Yazar "Akyol, Nihat" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim
    Öğe
    Common ragweed: An emerging threat for sunflower production and human health in Turkey
    (Blackwell Publishing, 2016) Özaslan, Cumali; Önen, Hüseyin; Farooq, Shahid; Günal, Hikmet; Akyol, Nihat
    Common ragweed invasion poses serious risks to human health, biodiversity and agricultural production throughout the world. Although ragweed has an enormous potential to expand its range in Turkey, studies on ragweed have only concentrated on the Black Sea region. An exploratory survey was conducted to observe the level of ragweed occurrence on the nodes of predecided 10×10km grids in the Thrace region of Turkey. Ragweed populations were observed in 44 out of 129 sites in a wide range of habitats, including roadsides, pastures, agricultural fields and non-agricultural areas. The highest levels of ragweed infestation were recorded in the agricultural fields, followed by the roadsides. The most-invaded crop was sunflower. The sunflower fields had the highest ragweed coverage as well and invasion even resulted in crop failure alongside the field borders. A spatial analysis of the data indicated that ragweed exhibited an aggregated pattern over the Thrace region. Ragweed distribution was not associated with the characteristics of the soils, which had a varying range of pH, electrical conductivity and texture. The results revealed that ragweed invasion can arise as a serious weed problem, interfering with the sustainability of sunflower production in Thrace and other sunflower-producing regions of the country. A high degree of ragweed infestation also will contribute to the pollen level counts for the most crowded cities in the region, posing a serious danger to human health.
  • Küçük Resim
    Öğe
    Seed dormancy differences among common ragweed (Ambrosia artemisiifolia l.) populations distributed in different climatic regions of Turkey
    (University of Montenegro, 2020) Önen, Hüseyin; Akyol, Nihat; Farooq, Shahid; Özaslan, Cumali
    Common ragweed (Ambrosia artemisiifolia L.) is an allergenic invasive weed rapidly expanding its distribution range throughout Europe. Seed dormancy is among the most important seed adaptation traits, helping colonizing plants to avoid adverse environmental conditions. Furthermore, knowledge of seed dormancy enables to predict the seed germination timing of species and enforce specific management practices at suitable times. This study was aimed at determining the seed dormancy differences among different common ragweed populations distributed in two distinct regions of Turkey (i.e., eastern and western parts of the country). The seeds of all populations were extremely dormant (80.50-96.71% dormancy). The populations distributed in western part of the country were more dormant than eastern populations. Mechanical scarification and cold-wet stratification at 4°C for 2, 3 and 4 weeks were tested to infer their potential in releasing seed dormancy. Cold-wet stratification proved effective in releasing seed dormancy; however, populations differed in the stratification time required for seed dormancy release. Overall, eastern populations became non-dormant with lesser stratification time (i.e., 2 weeks), while western populations took longer stratification time to become completely non-dormant. Mechanical scarification with sandpaper also released seed dormancy and all populations behaved similar for this technique. This knowledge can be used to predict the germination timing of different populations distributed in two distinct regions of the country. Furthermore, the results can also be utilized in implementing effective management strategies at the proper time.