Effects of different doses of paclobutrazol and sucrose in the minimum in vitro growth of wild species of Manihot

Abstract

In vitro conservation, under minimal growth conditions, allows prolonging the periods between subcultures without affecting plant viability, besides reducing the contamination risk and the space required for cultivation. Experiments were conducted by using 8S as a basic culture medium, supplemented with combinations of five concentrations of paclobutrazol (PBZ - 0; 0.10; 0.20; 0.30 and 0.40 mg L-1) and sucrose (SUC - 0; 5; 10; 15; and 20 g L-1), resulting in 25 treatments, applied on three wild species: Manihot violaceae, M. flabellifolia and M. pseudoglaziovii. After 120 days of cultivation, the evaluated variables, namely plant height (cm) and the numbers of mini-cuttings with 1 cm, roots, shoots, green and senescent leaves, allowed verifying that, for the species M. pseudoglaziovii, the interaction of the 0.1 mg L-1 PBZ and 5 g L-1 SUC doses revealed a significant effect on the in vitro conservation. While for M. violacea, the combination of 10 g L-1 SUC and 0.2 mg L-1 PBZ is the most suitable for its conservation. Lastly, for M. flabelifolia, the concentrations used of SUC and PBZ did not prove efficient for in vitro conservation of the species.