Çiğdem Sönmez

Chemical and genetic variability of selected Turkish oregano (Origanum onites L.) clones

Turkish oregano (Origanum onites L.) is a major aromatic plant that belongs to Labiatae family. In this work fourteen Turkish oregano clones have been characterized chemically and genetically. Essential oil obtained by hydro-distillation was characterized by gas chromatography. Genetic variation was determined by use of random amplified polymorphic DNA (RAPD) markers. Variation of essential oils in the selected clones was subjected to cluster analysis, and two chemotypes, carvacrol and thymol, were identified. Carvacrol was found to be the main component in all clones except clone-661, the main component of which was thymol. The oregano clones were divided into three main groups by clustering on the basis of RAPD markers. Genetic similarity values among the oregano clones ranged between 0.49 and 0.73 which was indicative of a low level of genetic variation. Clones originating from locations close to each other had similar RAPD markers. Correlation analysis of the genetic distance matrix and the Euclidian distance matrix revealed no significant correlation between them. The results also indicated that there is no relationship between genetic structure of the selected clones and essential oil composition.

Physiological and Biochemical Responses of Achillea Millefolium Group-Related Cultivar Proa to Different Nitrogen Regimes

ABSTRACT In the present study the effect of different nitrogen amounts (0 g [N0], 0.45 g [N1], 0.9 g [N2] and 1.35 g N [N3] per pot, corresponding to 0 kg·ha−1, 50 kg·ha−1, 100 kg·ha−1 and 150 kg·ha−1 N application in field conditions) and application times (at sowing, vegetative stage and pre-bloom stage) on the yield, relative water content, total nitrogen content and nitrogen use efficiency in plants of the Achillea millefolium group-related cv. Proa was investigated. Antioxidant activity, flavonoid content, rate and composition of the essential oils were also determined. Application of N2 increased the dry herbage and flos production, total nitrogen amount and nitrogen use efficiency, without affecting the essential oil rate while reducing the antioxidant activity. Higher amounts (N3] of nitrogen maintained the dry herbage and flos yield at levels similar to N2 but decreased the antioxidant activity and rate of the essential oil. The major component of the essential oil, chamazulene, was negatively (N1, N2) or not influenced (N3] by the nitrogen application, while variable changes were registered in the content of the other components. The data point to the nitrogen regime being a subtle tool for regulating the performance of cv. Proa plants.