Reducing of citrus losses by spraying of synthetic auxins

ABSTRACT: Citrus with annual production more than 4.2 million tons in Iran, allocate the most horticultural crop production to itself. Significant and economic decreasing of fruit losses is a great help to producers, customers and national economy. In this experiment, effect of two synthetic auxins include naphthalene acetic acid (NAA) at 0, 300, 400 and 500 mg l-1 and 2,4-dichlorophenoxy acetic acid (2,4-D) at 0, 10, 30 and 60 mg l-1 concentrations was investigated on peel strength, pre harvest drop and different size frequency of Satsuma mandarin (Citrus unshiu) fruit. Spraying was performed in two separate randomize complete block design with 4 replications after ending summer physiological fruit drop (June drop). Results were shown that treatments 400 mg l-1 of NAA and 60 mg l-1 of 2,4-D, reduced pre harvest drop compare to control, significantly. All NAA and 2,4-D treatments decreased percent of small and very small fruit size and increase large and marketable fruit size, significantly. Based on results of this experiment, application of these auxins could be efficient in reduction of citrus fruit losses.