Erwerbs-Obstbau, vol.61, no.3, pp.231-236, 2019 (SCI-Expanded, Scopus)
The aim of this study was to determine the effect of ammonium thiosulphate (ATS) and potassium thiosulphate (KTS) on crop load, fruit quality and fruit mineral content of the eight-year-old ‘Redchief’/M26 apple. Seven different treatments were performed in the study as ATS (1%, 2%, 3%), KTS (1%, 2%, 3%) and hand thinning (after June drop) except for unthinned control. Thinning treatments were carried out as single application in full bloom period. Hand thinning and 3% ATS treatments were the best practices to increase fruit quality (diameter, weight). The fruit set ratio among the applications varied between 13.20% (2% ATS) and 23.46% (1% ATS). Yield was lowest in 2% and 3% ATS. Thinning with ATS was found more effective compared to KTS. The lowest Fe, Cu and Zn elements were determined in 2% ATS application, and the difference between the applications in terms of other elements was found to be insignificant. Phytotoxic effect was not observed for any ATS or KTS doses. As a result, flower thinners can be used as an alternative to hand thinning to improve fruit quality in ‘Redchief’ variety.