Zoran Keserović

University of Novi Sad, Serbia

Biserka Milić

Slavko Kevrešan

University of Novi Sad, Serbia

Nenad Magazin

Marko Dorić

University of Novi Sad, Serbia


NAA (α-naphthylacetic acid) thins apple fruits inconsistently regarding fruit set and weight and may cause small or misshapen fruits occurrence. Considering hormonal activity, surfactant properties and the impact of naphthenic acids (NAs) on the metabo-lism of auxins in plant tissue, it is assumed that thinning response and fruit size could be improved by adding NAs to NAA for chemical thinning of apple. The purpose of the re-search was to evaluate thinning efficacy of the mixture of NAA and NAs in two commer-cially grown apple cultivars, ‘Golden Delicious’ and ‘Fuji’, known to respond differently to the application of NAA. The following treatments were applied during a three-year pe-riod, from 2010 to 2012: 10 mg∙L-1 NAA, 10 mg∙L-1 NAA + 1.56 mg∙L-1 NAs, 20 mg∙L-1 NAA, 20 mg∙L-1 NAA + 3.12 mg∙L-1 NAs and an untreated control. The addition of NAs to NAA did not alter the effectiveness of NAA in reducing fruit set, while it significantly increased fruit weight compared to NAA applied alone in two of three years of the exper-iment. NAs modulated the effect of NAA on fruit weight of apple cultivar ‘Fuji’ by re-tarding fruit growth and causing a higher number of small fruits to occur compared to NAA applied alone.


