Tick removal

Ticks are blood feeding external parasites which can cause local and systemic complications to human body. A lot of tick-borne human diseases include Lyme disease and virus encephalitis, can be transmitted by a tick bite. Also secondary bacterial skin infection, reactive manifestations against tick allergens, and granuloma?s formation can be occurred. Tick paralysis is a relatively rare complication but it can be fatal. Except the general rules for tick bite prevention, any tick found should be immediately and completely removed alive. Furthermore, the tick removal technique should not allow or provoke the escape of infective body fluids through the tick into the wound site, and disclose any local complication. Many methods of tick removal (a lot of them are unsatisfactory and/or dangerous) have been reported in the literature, but there is very limited experimental evidence to support these methods. No technique will remove completely every tick. So, there is not an appropriate and absolutely effective and/or safe tick removal technique. Regardless of the used tick removal technique, clinicians should be aware of the clinical signs of ticktransmitted diseases, the public should be informed about the risks and the prevention of tick borne diseases, and persons who have undergone tick removal should be monitored up to 30 days for signs and symptoms

Performance of cotton F-1 hybrids and its relation to the mean yield of advanced bulk generations

The performance of intraspecific (Gossypium hirsutum) and interspecific (G. hirsutum x G. barbadense) F-1 cotton hybrids and its correlation with the mean yield of advanced bulk generations was assessed under Greek environmental conditions. For this, 14 intraspecific and five interspecific cotton F-1 hybrids were evaluated at two locations (Sindos and Vardates) during the 1985-88 period. In addition, two interspecific hybrids (5, 6), the three best (8, 7, 11) and two among the worst (4, 10) intraspecific F(1)s and their F-2 bulks were also evaluated at Sindos in 1986. This evaluation was repeated in the following years. In each successive year the new generation (up to the F-5 bulk) was included. Intraspecific F-1 hybrids outyielded the best variety at both locations. Lint yield of the F-1 hybrids ranged from 99 to 158% with a mean value of 122%. Useful F-1 heterosis (hybrids with higher values than the best check cultivar) was also expressed for boil weight and Verticillium wilt infestation. The latter was more pronounced in hybrids derived from tolerant parents. All F-1 interspecific hybrids were dominated by the barbadense phenotype and had its superior fiber lint quality, lower lint percentage, and resistance to Verticillium wilt. In addition, they expressed positive heterosis for lint yield at Sindos and negative at Vardates, compared with the check variety. The frequency of the hirsutum phenotype progressively increased in the F-2 through F-5 generations, with plant height, bell weight, earliness, fiber quality and wilt tolerance moving toward the hirsutum values. In the F-2 generation yield dropped dramatically (> 50%) in the interspecific hybrids, whereas in the intraspecific hybrids inbreeding depression was much less and varied from hybrid to hybrid. The good F(1)s intraspecific hybrids maintained part of their useful heterosis in the F-2. From the F-3 onwards the yield improved in the interspecific crosses and stabilized around 75% of the yield recorded in the best check variety. In contrast, the highest yielding F-1 intraspecific hybrids yielded progressively less in subsequent generations, and in the F-5 they produced the same yield as the best cultivar, whereas the yield of the lowest yielding intraspecific hybrids was stabilized around 95% of the yield recorded in the best cultivar. It was concluded that yield of the F-1 did not predict the yield of the bulks in the following generations. Yet, the combined performance of the hybrids in the F-1 and F-2 generation could be a good indicator to identify the most promising populations to be utilized either as F-2 hybrids or as a source population for further selection. (C) 1999 Elsevier Science B.V. All rights reserved

Comunicación corta. Efecto de la densidad de la plantación en la variabilidad planta a planta del rendimiento expresado como coeficiente de variación en cebada

