Production of ‘Ponkan’ mandarin trees submitted to chemical thinning

Abstract

Information about the productive behavior and development of the mandarin fruit by the application of phytoregulators that promote thinning are essential in order to obtain fruit within the standards required by the market. This study was designed to test different Ethephon concentrations in ‘Ponkan’ mandarin tree grafted on ‘Rangpur’ lime tree, to evaluate the percentage of thinning, growth and fruit production within and below commercial patterns. Five concentrations of Ethephon were tested: 0, 200, 400, 600 and 800 mg L^-1, applied when the fruits were at the development stage of 25 to 30 mm in transverse diameter. A percent of 28.5 thinning was obtained in the plants treated with the highest concentration of Ethephon. The chemical thinning with Ethephon application did not affect the ‘Ponkan’ mandarin production within commercial standards and it reduced the number of fruits below the commercial standards. Due to the intense leaf abscission observed in plants treated with 800 mg L^-1 Ethephon concentration, the concentration of 600 mg L^-1 of Ethephon was considered the most suitable to promote ‘Ponkan’ mandarin thinning.