BIOSTIMULANTS AND INDOLEBUTYRIC ACID IMPROVE ROOTING OF WOOD CUTTINGS FROM DIFFERENT GRAPEVINE ROOTSTOCKS

The rooting of rootstocks is considered a critical point in the production of high-quality grapevine planting material. To maximize the cutting rhizogenesis process, plant hormones, such as auxins, are used for the development of adventitious roots. In addition, some groups of biostimulant have as their main role the development of root system, ensuring good growth of the plant aerial part. However, research using algae extract-based biostimulants in vegetative propagation of vine rootstocks is scarce. In this sense, the objective of this work was to evaluate the use of the biostimulant based on algae extract and indolebutyric acid (IBA), in the development of the root system and vegetative growth of grapevine rootstocks. The rootstocks evaluated were '3309 C', '101-14 Mgt', 'Paulsen 1103', '99 R', '110 R', 'Kober 5BB', 'SO4', '420A Mgt', 'Solferino', 'Gravesac', 'IAC 572', 'IAC 766', 'IAC 313', 'Harmony', 'Freedom', 'Salt Creek' and 'VR 043-43'. The experimental design was completely randomized with four replications, arranged in a factorial scheme, involving 17 rootstocks associated with four treatments to stimulate rooting (IBA, algae extract, IBA + algae extract and control). The use of indolebutyric acid and algae extract-based biostimulant proved to be efficient in rooting woody cuttings from different vine rootstocks. The use of IBA, algae extract-based biostimulant and IBA combined with algae extract resulted in higher rates of rooting and development than the control. The rootstocks presenting the highest rooting rates and vegetative development were 'IAC 572' and 'Freedom'. 'Gravesac', '101-14 Mgt' and '99 R', showing high rates of rooting and root development, but low vegetative development. The rootstocks exhibiting the lowest rooting rates and vegetative development were 'Salt Creek', 'VR 043-43' and '110 R'.