Breaking of dormancy in seeds and in vitro propagation of Cordia elaeagnoides A. DC.

Abstract

Cordia elaeagnoides A. DC. is a timber species of tropical deciduous forests, which from the difficulty of their seeds to germinate, the species has limitations to reproduce. In this context, a method was developed to break dormancy and asexually propagate it through axillary bud proliferation in vitro. The presence of healthy embryos in 1 100 lots of 1 seeds (100 seeds per lot) were evaluated; it was found that 39.45 % of them correspond to this condition. 260 ppm gibberellic acid were tested with 24, 48 and 72 immersion hours; the first one reached 96 % of germination. To establish in vitro propagation, embryo rescue was made in the Murashige and Skoog (MS) culture medium supplemented with 2 mg L-1 benzyladenine; 82 % germination was achieved. Seedlings were used for axillary bud proliferation, on which the MS and McCown’s media growth regulators 2-isopentiladenina, kinetin and benzyladenine at doses of 1, 2 and 3 mgL-1 were evaluated; an average of 3.03 shoots per explant was obtained in both kinetin and benzyladenine. For in vitro rooting 3-indole butyric acid at doses of 2.5 and 5 mg L-1 were used, plus adenine in darkness or photoperiod; data revealed that any 3-indole butyric acid dose induces rooting. It is concluded that for the germination of Cordia elaeagnoides seeds gibberellic acid should be applied to remove dormancy and for its asexual propagation in vitro, kinetin and benzyladenine in the proportions previously indicated must be used.