Does plant growth and yield affected by Prohexadione Ca cause changes in chemical fruit composition of 'Loch Ness' and 'Triple Crown' blackberries?

Abstract

Two semi-erect blackberry cultivars, 'Loch Ness' and 'Triple Crown', were used to investigate the effect of Prohexadione-Ca (ProCa) on vegetative growth, generative potential and fruit quality parameters. ProCa reduced the cane and internode length, but increased the node number per meter of cane length in both cultivars. ProCa application enhanced the number of fruiting branches and yield per bush in the following year. Fruit weight, number of drupelets per fruit, fruit shape index, content of soluble solids, shikimic acid and some phenolics were significantly increased by ProCa. ProCa-cultivar interaction was significant regarding the content of quercetin-3-rutino-side and procyanidin trimer. 'Loch Ness' had approximately 40% higher yields per bush and contained abundant quantities of anthocyanins and flavonols, whereas larger fruits and higher content of primary metabolites, some flavanols and total hydroxycinnamic acid derivatives were found in 'Triple Crown'. According to obtained results, the ProCa application at the rate from 100 to 200 mg L-1 is able to establish acceptable growth control without negative effects on yield and chemical fruit composition.