Ação de auxinas e cofatores fenólicos no enraizamento in vitro de variedades de cana-de-açúcar (Saccharum officinarum L.)

Abstract

This study evaluated the in vitro rooting of varieties of sugar cane RB92579-RB872552 and grown on MS medium supplemented with the auxin IAA (3-acetic acid) and IBA (indole-3-butyric acid). Established the following treatments: T0 - MS without auxin; T1 - 1.5 μmol L-1 IAA, T2 - 3.0 μmol L-1 IAA, T3 - 1.5 μmol L-1 IBA, T4 - 3.0 μmol L-1 IBA. The highest percentage of rooting (78.84%) of variety RB92579 was observed in plants of the T3, while for variety RB872552 the best result was obtained in T1 (82.5%). The varieties showed a higher rate of root initiation on the fifth day after inoculation, along with decrease of rooting. Treatments with IAA favored the formation of leaves and tillers in both varieties. The variety RB872552 the average number of leaves was higher than that of RB92579 throughout the experiment, regardless of the auxin treatment. Tillering was greater in variety RB92579 showed that 1.38, 1.60 and 1.87 tillers / plant at 10, 15 and 20 days respectively, while the variety RB 872552 had 0.96, 1.15 and 1, 32 tillers / plant in the same period. Tillering increased with time of treatment independent of the concentration and type of auxin used.