EFFECT OF THE SUBSTRATE ON THE ROOTING OF ANNOTTE AIR-LAYERED BRANCHES

Annatto (Bixa orellana L.) has become of increasing importance because of the dyes, particularly bixin, produced in its seeds. Such dyes are of great advantage as compared to synthetic ones. Since asexual propa gation is more advantageous than sexual propagation it has stimulated the study of, methods of vegetative propagation in annatto plants, inc luding air layering. For the successfulness of this process, the subst rate is a determing factor. This work had as objective to study the ef fects, on the rooting of annatto air-layered branches, of substrates: red sand (S), day (C), wood dust (W) and combinations among them. Four teen plants were selected, each one representing a replication of the randomized block design utilized. The rooting of the air-layered branc hes was evaluated regarding rooting date and root number, fresh and dr y weight, and volume. The substrates S, B and 1/2S + 1/2C were the mos t effective, while the least effective were W and 1/2S + 1/2W. The oth er evaluated substrates were of intermediate efficiency. There were po sitive and significant correlations regarding leaf number and root num ber, leaf number and root fresh weight, leaf number and root dry weigh t, and leaf number and root volume.