FLOWER DIFFERENTIATION AND PLANT ARCHITECTURE OF RASPBERRY, BLACKBERRY AND WHITE- AND REDCURRANT

The research was aimed to describe the shoot growth, flower differentiation and flower bud positioning (architecture) of raspberry (primocane fruiting - ‘Erika’, ‘Dolomia’, ‘Lagorai’, ‘L03’ and floricane fruiting - ‘Tulameen’, ‘Violet’), blackberry (floricane fruiting - ‘Chester’, ‘Loch Ness’, ‘Tupì’) and currant (white, ‘Viktoria’, and red, ‘Junifer’, ‘Rovada’) during the growing season. One-year-old plants were planted and grown in Vigolo Vattaro (TN - northern Italy), 725 m a.s.l.; 46°0’0”N; 11°12’0”E. In the primocane fruiting raspberry cultivars, the flowers differentiated quickly in July while in the floricane fruiting cultivars the buds became reproductive in October. Notably, ‘Lagorai’ had an intermediate behaviour with a few buds differentiating in July and a high number in October. Blackberry cultivars ‘Chester’ and ‘Tupì’ showed a typical floricane behaviour, whereas ‘Loch Ness’ exhibited an intermediate differentiation type similar to the raspberry ‘Lagorai’. In currant, the flower differentiation started slowly, between June and July, reaching a maximum in September in cultivars ‘Viktoria’ and ‘Rovada’, while it began one month later in ‘Junifer’. The most interesting difference was related to the type of fruiting shoots: brachyblast, short or medium shoots showed high flower differentiation while long shoots differentiated flower buds in a very different way according to the cultivar.