Synthetic seeds for in vitro preservation of Asparagus officinalis L.

Abstract

Abstract Background Asparagus (Asparagus officinalis) is a perennial vegetable of economic importance for its high nutritional and medicinal value. Male plants are more desirable because of their higher spear yield. Therefore, the aim of this study was to evaluate the efficiency of the gibberellin inhibitors; paclobutrazol (PBZ) and cycocel (CCC) for in vitro preservation by encapsulation of in vitro-derived shoot tips of the superior germplasm of the first generation of asparagus male hybrid; cultivar Mary Washington 500W. Methods An efficient technique for synthetic seeds production was achieved, consisting of 3% (w/v) Na-alginate dissolved in water, Murashige and Skoog (MS) medium, MS medium with the growth inhibitors; PBZ and CCC at different concentrations, and 0.1 M calcium chloride (CaCl2.2H2O). Synthetic seeds were stored at 4 ℃ and then cultured after different storage durations (0, 2, 4, 8, 12, 16, 20 and 24 weeks) on MS medium supplemented with 1 mg l−1 kinetin, 0.2 mg l−1 naphthalene acetic acid and 0.5 mg l−1 gibberellic acid for shoot tip multiplication; then, recovered shoots were transferred to MS medium supplemented with 1 mg l−1 indole butyric acid and 0.5 mg l−1 PBZ for rooting. Results The beads containing 1 mg l−1 PBZ considered the optimum for producing complete well-developed plantlets of Asparagus officinalis from recovered shoot tips after 24 weeks of storage that successfully acclimatized in the greenhouse. Conclusions This protocol is efficient for in vitro preservation by encapsulation of shoot tips and regeneration of Asparagus officinalis F1 male hybrid (Mary Washington 500w), using anti-gibberellin plant growth regulators within the beads to prolong the duration of storage and provide a continuous supply of the plant.