The effect of plant density on the coefficient of variation (CV) for individual plant yield was studied in barley (Hordeum vulgare L.). An F2 population originating from the cross Niki x Carina was planted in three densities: high (51.32 plants/square m), intermediate (4.61 plants/square m), and low (1.15 plants/square m) using the honeycomb design. In each of the experiments, the most promising 15 plants were selected based on the individual plant yield. Progeny (F3) of the 30 plants selected from the intermediate and the low plant density were grown the following year in two experiments under an intermediate and low density. It was observed that in the F2 population the CV was reduced from 71 to 55% when the density reduced from 51.32 to 4.61 plants/square m, whereas the CV value was increased when the density was further reduced to 1.15 plants/square m. Similarly, the following year the CV was increased from 39 to 56% when the density was decreased from 4.61 to 1.15 plants/square m in the F3 generation, and from 22 to 58% in the control. It was concluded that for barley an optimum plant density might exist under which the CV for individual plant yield is minimized and therefore the effectiveness of selection might be optimized.Se estudió en cebada (Hordeum vulgare L.) el efecto de la densidad de plantación en el coeficiente de variación (CV) del rendimiento individual de la planta. Se plantó una población F2 originada desde el cruce Niki x Carina en tres densidades: alta (51,32 plantas/m cuadrado), intermedia (4,61 plantas/m cuadrado), y baja (1,15 plantas/m cuadrado) utilizando un diseño en colmena. En cada uno de los experimentos se seleccionaron las 15 plantas con mayor potencial según el criterio de rendimiento de planta individual. La descendencia (F3) de las 30 plantas seleccionadas de zonas de densidades baja e intermedia se cultivó el año siguiente en dos experimentos en condiciones de densidad intermedia y baja. Se observó que en la población F2 el CV se redujo desde 71 al 55% cuando la densidad bajó de 51,32 a 4,61 plantas/m cuadrado, mientras que el valor del CV aumentó cuando se redujo aún más la densidad, a 1,15 plantas/m cuadrado. De forma similar, el año siguiente el CV aumentó de 39 a 56% cuando la densidad bajó de 4,61 a 1,15 plantas/m cuadrado en la generación F3 y de 22 a 58% en el control. Se concluye que, para cebada, podría existir una densidad de plantación óptima bajo la cual el CV del rendimiento individual se minimiza y, por tanto, la efectividad de la selección se puede también optimizar

Comparative efficiency of honeycomb and conventional pedigree methods of selection for yield and fiber quality in cotton (Gossypium spp.)

The effectiveness of honeycomb pedigree selection (HPS) as compared to conventional pedigree selection (CPS) was studied in one intraspecific (G. hirsutum L. x G. hirsutum L.) cross population (population I) and one interspecific ( G. hirsutum L. x G.barbadense L.) cross population (population II). Combined selection for yield and lint quality traits was applied for four cycles at two locations for population I and at one location for population II. Finally, the best F-6 lines derived by each method, together with the unselected population derived by single seed descent (SSD) and three check cultivars, were tested in comparative experiments, separately for each cross, at the same locations. In both populations the analysis of variance indicated significant differences among the groups of the material tested for seedcotton yield, mean boll weight, micronaire reading, staple length, and uniformity ratio. No significant differences were found with respect to plant height, lint percentage, and fiber strength in population I and with respect to lint percentage and fiber strength in population II. In population I, on the basis of mean seedcotton yield and number of superior lines derived by each method as compared to the check varieties and the unselected SSD population, HPS-lines were superior to CPS-lines for seedcotton yield, fiber length and boll weight. HPS-lines, however, did not differ significantly in seedcotton yield from the best check cultivar Eva. Finally, the material derived by CPS was earlier in maturity than the material derived by HPS and SSD. Also in population II, on the basis of mean seedcotton yield and number of superior lines derived by each method as compared to the unselected SSD population, HPS-lines were superior to CPS-lines. No significant differences, however, were identified between the material of the two methods for lint quality traits. It was concluded that in both populations HPS was more effective than CPS in identifying lines with high yielding ability and good lint quality. This superiority of HPS is attributed, at least partially, to its effectiveness in early generation selection

Evaluation of faba beans for resistance to sclerotinia stem rot caused by Sclerotinia trifoliorum

