299 THE INFLUENCE OF PRE-HARVEST BORIC ACID APPLICATIONS ON THE ACCUMULATION OF SOME ANTIOXIDANT COMPONENTS IN ALPHONSE LAVALLÉE GRAPE CULTIVAR Zehra BABALIK 1 , Tunhan DEMİRCİ 2 , Özlem ARAS AŞCI 2 , Nilgün GÖKTÜRK BAYDAR 2 1 Suleyman Demirel University, Atabey Vocational School, 32670, Atabey-Isparta,Turkey 2 Suleyman Demirel University, Agricultural Faculty, Agricultural Biotechnology, 32260, Isparta-Turkey Corresponding author email: zehrababalik@sdu.edu.tr Abstract The aim of the research was carried out to determine the effects of boric acid (BA) applications on the accumulation of anthocyanins, β-carotene, ascorbic acid and total phenolics in ʻAlphonse Lavalléeʼ grape cultivar. BA was applied to vines with four different concentrations (250, 500, 750 and 1000 mg/L) and at two different periods (at blooming and at blooming+fruit set). At the end of the study, it was determined that the BA applications consist of 250mg/L and 750 mg/L of boric acid concentrations during both blooming and fruit set stages were the most effective applications providing the highest anthocyanins, β-carotene and total phenolics. On the other hand, boric acid applications had no important effects on the ascorbic acid contents in berries. Key words: ʻAlphonse Lavalléeʼ, antioxidant components, boric acid, pre-harvest applications. INTRODUCTION Antioxidants are substances that, at relatively low concentrations, acting to scavenge and stabilize of free radicals. The benefits of antioxidants are very important to good health. Antioxidants can protect the human body free radicals that may cause some chronic diseases including cancer, cardiovascular diseases and cataract (Shahidi, 2000; Pham-Huy et al., 2008). Consumers are becoming increasingly prefer aware antioxidant substances rich in fruits and vegetables because of their beneficial effects on health. Grape is one of the most important fruit commodities as widely grown through the world. Also, it is a significant source of nutritional antioxidants, such as polyphenols, anthocyanins as well as biologically active dietary components (Orak, 2007). Therefore, due to its rich phenolic compounds, such as antiradical and antioxidant properties, interest in grapes and grape products (especially food additives, pharmaceutical industry and natural cosmetic products) is increasing (Bourgaud et al., 2001; Ghafoor et al., 2009). To enhance the production of antioxidant substances, strategies such as treating with elicitors (UV, salicylic acid, methyl jasmonate, ozone) and invoking biotic and abiotic stresses have been used in both plant cell culture and intact plants (Dong et al., 2010; Krzyzanowska et al., 2012). However, optimizing the agricultural practices also provide a rapid and efficient way to increase the antioxidant content. Mineral nutrients are essential for the growth, survival and reproductive success of plants. Among the essential elements for healthy plants, boron (B) is responsible for activation of dehydrogenase enzymes, sugar translocation, nucleic acids, plant hormones and effect on cell wall structure cell elongation, root growth and transfer of sugar and altered production of a wide range of phenol content and metabolism. In addition to it is helpful in growth and productivity, fruit setting and yield. B deficiency has visual symptom on root and leaves growth, flower, cluster and berry development in grapevine. Severely reduced in internodes and shoot length, shoot tip death, low fruit set, and tiny berries are all common symptoms of B deficiency (Fleischer et al., 1998; Ruiz et al., 1998; Ebadive et al., 2001; Brown et al., 2002; Christensen et al., 2006; Singh et al., 2012). Several studies have demonstrated that B application increased the yield in grapes Scientifc Papers. Series B, Horticulture. Vol. LXII, 2018 Print ISSN 2285-5653, CD-ROM ISSN 2285-5661, Online ISSN 2286-1580, ISSN-L 2285-5653