Biodiversidad y comportamiento agronómico en León de "Gentiana lutea" L. var. "aurantiaca"

Resumen

Gentiana lutea L., commonly known as yellow gentian, is distributed throughout the pastures and hillsides of Central and Southern Europe and Asia Minor. Its bitter compounds, mainly secoiridoid glycosides, localized mostly in the roots, give pharmaceutical qualities to the gentian roots. These qualities make the gentian roots suitable for traditional medicine as an appetite stimulant and for the treatment of different stomach problems. Also, the gentian roots are widely used in the manufacture of alcoholic and non-alcoholic bitter beverages. Due to its good properties, gentian root has been collected indiscriminately, being the wild populations over-exploited or even decimated. Because of that, gentian has been protected by law throughout Europe. G. lutea L. var. aurantiaca grows in the mountains of León, where wild populations are also threatened. It is an almost unknown cultivar, whose flowers range in colour from orange to almost red as compared to the yellow flowers of subspecies lutea. The starting point of this study resides in the importance of protecting gentian wild populations and, moreover, provide new economic activities in the northwestern mountain areas of the province of León. To carry out that, it is necessary to know more about the aurantiaca variety, the variability of wild populations, and to identify the best conditions for the multiplication and cultivation. For this purpose, 32 wild populations of the aurantiaca variety have been prospected, as well as 15 populations of subsp. Lutea from the Pyrenees and 4 subsp. of vardjanii in the Dolomites, which served as a control. ISSR molecular markers have revealed genetic differences between the aurantiaca variety and the other subspecies, reinforcing the identity of this variety. Also, these results showed evidence of genetic isolation of the populations and low genetic diversity within them, threatening the survival of these in a not distant future. The search for a suitable protocol to break seed dormancy, which combines high germination rates and high quality plants for the aurantiaca variety, by testing cold treatments and different doses of gibberellic acid, revealed that 100 mg/l of this hormone after and stratification period of three months at 4°C, achieves these goals. It was also detected a low germination capacity for those isolated populations which had expressed low variability in the ISSR molecular marker analysis. Four trials were established (for cultivation) in plots with different environmental characteristics, within and outside of the natural habitat of G. lutea L. var. aurantiaca. The results revealed that, it is possible to obtain more than 15 tons of fresh roots using sustainable cultivation in mountainous areas with acid soils and low slope. HPLC chromatography analysis of different gentian root samples showed that the concentrations of bitter compounds in the roots of G. lutea L. var. aurantiaca are comparable, or even higher, to those of subsp. lutea, and those concentrations in Vcultivated roots, mainly for amarogentine, are much higher than those obtained from wild plants, and even more when they are collected in spring. The knowledge of the variability of the studied populations, and the use of appropriate multiplication protocols, will enable to obtain high quality cultivated roots of G. lutea L. var. aurantiaca, both in yield and bitter compounds, making it a profitable and sustainable business. This cultivation will allow to recover the wild populations, while conserving biodiversity.