PEACH BLOSSOM THINNING BY THE USE OF AMMONIUM THIOSULFATE

Peach thinning is a practice usually performed manually, so it requires a high demand of skilled hand labors, short period for realization and high cost.
This study aimed to investigate the use of ammonium thiosulfate (ATS), applied at blooming, as an alternative to hand thinning.
The experiment was conducted in a peach orchard, cultivar ‘Maciel’, on 13 year old trees, trained to vase and spaced 6 x 2 m.
The treatments consisted in hand thinning 40 days after full bloom (DAFB); treatments of ATS 0.5, 1.5 and 3% applied to 100% open flowers (OF) and of unthinned trees (control). The experimental design was randomized complete blocks, with five treatments in 4 replications and 2 trees per plot.
When the means were significant they were compared using Duncan’s Test.
Plants treated with ATS 0.5% did not differ from those used as control and resulted with heavy crop loads and smaller fruit diameter.
Trees treated with ATS 3% had overthinning effects showing very low fruit set, yield efficiency and total yield when compared to other treatments; however, trees produced the largest fruit diameter.
Trees treated with ATS 1.5% did not differ from those hand thinned; fruit showed similar diameter without decreasing the total yield.
Based on the results, applying ATS at 1.5% is an alternative to hand thinning.

VIII International Peach Symposium

M.A. Giovanaz, J.C. Fachinello, C.S. Door , C. Goulart

Prunus persica, chemical thinning, fruit set, crop load, fruit size

https://doi.org/10.17660/ActaHortic.2015.1084.49