www.acta.media.pl Acta Sci. Pol. Hortorum Cultus, 18(3) 2019, 3–15 ISSN 1644-0692 e-ISSN 2545-1405 DOI: 10.24326/asphc.2019.3.1 ORIGINAL PAPER Accepted: 29.11.2018 ,  suleymankizil@gmail.com © Copyright by Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie , DETERMINATION OF SOME AGRONOMICAL CHARACTERISTICS AND ESSENTIAL OIL VARIATION IN DIFFERENT LOCAL Ocimum basilicum L. ECOTYPES UNDER SEMI-ARID CLIMATIC CONDITIONS Suleyman Kizil 1  , Ozlem Toncer 1 , Tahsin Sogut 1 , Emel Diraz 2 , Sengul Karaman 2 1 Department of Field Crops, Faculty of Agriculture, Dicle University, 21280 Diyarbakir, Turkey 2 Department of Biology, Faculty of Science and Leters, Kahramanmaras Sutcu Imam University, 46100 Kahramanmaras, Turkey ABSTRACT The study aimed to determine agronomic characteristics and essential oil components of diferent basil eco- types in semi-arid climatic conditions of South Eastern Anatolia, Diyarbakir, Turkey. Two-year harvest data about fresh and dry herb yield, dry leaf yield, essential oil content and its components from the plants of year 2015 and 2016 was analyzed in this study. Essential oil components were detected by gas chromatography/ mass spectrometry (GC/MS). The resulting outcomes demonstrated that both ecotypes and harvests had im- portant efects on fresh and dry herb, dry leaf yield and essential oil contents of sweet basil. The highest dry leaf yield was noted from green leafy ecotypes and from second harvest stage. Twenty-three constituents were detected in the essential oil of O. basilicum ecotypes. The main components of basil essential oil were linalool, methyl chavicol, neral, geranial and methyl cinnamate that difered according to ecotypes and har- vests during experimental years 2015 and 2016. Purple leafy basil ecotypes were determined as linalool rich, while greenish leaf ecotypes were abundant in methyl chavicol. Silbe – green ecotype contains higher neral and geranial levels than the other ecotypes. It was concluded that basil plant could be grown successfully and harvested two or more times to prefer for maximum dry leaf yield and essential oil contents under semi-arid climatic conditions. Key words: agronomy, basil, harvest stages, dry leaf yield, volatile oil, linalool INTRODUCTION Genus Ocimum (Lamiaceae) constitutes 30 species spread all over tropical and subtropical areas. They have high economic signifcance, the most developed and used species include O. americanum L., O. × citriodorum Vis., O. gratissimum L., O. basilicum L., O. tenuiforum L. and O. minimo L. [Labra et al. 2004, Da Costa et al. 2015]. Among these species, O. basili- cum L. is the most utilized and its popularity is based on the types of essential oils and their constituents that give a particular fragrance to the condiments. Albeit, it is generally utilized as therapeutic herb to treat kidney disorders, migraines, coughs, loose bow- els and worms [Simon et al. 1990, Patil et al. 2011]. Moreover, it is also a source of biologically dynam- ic and active constituents of fragrance and essential oils. These could also be used as nematocidal, anti- bacterial, and insect repellent compounds [Sagdic and Ozcan 2003, Patil et al. 2011]. Use of antioxidants