Characterization of <Emphasis Type="Italic">Bean common mosaic virus</Emphasis> and <Emphasis Type="Italic">Bean common mosaic necrosis virus</Emphasis> isolates in common bean growing areas in Turkey

Bean common mosaic virus (BCMV) and Bean common mosaic necrosis virus (BCMNV) are well-known legume-infecting potyviruses. The incidences of BCMV and BCMNV infections were determined by ELISA in 367 seed and leaf samples which were collected in 15 common bean-growing provinces of Turkey. Of the samples tested, 67 (18.2 %) occurred to be infected with BCMV, however only 5 (1.4 %) were infected with BCMNV. A total of 45 ELISA-positive samples were selected from single-virus infected ones to determine BCMV and BCMNV pathogenicity groups (PGs) by using a set of bean cultivars that contain different combinations of resistance genes. Some BCMV populations exhibiting unusual pathogenicity were identified. One of them, named TR-180, was found to overcome resistance conferred by bc-1, bc-1 ² , bc-2 and bc-2 ² recessive alleles in common bean and assigned to PG VII. This isolate shared high (99 %) sequence identity with previously identified BCMV RU-1 and RU-1-related strains (RU1-OR-B and RU1-OR-C) according to a BLAST analysis of the nucleotide sequences of RT-PCR amplified products comprising the complete coat protein and 3′ partial NIb regions. The isolates TR-203 and TR-256 produced a distinctive reaction pattern in the dominant I gene-bearing bean cultivars Amanda and Isabella at lower (<30 °C) temperatures and were classified into PG IVb. These isolates were found to be 99 % identical to US-1 strain based on 3′ terminal nucleotide sequences of the BCMV genome. A fourth isolate, TR-243, involved mixed BCMV populations, as confirmed by partial nucleotide sequence analysis; one was classified as belonging to PG VII being similar to TR-180, and another was assigned to PG IVb. In conclusion, on the basis of both the reactions of differential bean cultivars and ELISA results, most of BCMV isolates were assigned to pathogroup PG VII and BCMNV isolates to PG VIb. This study is the first to show that four recessive resistance alleles of common bean can be overcome by a single field isolate of BCMV, and that a wide range of BCMV pathogroups are present in Turkey.     

Spread of Tomato spotted wilt virus from an internal virus source by thrips species in Samsun, Turkey

The temporal and spatial distribution of Tomato spotted wilt virus (TSWV) was studied in a 2,085 m² tomato field with a total of 4,080 plants during 10 weeks from 5 July to 6 September in 2004. First infected plants were detected 4 weeks after the source plants were placed in the field and their number continued to increase by week 7. A total of 147 plants (3.6%) were recorded to be infected according to symptom occurrence and serological test by the end of the experiment. Thrips monitoring was carried out from May 25 to October 25 in the same year. Two thrips species, Frankliniella intonsa (Tryborn) and Thrips tabaci (Lindemann), were determined in the experimental area, with the latter one being the more prevalent (84.9%) species. There was a significant correlation (r?=?0.988, P?<?0.01) between the number of thrips species and the number of infected plants in the field. Majority of infected plants were not located near (0–10 m) an internal virus source within the experimental area, whereas 45.6% of the infected plants were located at a distance of 21–30 m. The number of infected plants at a distance of 21–25 m was significantly higher than at all other distances (P?<?0.05). There was no gradual increase in the distances of TSWV-infected plants within 0–30 m as time progressed. The virus seems to be transmitted by vectors through primary infections and scattered within 30-m distance, but limited secondary infections seem likely to occur after this distance in the case of a small internal virus source.     

Estimation of the effect of <Emphasis Type="Italic">Tomato spotted wilt virus</Emphasis> (TSWV) infection on some yield components of tomato

The effects of Tomato spotted wilt virus (TSWV) on yield and quality of tomato fruits were studied from May through November of 2004 at the Experimental Field of the Agricultural Faculty of Ondokuz Mayis University, in Samsun province, Turkey. TSWV caused 42.1% and 95.5% reduction in yield and marketable value of tomato, respectively. TSWV infection in tomato crop caused significant (P < 0.05) reductions in weight, total number, width and length of the fruits in infected plants. Reductions in yield-contributing parameters were 26.61% in weight, 20.18% in number, 10.94% in width and 11.93% in length of fruits. It is difficult to estimate the actual yield loss and influence levels of TSWV in the field. Economic data are scarce, but in the present study it was estimated that the yield loss due to TSWV in tomatoes was approximately $0.9 million in Samsun, Turkey.     

Fatty Acid Composition and Oxidative Stability of Fish Oil Products in Turkish Retail Market

The fatty acid composition and oxidative stability of fish oil and syrups available in the Turkish retail market were examined in this study. The major saturated fatty acids in capsules and syrups were palmitic acid (16:0) and stearic acid (18:0). The monounsaturated fatty acid contents of fish oil products have very different results (10.71–50.46%). The results show that the label claims for total omega-3, eicosapentaenoic acid, and docosahexaenoic acid presented a reasonable accuracy for the examined products, but it was noted that some of the results showed a considerable difference with the labels.

