Growth (final weight and specific growth rate), tissue distribution (spleen, liver and muscle), haematological parameters (red blood cells, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration) and non-specific immune indexes (respiratory burst activity and antibacterial activity of serum) were analysed. No significant differences were found in growth and iron tissue distribution among the tested groups. Red blood cell counting was statistically higher in fish given 50 ORG, 100 ORG, 200 ORG and 200 INOR feeds. However, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration were not significantly affected by increasing dietary iron. Fish receiving the 100 ORG diet had the best performance with respect to the respiratory burst activity and significantly higher values for antibacterial activity of serum were obtained in fish fed with the 300 ORG diet. The present findings provided no clear evidence of the optimum iron concentration. However, there was adequate indication that iron supplementation enhanced the performance of gilthead sea bream, mainly from a haematological and immunological point of view.     

Molecular breeding for virus resistant potato plants

To engineer resistance against potato virus X (PVX), the viral coat protein (CP) gene has been introduced into two potato cultivars. Stable expression of the gene in transgenic clones throughout the growing season has been obtained and resulted in considerably increased virus resistance. With varying frequencies depending on the original cultivar used, true-to-type PVX resistant transgenic clones have been obtained. Since deviant light sprout characteristics were invariably associated with aberrations in plant phenotype, they can be used in procedures to early screen for deviations. Furthermore, it has been possible to unequivocally discriminate between the original untransformed and independent transgenic cultivars. Although no relation has been found between the presence, if any, of the CP of potato virus Y (PVY) or potato leafroll virus (PLRV) in CP gene transgenic potato, appreciable levels of resistance to these viruses has been obtained. This suggests that the mechanism by which a viral CP gene in the potato genome evokes resistance, differs amongst various viruses.     

Shifts in disease resistance induced by growth regulators

Experiments on the effect of various compounds with plant growth regulating activity led to the hypothesis that conditions inhibitory to indoleacetic acid (IAA) action or leading to a decrease in the IAA level in cucumber seedlings would be unfavourable for the development of cucumber scab, caused byCladosporium cucumerinum. Susceptibility decreased as the result of treatment with growth retardants, which cause an increase in IAA-oxidase activity in the plants, whereas application of indoleacetic acid or compounds expected to decrease the rate of oxidative breakdown of IAA in the seedlings resulted in an increase of susceptibility. Growing the plants under various periods of illumination also influenced both the susceptibility of the plants and the IAA-oxidase activity in the hypocotyl tissue.To obtain further information about the relation between the increase in resistance and the increase in the rate of IAA oxidation, the effect of one compound, viz. L-threo-β-phenylserine (abbr. phenylserine) was studied in more detail. The rate of oxidative breakdown of IAA was increased in extracts of hypocotyls and cotyledons of plants treated with phenylserine as compared with extracts of tissue of untreated plants. Extracts of phenylserine-treated plants were found to contain a higher cofactor and/or a lower inhibitor content than those of control plants. The substances involved were not identified, but this result may indicate a shift in the concentrations of various phenols in the tissue.The question must remain open whether a shift in the concentration of phenols some-how effected by phenylserine treatment determines both degree of susceptibility and rate of IAA oxidation independently, or whether the rate of IAA breakdown and the resulting change in IAA content in the plants is directly related to the degree of susceptibility.     

New potyvirus isolated from <Emphasis Type="Italic">Cryptotaenia japonica</Emphasis>

 A potyvirus, for which the name Japanese hornwort mosaic virus (JHMV) is proposed, was isolated from Japanese hornwort plants (Cryptotaenia japonica) with mosaic disease symptoms. The virus was used to inoculate mechanically 34 plants belonging to 33 species of 10 families. Of these species seven from two families were infected. Faint chlorotic spots appeared on the inoculated leaves of Chenopodium quinoa and C. amaranticolor, but no systemic infection occurred in these plants. JHMV systemically infected only Umbelliferae plants; they did not infect 26 other species in eight families. JHMV was transmitted in a nonpersistent manner by aphids (Myzus persicae). The virus was a flexuous rod-shaped particle about 750 nm in length. Sequencing the nucleotides in the 3′ terminal region of JHMV revealed that the coat protein contains 280 amino acids with a molecular mass of 32.2 kDa. The nucleotide sequence of the coat protein of JHMV had the highest similarity with that of Zantedeschia mosaic virus (83.3%) compared to those of other potyviruses (57.0%–64.9%). An antiserum against JHMV reacted strongly with JHMV and weakly with Potato virus Y. These results indicate that JHMV is a new potyvirus. Received: September 9, 2002 / Accepted: November 7, 2002 RID="*" ID="*" The nucleotide sequence determined in this work appears in the DDBJ/EMBL/GenBank nucleotide sequence databases with the accession number AB081518     

