Stefanos Kostas

Olive (Olea europaea L.) is a crop of enormous economic and cultural importance. Over the years, the worldwide production of olive oil has been decreasing due to various biotic and abiotic factors. The current drop in olive oil production resulting from climate change raises concerns regarding the fulfillment of our daily demand for olive oil and has led to a significant increase in market prices. In the future, there will be a higher chance that we will face a severe shortage of olive oil, which could harm both the economic sector and the food supply. As olive groves cover more than 5 million hectares in the European Union alone, the need to preserve the crop in the context of extreme climatic events is imperative. As drought is considered one of the most limiting factors in agriculture, drought-resistant varieties and sustainable irrigation strategies are being developed to mitigate the impact of drought on crop productivity and secure the future supply of olive oil. This review focuses on recently gained insights into drought stress in olive trees through omics and phenomics approaches to unravelling mechanisms that may lead to developing new varieties that are tolerant against drought elicited by changes in growing systems.

Gardenia jasminoides Ellis is an evergreen shrub with white fragrant flowers, and it is cultivated for its ornamental, aromatic and medicinal value. The present study aimed to select desirable genotypes for potential commercial exploitation as pot plants or use in perfumery. Thus, 32 genotypes of G. jasminoides plants derived from seedlings, whose seeds were obtained from Australia and the USA, were evaluated for their genetic diversity in relation to four commercial cultivars (‘Pelion’, ‘Joy’, ‘Grandiflora’ and ‘Kimberly’, used as reference cultivars) using ISSR and SCoT markers. A cluster analysis separated the gardenia genotypes into the following three clusters: one cluster comprised the 16 genotypes originating from Australia, one included the 16 genotypes originating from the USA, and the third cluster contained the four reference cultivars. In other words, there was a clear demarcation of the genotypes investigated according to their geographical origin. In addition, the gardenia genotypes were evaluated for their morphological and chemical characteristics. Thus, flower- and leaf-related traits with ornamental value were measured, while the volatile compounds of flower extracts were identified with GC-MS analysis. Genotype 29-5 was selected for its acceptable morphological traits and genotype 51-8 for its rich volatile compounds. The major volatile compounds responsible for the floral aroma of the various gardenia genotypes examined were α-farnesene, benzyl tiglate, cis-3-hexenyltiglate, jasminelactone and linalool.