The effect on polphenol oxidase activity of chemical and hand fruit thinning applications in some apple cultivars

In this study, MM 106 clone rootstock grafted on to Golden Delicious, Granny Smith and Red Chief apple cultivars were applied Naphthalene Acetic Acid (NAA) (5, 10 ppm) and Benzyladenine (BA) (100, 150 ppm) with hand and chemical thinning. Apple cultivars collected during harvest according to applications was determined polyphenol oxidase activity. According to the results of statistical analysis, the effect of application and variety x application interaction on polyphenol oxidase activity was found to be important (P<0.01). According to the results, polyphenol oxidase activity of Red Chief variety was higher in all applications compared to other varieties. As the NAA doses increased, while the activity of the polyphenol oxidase enzyme in the Golden Delicious and Red Chiefs increased, polyphenol oxidase activity decreased in Granny Smith variety. On the other hand, with the increase in the dose of BA, polyphenol oxidase activity was decreased in Golden Delicious and Red Chief, polyphenol oxidase activity increased in Granny Smith variety