The yield, chemical composition, and antifungal properties of essential oils from six populations of Thymus zygis Loefl. ex L. were studied. Phytopathogenic fungi Pythium irregulare, Rhizoctonia solani, Colletotrichum acutatum, Fusarium oxysporum, and Sclerotinia sclerotiorum showed a clear inhibition in the poisoned food test. Inhibition is tested by EC50. This activity indicator ranges from 86 ppm in the most active oils to 577 ppm. Among the identified components of the oils, 3-octanol and α-terpinene had the highest correlation with the antifungal activity. Yield, antifungal activity, and plant morphology, led to the selection of the population T. zygis ssp. gracilis harvested at flowering stage as most suitable for potential agronomical use.

The variation in yield and essential oil composition of some plants of Thymus zygis was studied through their life cycle. The relationship between the concentration of the essential oils' main compounds and the most frequently used bioclimatic indices was stated. Individual samples from seven populations growing wild in the South Iberian Peninsula were studied to assess the phenological variation of their oils. The samples showed a maximum yield at the flowering stage. The most representative compounds were selected, statistically analyzed and clustered in two groups, called thymol and c-terpinene according to their behavior through the cycle of the plants studied.

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Conservation and utilization strategies require fundamental knowledge about levels of genetic diversity, population genetic structure and effective population size, because they are the key elements that determine a species ability to respond to selection, either natural and artificial procedures. Sweet chestnut (Castanea sativa Mill.), widely distributed around Europe, is a multipurpose tree species of great economic importance for fruit and timber. Moreover, chestnut contributes to carbon storage, the landscape structure and the biodiversity conservation, that are relevant factors for environment management especially under climate change. Although there is information about chestnut traditional varieties, up to now, there is not complete information on the genetic diversity of natural populations in Spain. In this study, patterns of genetic variation and structure are assessed within and among natural populations of chestnut in Spain. 17 natural populations were evaluated using 7 microsatellite markers and Alleles in Space (AIS) software. This study allowed to describe the level and distribution of the genetic variability in Spanish chestnut populations, showing a high genetic diversity. Moreover, populations displayed a structure that followed a geographical pattern, indicating in a first approach, a separation between populations from West and east of the Iberian Peninsula.