Browsing by Author "Ozkan, Reyyan Yergin"

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Allelopathic Effect of Extract, Essential Oil and Hydrosol of Rosemary (Rosmarinus Officinalis L.) on Some Weeds and Culture Plant Seeds
(Parlar Scientific Publications (p S P), 2020) Kural, Leyla; Ozkan, Reyyan Yergin
This study was conducted between the years of 2017-2018 to determine the effect of rosemary (Rosmarinus officinalis L.) of which its allelochemical effect is known, on the germination of some weeds such as; redroot pigweed (Amaranthus retroflexus L.), lamb's quarters (Chenopodium album L.), black nightshade (Solanum nigrum L.), and corn (Zea mays L.) and sugar beet (Beta vulgaris L.). In the study, the methanol, aqueous extracts (15, 20, 25 %), essential oil (9, 18, 36 mu L/Petri dishes) and hydrosol (4, 8, 10 %) of the rosemary was used. It was determined that the seed germinations of all test plants were inhibited in significant amounts depending on the increase of concentration in all applications performed. The highest effect was obtained from the methanol extracts and it was determined they had that inhibited the germination of seeds of C. album and B. vulgaris at a ratio of 96 %. According to the results obtained, it is considered that the plant of rosemary to have herbicide effect will contribute to the use and development of biopreparations, which are sensitive to the human health and environment; and in addition, to the pest control of integrated weeds.
Allelopathic Potential of White Cabbage on Some Plants
(Czech Academy Agricultural Sciences, 2020) Kural, Leyla; Ozkan, Reyyan Yergin
The aim of this study carried out in 2017-2018 was to determine the effect of white cabbage (Brassica oleracea L.), which is known to have an allelopathic effect on the germination of some weed and cultural crops seeds. In addition to weeds, Amaranthus retroflexus L., Chenopodium album L. and Solanum nigrum L., cultural plants such as Zea mays L., Beta vulgaris L., were used in this study. It has been shown that the seed germination rate was decreased by the increased concentration of white cabbage post-harvest leaves extractions, which were made with different concentrations of aqueous and methanol extracts (30, 40, and 50%). The methanol extract was found to be more effective in germination. According to these results, S. nigrum and Z. mays seeds were less affected than A. retroflexus, C. album and B. vulgaris seeds. In the light of these data, it is observed that extracts obtained from white cabbage can be effective on some weeds; however, it was concluded that in order to reach more definite conclusions, studies on the subject should be increased, and similar studies should be continued under greenhouse or field conditions.
Changes of Weed Flora in Cereal Fields Over the Last 31 Years in Van, Turkey
(Pakistan Botanical Soc, 2020) Ozkan, Reyyan Yergin; Tepe, Isik
Agricultural activities carried out over time, and accordingly the developments in pest control methods, and climatic changes caused by the global warming affect the composition and density of weeds in agricultural areas. In order to determine and reveal the causes of this change, a survey was conducted on cereal fields in Van in 2017 and compared with the results of a 31 years old survey. A total of 71 weed species belonging to 23 plant families were identified in 2017, while 84 weed species belonging to 24 plant families were identified in 1986. Looking at the weed density in unit area, it was found that the weed averages were 41.8 in a square meter in 2017 and 82.8 in 1986. In both surveys, the number of weed species was almost equal to each other and the coefficient of Similarity Index (SI) for 2 surveys was calculated as 0.58 in terms of weeds. While the roughfruit corn bedstraw (Galium tricornutum Dandy.), tuberous cranesbill (Geranium tuberosum L.) and rye (Secale cereale L.) were detected as the most intensive species in 1986, the narrowleaf knotweed (Polygonum bellardii All.), goatgrass (Aegilops spp.) and summer pheasant's eye (Adonis aestivalis L.) were identified as the densest species in the recent study. When the weed distribution was assessed based on their abundances, the field bindweed (Convolvulus arvensis L.) with 21.3% frequency of occurrence and yellowweed (Boreava orientalisJaub. & Spach) with 19.5% frequency of occurrence were detected as the most common weeds in 2017. The field bindweed (Convolvulus arvensis L.) was the most common weed type in both studies, while the yellowweed was found to be common only in 2017. When both studies were compared, it was seen that the total weed density had decreased at a significant level during the last 31 years, although there had been significant increase in the density of several weeds, such as the yellowweed (Boreava orientalis Jaub. & Spach). It is considered that this decrease was due to the increase in cultivation and pest control techniques.
Control of Smoothseed Alfalfa Dodder (Cuscuta Approximata) in Alfalfa (Medicago Sativa)
(Friends Science Publ, 2017) Tepe, Isik; Celebi, Seyda Zorer; Kaya, Ilhan; Ozkan, Reyyan Yergin
This study aimed to determine the most appropriate control methods for smoothseed alfalfa dodder (Cuscuta approximata Bab.), infesting alfalfa (Medicago sativa L.) in Van, Turkey. The effects of imazethaphyr and imazamox herbicides and their application times, including three cutting heights of alfalfa, on controlling dodder were investigated. The study had a split-plot design with four replications, and the trial was conducted under field conditions from 2010 to 2013. The results indicated that pre-emergence applications of imazethaphyr, pre- and post-emergence applications of imazamox, suppressed dodder during the first year after application; however, the effect decreased in the following years. In 2013, a substantial decrease in the hay yield and raw protein ratio of alfalfa was found. In addition, the control of dodder was not significantly affected by different cutting heights. (C) 2017 Friends Science Publishers
Effect of Essential Oils and Hydrosols From Some Selected Lamiaceae Species on Redroot Pigweed (Amaranthus Retrollexus L.)
(Ars Docendi, 2021) Ozkan, Reyyan Yergin; Tuncturk, Murat
Allelopathy refers to chemical effect of a plant direct or indirect on germination, growth or development of neighboring plants. Allelopathy can be considered as a component of biological control that reduces the development of other plants. This study was carried out to determine the effect of Greek sage (Salvia fruticosa Miller), basil (Ocimum basilicum L.), Dragonhead (Dracocephalum moldavica L.), spearmint (Menta spicata L.), sage (Salvia officinalis L.), lemon balm (Melissa officinalis L.), oregano (Origanum onites L.) and thyme (Thymus kotschyanus Boiss.) on the germination of redroot pigweed (Amaranthus retroflexus L.) which causes significant yield loss in agricultural production. Essential oil (9, 18, 36 mu L/petri) and hydrosols (50, 75, 100%) of aromatic plants were applied to determine their inhibition effects on seed germination of A. retroflexus. The experimental design for in vitro was a randomized design with five replications. It has been shown that germination rate was decreasing by the increased concentration of essential oil and hydrosols of the tested plant species. Also, total germination inhibition of A. retroflexus depended on the essential oil doses; the rate ranged from-2.9 to 85%. Amongst the essential oils, the highest effect was observed in spearmint with 7% germination rate. It could be considered as an important solution, which would contribute in Integrated Weed Management of A. retroflexus by using different concentrations of essential oil and hydrosols from aromatic plants.