Note: Pyrethroid resistance and possible involvement of glutathione<Emphasis Type="Italic">S</Emphasis>-transferases in<Emphasis Type="Italic">Helicoverpa armigera</Emphasis> from Turkey

An introductory study was conducted to investigate the pyrethroid resistance ofHelicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) strains in Turkey, collected from cotton fields in the Adana and Antalya provinces, through two different synthetic pyrethroid insecticides: lambda-cyhalothrin and esfenvalerate. In addition, the roles of glutathioneS-transferases (GSTs) in this resistance mechanism were analyzed. It was found that whereas resistance ratios for lambda-cyhalothrin (LD₅₀ levels) were 3- and 98-fold increased in the Adana and Antalya strains, respectively, esfenvalerate ratios were 3.3- and 92.3-fold increased in the Adana and Antalya strains, respectively, with respect to the susceptible strain. Furthermore, Adana and Antalya strains showed 2.4- and 2.9-fold higher GST activities than the susceptible strain, respectively. In the Antalya field strain, the minor increase in GST activity compared with the resistance levels implies that GSTs may be not greatly involved in this resistance. It also provides evidence that they could not be the only metabolic mechanism responsible for resistance to lambda-cyhalothrin and esfenvalerate inH. armigera from Turkey. http://www.phytoparasitica.org posting Nov. 16, 2006.     

Critical Use Exemption for methyl bromide for soil disinfestation: Italy’s experience with the European union process

Methyl bromide (MB) was phased out on January 1, 2005, and a Critical Use Exemption (CUE) process has been established in order to define the rules for allocating the needed amounts of the fumigant. This paper deals with the effects of the CUE process on Italian horticulture. The actual usage of the amounts of MB allocated to Italy for the year 2005 in the different areas and on the economically most important crops was monitored and critically evaluated. The usage pattern monitored shows that already in the first year after MB phaseout, Italy was able to replace it completely on crops such as zucchini, salad greens, basil and watermelon. However, on crops such as tomato, pepper, melon, eggplant, strawberry, and cut flowers, further work is required in order fully to replace MB. The emerging problems and research needs are discussed briefly.     

Towards identifying pathogenic determinants of the chickpea pathogen <Emphasis Type="Italic">Ascochyta rabiei</Emphasis>

Ascochyta blight is a serious disease of cool-season grain legumes (chickpea, faba bean, lentil and pea) caused by fungal species of the anamorphic genus Ascochyta and related genera. Despite extensive studies on the biology, ecology, epidemiology and management of the disease, little is known about the pathogenic determinants of these pathogens. This research aims at using Ascochyta rabiei as a model for the genus in investigating genetic factors of pathogenicity, with the ultimate goal of elucidating pathogenic mechanisms. Three advances were made: (1) insertional mutants with altered pathogenicity were identified through in vivo screening, and genomic regions adjacent to the insertion sites in selected mutants were determined; (2) a phage library of A. rabiei genomic DNA was constructed, and the library was estimated to provide complete coverage of the A. rabiei genome. This library was used successfully to recover clones with DNA adjacent to insertional mutation sites and to isolate specific genes; (3) DNA probes specific for an acyl-CoA ligase (cps1) and a polyketide synthase gene (pks1) were developed and library clones containing the corresponding genomic regions were identified from the phage library. These advances provide the foundation and necessary tools for experimentation of ectopic complementation assays and targeted mutagenesis to elucidate the genetic mechanisms of pathogenicity of A. rabiei.