No improvement in fruit quality through chemical flower thinning in sweet cherry (Prunus avium L.)

BACKGROUND: Chemical flower thinning with ammonium thiosulfate (ATS) was applied on branches of sweet cherry (Prunus avium L.) cultivars 'Blaze Star', 'Samba', 'Techlovan' and 'Merchant' (all grafted on GiSeIA S) in a two-year field study in 2006 and 2007. Different concentrations of ATS (8.82 and 17.64 g L(-1)) and different application times were studied. Fruit quality parameters analysed included crop load, fruit size, fruit weight, flesh/stone ratio, content of soluble solids, pH value and content of titratable acids. RESULTS: Crop load was significantly affected (P < 0.01) by application, cultivar and year. Fruit size, fruit weight and content of titratable acids were not improved by any of the application strategies. An influence of cultivar and application on pH value was observed (P < 0.05). Flesh/stone ratio was significantly enhanced (P < 0.05) in 'Blaze Star' only, while content of soluble solids was significantly affected in 'Techlovan' only in 2007. CONCLUSION: No general improvement in quality parameters was achieved by chemical flower thinning in the P. avium cultivars studied over a two-year field experiment. (C) 2009 Society of Chemical Industry