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.

Environmental characteristics of the cemeteries of Buenos Aires City (Argentina) and infestation levels of Aedes aegypti (Diptera: Culicidae)

Cemeteries with many water-filled containers, flowers, sources of human blood, and shade are favorable urban habitats for the proliferation of Aedes aegypti, a vector of yellow fever and dengue. A total of 22,956 containers was examined in the five cemeteries of the city of Buenos Aires, Argentina. The vector was found in four cemeteries that showed an average infestation level of 5.5 percent (617 positive out of 11,196 water-filled containers). The four cemeteries positive for Ae. aegypti showed significantly different (p<0.01) infestation levels. Vegetation cover and percentage of infestation were significantly correlated (p<0.01), but neither cemetery area nor number of available containers were significantly related to the proportion of positive vases. Our results suggest that the cemeteries of Buenos Aires represent a gradient of habitat favorableness for this vector species, some of which may act as foci for its proliferation and dispersal