Response of superior seedless grapevines to a complex of some winter pruning treatments, two hydrogen cyanamide sprays and thinning of shoots and bunches

Abstract EN

In 2014 and 2015 years, mature Superior seedless grapevines were winter pruned on late Dec.

to have 11 fruit canes (FCs) each with 14 buds (11 x14) (control, prevailing in the region), 7 FCs each with 14 buds (7 x 14), 8 FCs each with 12 buds (8 x 12) and 10 FCs each with 10 buds (10 x 10).

All experimental vines were without renewal spurs.

Two hydrogen cyanamide (HC) (5%) sprays were applied on all experimental vines; the first spray was on 31 Dec.

on the basal sections of all FCs (buds 1-5), while the second HC spray was on 8 Jan.

on the whole FCs.

Control vines received only one spray on 8 Jan.

By mid-March, thinning of shoots and bunches was practiced to leave 60 shoots and 30 bunches on each vine.

The criteria of budburst, bud fertility, yield components, berry physical and chemical characteristics and vegetative growth were used to evaluate the tested treatments.

The obtained results revealed that budburst (%) was greatly enhanced on the basal sections of FCs (buds 1- 5), particularly with the shorter FCs.

Also, bud fertility was increased on the basal sections.

It could be recommended to winter prune Superior seedless grapevines to 10 FCs with 10 buds on each FC, and to spray HC (5%) twice, the first on the basal five buds on 31 Dec.

and the second on the whole FCs on 8 Jan.

and with shoot and bunch thinning by mid-March (60 shoots and 30 bunches/ vine).

This complex gave the highest yield, bunch and berry quality and vegetative growth.