Effect of Naphthalene acetic acid on thinning intensity, fruit qualitative and antioxidative characteristics of two peach cultivars

In order to determine the effects of Naphthalene acetic acid (NAA) on thinning intensive and fruit qualitative and anti-oxidant characteristics in two peach cultivars, an experiment was conducted in Research Station in Agriculture at the University of Tabriz in 2013 The experiment was arranged as factorial based on randomized complete block design in three replications in 'Anjiry maleki' and 'Kosary' cultivars. Treatments in four levels (0, 20, 40 and 60 ppm) after 14 days from full bloom when fruitlet diameter was 8-12 mm on selected branch was applied. Results showed that all treatments, caused effective thinning fruit in each two cultivars while in 'Kosary' cultivar abscission percentage was higher than 'Anjiry maleki'. All hormone concentrations were caused increasing length, diameter, vitamin C, pH, total solution soiled (TSS) in two cultivars. Amount of the fruit firmness was not significantly between control and hormone levels. For the both studied cultivars, the highest antioxidant activity belonged to NAA treatment in 40 mg/L concentration. Although, the NAA treatment in different concentrations had no significant effect on total phenol and flavonoid contents of fruit juice, it was improved fruit quality and thinning intensive in two peach cultivars.