Sclerotinia stem rot, a fungal disease caused by Sclerotinia trifoliorum, is often a serious problem in faba beans (Vicia faba). The levels of resistance to sclerotinia stem rot were evaluated in 23 faba bean cultivars originating from various European countries, 18 cultivars from ICARDA, five cultivars from Canada, 58 populations originating from various provinces of Greece, and five V. narbonensis populations. Evaluation was done under controlled conditions following artificial inoculation with carrot root pieces colonized by the fungus. Faba bean plants were scored for resistance on a 0 to 3 severity scale. There was significant variability for resistance to S. trifoliorum among faba bean cultivars and among populations. Seven cultivars and 15 Greek faba bean populations showed a satisfactory level of resistance (≤ 1.50), whereas 22 cultivars and 25 populations were susceptible (> 2.00). However, all V. narbonensis populations were resistant to S. trifoliorum (disease severity from 1.11 to 1.44) without significant variability within populations. Variability in the resistance of faba beans to S. trifoliorum would allow selection within appropriate genotypes for breeding in an effort to provide an effective alternative for sclerotinia stem rot management in this crop.La pourriture à sclérotes, une maladie fongique causée par le Sclerotinia trifoliorum est souvent un grave problème pour la production de féverole (Vicia faba). À la suite d’une inoculation artificielle avec des morceaux de carottes colonisés par le champignon, l’intensité de la résistance à la pourriture à sclérotes a été évaluée en conditions contrôlées chez 23 cultivars de féverole provenant de divers pays européens, 18 cultivars de l’ICARDA, cinq cultivars canadiens, 58 populations issues de diverses provinces de Grèce et cinq populations de V. narbonensis. Une cote de résistance a été attribuée à chaque plante sur une échelle d’intensité de maladie allant de 0 à 3. Il y avait des différences significatives pour la résistance au S. trifoliorum parmi les cultivars et parmi les populations de féverole. Sept cultivars et 15 populations grecques de féverole ont démontré un degré satisfaisant de résistance (≤ 1,50), alors que 22 cultivars et 25 populations étaient sensibles (> 2,00). Par contre, toutes les populations de V. narbonensis ont été résistantes au S. trifoliorum (intensité de maladie entre 1,11 et 1,44) sans qu’il n’y ait de différence significative entre les populations. Les différences de résistance au S. trifoliorum dans la féverole signifient qu’il serait possible de procéder à de la sélection au sein de génotypes choisis afin d’offrir l’amélioration génétique comme moyen efficace de lutte contre la pourriture à sclérotes de cette culture

Prediction criteria of promising F-3 populations in durum wheat: A comparative study

Effective selection of parental material and promising segregating populations is an essential requirement for breeding success. There are many contradictive reports about the best parent selection criterion for the development of promising crosses. For the clarification of this problem field experiments were conducted for four consecutive years to compare the effectiveness of six criteria for the prediction of the most promising F-3 populations in durum wheat (Triticum durum L.): the mid-parent value, the F-1, the F-2, the (F-1 + F-2)/2, and the genetic distance among the parents as it is calculated using the SSR and RAPD molecular markers. During the first growing season (2003-2004) nine commercial cultivars of durum wheat and four landraces were crossed. The following growing season (2004-2005), 17 crosses (F-1 generation) were evaluated under low plant density (1.15 plants m(-2)) in a replicated (R-21) honeycomb design. During the third growing season (2005-2006), the four highest yielding crosses, one cross with an intermediate yield, and the three crosses with the lowest yield (172 generation) were evaluated under low plant density in a R-9 honeycomb design. Finally, in the fourth growing season (2006-2007) progeny of the aforementioned eight crosses (173 generation) and the ten parents were evaluated in a randomized complete block design in two locations. Furthermore, the genetic distance among the parents was determined using the SSR and RAPD molecular markers. It was observed that the three F-3 populations with the lowest yielding ability were the ones with the lowest mid-parental value. In addition, one of the two top F-3 populations was second in the rank according to the mid-parental value. Furthermore, the two top F-3 populations were also the highest yielding in the F-1 and F-2 generations. On the contrary, none of these crosses were predicted by the genetic distance as it was calculated using the SSR and RAPID molecular markers. It was concluded that parental pairs with high mid-parental value and high combined yield (F-1 + F-2)/2 obtained after evaluation of their F-1 and F-2 at low plant density was the most effective way to predict promising F3 populations. (C) 2008 Elsevier B.V. All rights reserved