The free fatty acid level in fish oil products was generally low (0.13–1.95% of oleic acid). Peroxide value of all examined products was below the limit of 10 meq kg^?1 oils for edible oil as indicated in Codex (1999). It was detected that the p-Anisidine value of fish oil capsules (5.36–8.90) was considerably lower than for fish oil syrups (21.86–26.74). According to our results, the totox value of fish oil capsules evaluated in this study (7.08–17.35) was within acceptable limits. However, fish oil syrups (34.72–38.06) highly exceeded the upper tolerable limit (26).     

Occurrence of viruses in field-grown pepper crops and some of their reservoir weed hosts in Samsun, Turkey

Pepper production is affected by several viral diseases in Samsun, Turkey. To determine the identity of these viruses, a total of 313 samples from field-grown peppers were collected during surveys in 1998 and 1999, and tested by enzyme linked immunosorbent assay (ELISA). Six viruses,Alfalfa mosaic virus (AMV),Cucumber mosaic virus (CMV),Potato virus Y (PVY),Tomato mosaic virus (ToMV),Tobacco mosaic virus (TMV) andTomato spotted wilt virus (TSWV) were detected in the samples. Of 313 plants tested, 42 were doubly infected, and TMV+PVY (15.4%) was the most common double infection. This is also the first report of AMV in pepper fields in Turkey. The effect of some weed species that may act as reservoir of these viruses was also investigated in the region and of 24 weed species belonging to 15 families tested, 16 were found to be infected with at least one virus.Amaranthus retroflexus (Redroot pigweed) appeared to be a common host of CMV, PVY, ToMV, TMV and TSWV, whereasHibiscus trionum (Venice mallow) was recorded as a new weed host of PVY and TSWV. The majority of weed species found to be virus infected were very common in the pepper growing areas of the region. This indicates that pepper fields contaminated with these weeds are under risk of viral infections. http://www.phytoparasitica.org posting July 21, 2005.     

Distribution of resistance-breaking isolates of beet necrotic yellow vein virus differing in virulence in sugar beet fields in Turkey

Rhizomania, caused by Beet necrotic yellow vein virus (BNYVV), is one of the most devastating diseases on sugar beet throughout the world. A total of 235 BNYVV-infested soil samples taken from 29 provinces during the growing seasons of 2004–2005 and 2010–2011 were investigated for resistance-breaking properties of BNYVV isolates. BNYVV resistant (Rz1, Rz1?+?R2, Rz1?+?C48?+?minor genes) and susceptible (rz1) sugar beet cultivars were grown in the BNYVV-infested soils by the bait plant technique, and virus infection was evaluated based on disease symptom and DAS-ELISA. Of the soil samples tested, 57.4% produced infection in the roots of sugar beet cultivar (cv.) containing the Rz1 gene, 51.9% in cv. carrying the Rz1?+?Rz2 and 18.9% in cv. carrying the Rz1?+?C48?+?minor genes. Also, the presence of Beet soil-borne virus (BSBV) was evaluated by TAS-ELISA. Additionally, the presence of BNYVV RNA-5 component was investigated by RT–PCR using the primers specific for p26 coding region. Our results revealed that BNYVV isolates compromising resistance genes are highly common and widespread in sugar beet production areas in Turkey, and it seems unlikely that BSBV and/or RNA-5 were directly involved in RB-event.     

Sorption Studies of 2,4-D on Selected Soils

Adsorption/desorption characteristics of the herbicide 2,4-D on various types of soils were investigated. Batch equilibrium techniques were used in the laboratory experiments. Data were fitted to the linear and Freundlich sorption equations. K and Kf values ranged between 0.32–1.89 L- 1 mg and 2.6 × 10-3 – 7.4 mg kg- 1, respectively. Results showed that both for linear and Freundlich adsorption equations, for all soils, K and Kf were correlated to the organic matter content (r = 0.87 and r = 0.66, respectively). Adsorption was also positively correlated with silt and clay content of soils (r = 0.53) and negatively correlated with sand content.     

Changes of Fatty Acid Composition in Frog Legs (Rana esculenta) During Cold Storage Period: Irradiation Effect

This study investigates the changes in fatty acid profile of gamma irradiated frog legs (Rana esculenta) during cold (2°C) storage period. Instead of freezing the frog legs for a prolonged shelf life, gamma irradiated fresh frog legs can be used for consumer satisfaction, because consumers prefer fresh frog legs and are willing to pay more than for frozen in the European market. Frog legs were irradiated at doses of 0, 4, and 5 kGy using ⁶⁰Co sources. The main fatty acids of nonirradiated and irradiated frog legs (4 and 5 kGy) were palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1ω9), linoleic acid (C18:2ω6), and eicosatrienoic acid (C20: 3ω3, ETE). Low doses (4 and 5 kGy) of irradiation treatment had no effect on fatty acid components of frog legs compared to the nonirradiated ones (p > 0.05). The fatty acid composition of frog meat was characterized by its high linoleic acid content (17.1–21.4%). At the initial stage of the storage, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels of frog legs remained unchanged with low doses of irradiation (p < 0.05). These fatty acids decreased significantly in the irradiated group (p < 0.05) at the end of the storage period. However, there were no significant changes in nonirradiated frog legs after 10 days of storage.