Influence of the Period of Peach Tree Chemical Thinning on Fruit Quality

The need to decrease production costs along with the lack of man power in the countryside has asked for cultural practices which lead to these factors, such as thinning. Thus, chemical thinning has been studied as an alternative to fruit manual thinning. Therefore, this study aimed at evaluating the quality of peach tree fruits after chemical thinning with metamitron at different time periods in the south of Brazil. The experiment was carried out in a commercial peach tree orchard with cultivars ‘Maciel’ in Morro Redondo, Rio Grande do Sul state, Brazil, from 2015 to 2016. Treatments consisted in the application of metamitron (doses of 200 mg L-1) on the 20th, 30th, 40th, 50th and 60th day after full bloom (DAFB) and manual thinning on the 40th DAFB. Epidermis color, pulp firmness, ripeness index, soluble solids, titratable acidity, juice pH, total phenolic compounds and antioxidant activity were evaluated. The application of metamitron in peach tree thinning did not affect peach color. Changes in the other variables related to the quality of fruits depended on the application period of metamitron in the thinning process and between crops.