α-naphthylacetic acid, fruit set, yield, fruit weight, fruit quality

Ansari, R., Naqvi, S.S.M., Khanzada, A.N. (1989). Effect of potassium naphthenate on auxin transport in Zea mays L. Pak. J. Bot., 21, 270–274.
Black, B.L., Bukovac, M.J, Stopar, M. (2000). Intraspur fruit competition and position influence fruit size at harvest and response to chemical thinning agents in spur-type ‘Delicious’ apple. Acta Hort., 527, 119–125.
Black, B.L., Bukovac, M.J., Hull, J. (1995a). Effect of spray volume and time of NAA application on fruit size and cropping of Redchief ‘Delicious’ apple. Sci. Hort., 64, 253–264.
Black, B.L., Petracek, P.D., Bukovac, M.J. (1995b). The effect of temperature on uptake of NAA by leaves of Redchief ‘Delicious’ apple. J. Am. Soc. Hortic. Sci., 120, 441–445.
Chitu, V., Chitu, E., Marin, F.C., Ionita, A.D., Cirjaliu-Murgea, M., Filipescu, L. (2010). Effects of foliar ecological products application on apple growth, yield and quality. Acta Hort., 868, 409–416.
Ćirin-Novta, V., Kuhajda, K., Kevrešan, S., Kandrač, J., Grbović, Lj., Rodić, P. (2004). Structural and physiological properties of natural petroleum acids from middle oil fractions of “Kelebija” oil. Acta Period. Technol., 35, 87–93.
Ćirin-Novta, V., Kuhajda, K., Kevrešan, S., Kandrač, J., Radić, Lj. (2002). Biological activity and structure of natural petroleum acids from lower fractions of “Velebit” oil. Acta Period. Technol., 33, 135–141.
Clemente, J.S., Fedorak, P.M. (2005). A review of the occurrence, analyses, toxicity, and biodegradation of naphthenic acids. Chemosphere, 60, 585–600.
Cristea, C., Campeanu, G., Ionita, A.D., Filipescu, L., Stefan, M. (2008). The biological responses to the advanced foliar fluidic nutrients applications. Rom. Biotech. Lett., 13, 3583–3589.
Frank, R.A., Kavanagh, R., Burnison, K.B., Arsenault, G., Headley, J.V., Peru, P.M., Van Der Kraak, G., Solomon, K.R. (2008). Toxicity assessment of collected fractions from an extracted naphthenic acid mixture. Chemosphere, 72, 1309–1314.
Jones, K.M., Koen, T.B., Bound, S.A., Oakford, M.J. (1991). Some reservations in thinning ‘Fuji’ apples with naphthalene acetic acid (NAA) and etephon. New. Zeal. J. Crop. Hort., 19, 225–228.
Kevrešan, S., Kovačević, B., Ćirin-Novta, V., Kuhajda, K., Kandrač, J., Pavlović, K., Grbović, Lj. (2007). Biochemical changes in cuttings of Robinia pseudoacacia after treatment with naphthenate. J. Serb. Chem. Soc., 72, 953–959.
Lochte, H.L., Litman, E.R. (1955). The petroleum acids and bases. Chemical Publishing Co., New York., pp. 368.
Loh, J.W.C. (1974). The stimulation of indoleacetic acid synthesis in bush bean plants (phaseolus vulgaris L.) by naphthenates. Plant Cell Phys., 15, 395–398.
Marini, R.P. (1996). Chemically thinning spur ‘Delicious’ apples with carbaryl, NAA and etephon at various stages of fruit development. HortTech., 6, 241–246.
Marini, R.P. (2002). Thinning ‘Golden Delicious’ and spur ‘Delicious’ with combinations of carbamates and NAA. HortSci., 37, 534–538.
Pavlović, K., Grbović, Lj., Vasiljević, B., Župunski, A., Putnik-Delić, M., Maksimović, I., Kev-rešan, S. (2015). The influence of naphthenic acids and their fractions onto cell membrane permeability. J. Serb. Chem. Soc., 80, 1–9.
Robinson, T.L. (2006). Inteaction of benzyladenine and naphtalneacetic acid on fruit set, fruit size and crop value of twelve apple cultivars. Acta Hort., 727, 283–290.
Siddiqui, S., Bangerth, F. (1995). Effect of pre-harvest application of calcium on flesh firmness and cell-wall composition of apples – influence of fruit size. J. Hort. Sci., 70, 263–269.
Stopar, M., (2002). Thinning of ‘Gala’ and ‘Golden Delicious’ apples with BA, NAA and their combinations. J. Cent. Eur. Agr., 3, 1–6.
Stover, E.W., Fargione, M.J., Risio, R.A., Yang, X., Robinson, T.L. (2001). Fruit weight, cropload, and return bloom of ‘Empire’ apple following thinning with 6-benzyladenine and NAA at several phenological stages. HortSci., 36, 1077–1081.
Thomas, K.V., Langford, K., Petersen, K., Smith, A.J., Tollefsen, K.E. (2009). Effect-directed identification of naphthenic acids as important in vitro xeno-estrogens and anti-androgens in north sea offshore produced water discharges. Environ. Sci. Technol., 43, 8066–8071.
Vaysse, P. (2002). Code amidon pomme, CTIFL.
Wertheim, S.J. (2000). Developments in the chemical thinning of apple and pear. Plant Growth Reg., 31, 85–100.
Williams, M.W. (1993). Comparison of NAA and carbaryl petal-fall sprays on fruit set of apples. HortTech., 3, 428–429.
Wort, D.J. (1976). Mechanism of plant growth stimulation by naphthenic acid. II Enzymes of CO2 fixation, CO2 compensation point, bean embryo respiration. Plant Physiol., 58, 82–86.
Wort, D.J., Patel, K.M. (1970). Response of plants to naphthenic and cycloalkanecarboxylic acids. Agron. J., 62, 644–646.
Wort, D.J., Severson, J.G., Peirson, D.R. (1973). Mechanism of plant growth Stimulation by naphthenic acid. Effects on nitrogen metabolism of Phaseolus vulgaris L. Plant Physiol., 52, 162–165.


Zoran Keserović 
University of Novi Sad, Serbia
Biserka Milić 
Slavko Kevrešan 
University of Novi Sad, Serbia
Nenad Magazin 
Marko Dorić 
University of Novi Sad, Serbia



Articles are made available under the conditions CC BY 4.0 (until 2020 under the conditions CC BY-NC-ND 4.0).
Submission of the paper implies that it has not been published previously, that it is not under consideration for publication elsewhere.

The author signs a statement of the originality of the work, the contribution of individuals, and source of funding.


Most read articles by the same author(s)