A new variety of Bacopa monnieri obtained by in vitro polyploidization

The commercial value of Bacopa monnieri, a widespread herbaceous plant in Argentina, can be substantially improved increasing its flower size by chromosome doubling with colchicine. MS supplemented with 0.25 mg/L of 6-benzylaminopurine proved to be an appropriate medium for the in vitro multiplication of nodal segments of B. monnieri. Polyploidization was achieved submerging nodal segments during 24 or 48 hrs in colchicine solution 0.001 and 0.01 percent P/V, in 1 percent DMSO. Segments submerged in water and in DMSO 1 percent aqueous solution were used as controls. DNA contents from recovered plants was measured and characterized and their phenotype described. Two tetraploid plants originated from independent events were detected. These plants showed significant differences in size and colour both in leaves and flowers compared to untreated controls.

Wild ornamental germplasm exploration and domestication based on biotechnological approaches: In vitro colchicine treatment to obtain a new cultivar of Scoparia montevidiensis

The genus Scoparia is native from Argentina. The diversity of colours and shape of their flowers bestows this genus a very interesting ornamental potential. The purpose of the present study is to explore the Scoparia species germplasm by means of in vitro polyploidization in order to improve their ornamental qualities. Accessions of S. montevidiensis var. montevidiensis, S. montevidiensis var. glandulifera, S. nudicaulis, S. hasleriana and S. dulcis were collected and maintained under greenhouse conditions. The Murashige-Skoog medium, supplemented with 0.25 mg/L BAP was used for the nodal segments multiplication of the five Scoparia species. Except for S. hasleriana, the multiplication rate of the other species ranged between 10 and 12 shoots per explant. The colchicine doses tested with S. montevidiensis were: 0.0; 0.1; 0.05; 0.01 and 0.001% (24 and 48 hrs). From a total of 364 recovered plants, 4 solid tetraploid and 16 chimeras were detected. Significant differences were observed for the size of flower, leaves, and the stem diameter among the tetraploid plants and between them and the control. The tissue culture proved to be a powerful tool both to multiply the Scoparia material incorporated to our germplasm collection and to obtain new improved varieties of this beautiful genus.