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Tahıl Kist Nematodlarının buğdaya zararları
No full textBuğday (Triticum spp.) dünyada 216 milyon ha ekim alanı, 627 milyon ton üretimi ile tarımı yapılan kültür bitkileri içerisinde ilk sırada yer almakta ve insan beslenmesindeki öneminden dolayı birçok ülke için stratejik bir ürün olarak kabul edilmektedir. Türkiye, yaklaşık 9,4 milyon ha ekim alanı ve 19–21 milyon ton buğday üretimi ile dünyada önemli bir üretici ülke konumunda olup, buğday bitkisinin de aynı zamanda gen merkezi olarak bilinmektedir.
Buğdayda ürün kayıplarına neden olan pek çok biyotik ve abiyotik etmen bulunmaktadır. Bitki paraziti nematodlar, biyotik etmenler içerisinde yer alan önemli bir grubu oluşturmaktadır. Bitki paraziti nematodların dünya genelinde buğday üretiminde her yıl ortalama %7-10 oranında ürün kaybına neden oldukları bildirilmektedir. Dünyada buğdayda ürün kayıplarına neden olan bitki paraziti nematodlar; Tohum gal nematodu, Anguina tritici (Steinbuch, 1799), Soğan sak nematodu Ditylencus dipsaci (Kuhn, 1857) Kök-ur nematodları Meloidogyne spp., Kök lezyon nematodları Pratylenchus spp. ve Tahıl kist nematodu, Heterodera avenea group olduğu belirtilmektedir
Prevelance and population dynamics of Heterodera schachtii (Schmidt, 1871) in sugar beet and cabbage production areas of Niğde and screening of resistant cultivars
Get PDFFen Bilimleri Enstitüsü, Bitki Koruma Ana Bilim Dalı, Bitki Koruma Bilim DalıNiğde ilinde lahana (Brassica oleracea) ve şeker pancarı (Beta vulgaris var. saccharifera) üretimi yoğun olarak yapılmaktadır. Şeker pancarı kist nematodu (Heterodera schachtii) şeker pancarı ve lahana üretimini önemli ölçüde etkilemektedir. Bu tez çalışması, 2021-2023 yılları arasında Niğde ilinde lahana ve şeker pancarı ekim alanlarından yapılmış, şeker pancarından 104, lahanadan 100 toprak örneği alınmıştır. Örnekleme yapılan yetiştiricilik alanlarından elde edilen H. schachtii'ye ait kistleri morfolojik ve moleküler düzeyde teşhis edilmiştir. Örnekleme yapılan alanlar içerisinde kist yoğunluğu fazla olan iki tarlada popülasyon takibi yapılmıştır. Ayrıca kontrollü koşullarda, H. schachtii'nin bir dölündeki yaşam döngüsü araştırılmıştir. Lahanadan 10 çeşit, şeker pancarından 27 çeşit/genotip seçilerek çeşit reaksiyonları belirlenmiştir. Niğde ilinde örnekleme yapılan şeker pancarı ve lahana üretim alanlarının sırasıyla, %40 ve 41' nin H. schachtii ile bulaşık olduğu; söz konusu alanlarda ortalama kist yoğunluğunun sırasıyla 38 adet/250 gr toprak ve 146 adet/250 gr toprak olarak belirlenmiştir. Örnekleme yapılan alanlara ait her popülasyon için 12 numune seçilerek, ITS-rDNA ve COI-mtDNA gen bölgeleri çoğaltılarak elde edilen sekans dizilimlerinden tür teşhisleri yapılmış ve filogenetik ilişkisi belirlenmiştir. Örnekleme yapılan lahana ve şeker pancarı alanlarında H. schachtii'nin popülasyon takiplerinde, toprakta bulunan kist sayılarının en yüksek olduğu aylar Ekim ve Kasım en düşük olduğu aylar ise Mart ve Nisan ayları olarak belirlenmiştir. Toprakta bulunan 2. dönem juvenillerin (J2) sayılarının en yüksek olduğu ay Mart, en düşük olduğu ay ise Kasım ayı olarak gözlemlenmiştir. Popülasyon takibi esnasında alınan kistlerin her ay kesilerek içlerinde bulunan J2'lerin sayımı sonrasında J2 ve yumurta sayılarının en yüksek olduğu ay Kasım en düşük olduğu aylar ise Mart ve Nisan ayları olarak belirlenmiştir. Heterodera schachtii'nin yaşam döngüsünün belirlenmesi ile ilgili çalışmada, köke J2 olarak giren bireylerin üçüncü dönem de (J3) şişkinleşip kökü yararak çıkış yaptığı ve dördüncü döneme (J4) geçtiği görülmüştür. Konukçu reaksiyonu çalışmalarında, 10 