Biodiversity and selection of "European" basil (Ocimum basilicum L.) types

Within the genus Ocimum, characterised by ample morphological and biochemical variation, sweet basil (Ocimum basilicum L.) has the highest economic importance, for its aromatic leaves and essential oil. This work reports the main outcomes of a five year research on the so called "European" sweet basil, that includes the two types traditionally used in Italy: "Genovese" and "Foglia di Lattuga". Preliminarily, sixty strains belonging to the two types were evaluated for essential oil content and composition. A robust discrimination of their main distinctive traits was obtained: "Genovese" showed higher essential oil and linalool content, with almost total absence of methyl chavicol, very abundant in "Foglia di Lattuga". In the following four years, about 200 progenies, derived from crossings of "Genovese" with "Foglia di Lattuga" and "Compatto", were chemically characterised. This research was carried out in support of the breeding program of a local seed company, aimed at obtaining new basil lines, combining the typical "Genovese" aroma, with increased leaf size and agronomic quality. Essential oil content varied between less than 3, in 2001, to more than 20 g kg(-1) d.m., in 2004. The most relevant components were linalool (16-62%), eugenol (4-40%), 1.8-cineol (1-17%) and methyl chavicol (0-37%). The mint note given by the latter is not appreciated in Italy; so its absence in the progenies was successfully pursued.