In vitro multiplication and rooting of Echeveria pumila Lem. free of phytoplasmas

G. Arellano-Ostoa, S. Lagunas-Santiago, M.A. Alvarez-Ruíz, E.E. Villavicencio Gutiérrez, R.I. Rojas Martínez
The genus Echeveria (Crassulaceae), native from Mexico has great ornamental potential, Echeveria pumila presents commercial importance due to its phyllotaxis in spiral and obovate-cuneate leaves of blue-greenish or gray color, however some plants present symptoms of stem flattening (fasciation) and reduction of the size of the leaves, a characteristic of plants infected with phytoplasmas. The objective of this work was to design a protocol for in vitro multiplication and rooting of phytoplasmas-free Echeveria shoots. Sprouts generated from meristems of Echeveria pumila var. glauca, maintained in vitro for five years by successive subcultures in a Murashige and Skoog (MS) basal medium, were used. For multiplication, two concentrations of benzyl adenine (BA) (0.2 and 2 mg L‑1) were tested in combination with naphthalene acetic acid (NAA) (0.02 and 0.2 mg L‑1), respectively, in MS medium. Number of sprouts per explant and size obtained after 30 days during two successive subcultures was evaluated. In the rooting stage, sprouts with an average size of 2 cm were used. They were cultivated in a MS medium with 50% of its macro salts, enriched with 1 mg L‑1 of indol butyric acid (IBA) during 24 h and later transferred to a similar medium without hormones. Rooting kinetics, number and size of roots were evaluated after 30 days. Soil survival was evaluated 120 days after establishment in a mixture composed of tezontle and peat moss (2:1 v/v). The highest multiplication rate (13 shoots) was achieved in the medium with 2 mg L‑1 of BA plus 0.2 mg L‑1 of NAA. Roots were observed 7 days after the start of the process in 90% of the shoots with an average of 17 roots explant‑1 with a length of 6-15 mm. Survival was 94% with an average plant diameter of 3.5 cm with 24 leaves. Plants' sanity was verified through PCR.
Arellano-Ostoa, G., Lagunas-Santiago, S., Alvarez-Ruíz, M.A., Villavicencio Gutiérrez, E.E. and Rojas Martínez, R.I. (2020). In vitro multiplication and rooting of Echeveria pumila Lem. free of phytoplasmas. Acta Hortic. 1288, 193-198
DOI: 10.17660/ActaHortic.2020.1288.29
in vitro culture, growth regulators, Crassulaceae, micropropagation

Acta Horticulturae