lahana çeşidinde ve 27 şeker pancarın çeşidinde H. schachtii'ye karşı dayanıklılık gösteren herhangi bir çeşide rastlanılmamıştır. Lahana çeşitlerinden Sazlıca ve Balsarma çeşitlerinin H. schachtii'ye orta derecede tolerant olduğu bulunurken; diğer çeşitlerin ise yüksek derecede tolerant olduğu tespit edilmiştir. Şeker pancarı çeşit/genotipleri arasında, Vienetta ve ERÜ 180 yüksek tolerant, Regesta, ERÜ 250 ve ERÜ 148 orta tolerant, Turbata ve ERÜ 144 ise hassas çeşit/genotipler olarak değerlendirilirken; diğer yirmi çeşit yüksek derecede tolerant çeşit olarak belirlenmiştir. Çalışma sonucunda ilçede yoğun olarak tespit edilen H. schachtii'nin popülasyon yoğunluğunu azaltmak için, bölge çiftçisine ekim nöbeti ile tolerant çeşitlerin kullanılması gerektiği önerilmektedir.Niğde province is known to be a major producer of cabbage (Brassica oleracea) and sugar beet (Beta vulgaris var. saccharifera) in Türkiye and both crops are severely infested by the sugar beet cyst nematode (Heterodera schachtii). This study examined 104 soil samples from sugar beet and 100 soil samples from cabbage cultivation areas in Niğde province between 2021 and 2023. Cysts of H. schachtii collected from sampling sites were identified morphologically and molecularly and population fluctuation studies were conducted in two fields with high cyst nematode densities. Under controlled conditions, the life cycle of H. schachtii in one generation was followed. The susceptibility reaction of 10 cabbage varieties and 27 sugar beet varieties/genotypes to H. schachtii were screened. It was found that 40% and 41% of the sugar beet and cabbage production areas sampled in Niğde province were infected with H. schachtii, respectively. The average cyst densities in these areas were determined to be 38 cysts/250 g of soil and 146 cysts/250 g of soil, respectively. For each population from the sampled areas, 12 samples were selected and species identification was carried out based on amplification and sequencing of the ITS-rDNA and COI-mtDNA gene regions and their phylogenetic relationships were determined. The highest number of cysts in the soil samples was observed in October and November, while the lowest number was observed in March and April. The number of second-stage juveniles (J2) in the soil was highest in March and lowest in November. Cysts were cut open, and the number of J2s and eggs were recorded based on a monthly interval; monthly population tracking showed that the highest numbers were in November, while the lowest were in March and April. During the study of H. schachtii's life cycle was observed individual nematode juveniles enter the roots as J2s, exit the root as third-stage juveniles (J3), and then develop into the fourth-stage juveniles (J4). During the host-susceptibility reaction studies, there is no species among the 10 cabbage varieties and 27 sugar beet varieties/genotypes were found to be resistant to H. schachtii. While Sazlıca and Balsarma cabbage varieties were found to be moderately tolerant to H. schachtii, other varieties were determined to be highly tolerant. Among the sugar beet varieties/genotypes, Vienetta and ERÜ 180 were highly tolerant. While Regesta, ERÜ 250, and ERÜ 148 were found to be moderately tolerant and Turbata and ERÜ 144 were susceptible. The other twenty varieties were identified as highly tolerant. The study suggests that local farmers should use tolerant varieties and practice crop rotation to reduce the population density of H. schachtii, which is widely infested in the province
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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