A protocol for the micropropagation and in vitro polyploidization of an interspecific hybrid of Glandularia (G. peruviana x G. scrobiculata)

GONZÁLES ROCA, LUCÍA; IANNICELLI, JESICA; COVIELLA, MARÍA ANDREA; BUGALLO, VERÓNICA; BOLOGNA, PAULA; PITTA-ALVAREZ, SANDRA; ESCANDÓN, ALEJANDRO SALVIO

SCIENTIA HORTICULTURAE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 184 p. 46 - 54

0304-4238

The genus Glandularia (Verbenaceae) has more than 50 species and it holds great ornamental poten-tial due to its colorful flowers, long flowering period and low water requirements. Since the floriculturemarket avidly seeks novelties, increasing the diversity within the genus would increase its commercialvalue. Some of the traits that should be improved in these species are their architecture and the sizeand colors of the flowers and leaves. In this sense, obtaining polyploid individuals is an interesting strat-egy to achieve this objective. In this paper a hybrid of Glandularia peruviana × Glandularia scrobiculatawas cultured under in vitro conditions. Different plant growth regulators and their combinations weretested to obtain appropriate multiplication rates. The best results were obtained with the combination of6.6 M thidiazuron/0.03 M -naphthalenacetic acid, with a multiplication rate of 19 shoots per explant.The plantlets were first rooted and then acclimatized by transferal to an 8.0 cm diameter pot containingGrowing mix®, and maintenance inside a humidity chamber. For poliploydization, the explants wereexposed to colchicine in concentrations of 0.001% and 0.01% for 24 and 48 h. The 40 recovered plantswere characterized according to their DNA content. There were 21 diploids, 14 solid tetraploids, 1 solidoctoploid, 3 chimera tetraploids and 1 chimera octoploid. Phenotypically, the size of the flowers, inflo-rescences, pollen grains and stomata were significantly larger in polyploid individuals. Surprisingly, stemdiameter, leaf size and color intensity of the leaves and flowers were not significantly different betweendiploid and tetraploid individuals. Due to the size of the inflorescences, the tetraploid individuals are apromising starting material for a Glandularia breeding program.