Raul de la Rosa

Spanish National Research Council | CSIC · Department of Plant Breeding

Hedgerow cultivation systems have revolutionized olive growing in recent years because of the mechanization of harvesting. Initially applied under irrigated conditions, its use has now extended to rainfed cultivation. However, there is limited information on the behavior of olive cultivars in hedgerow growing systems under rainfed conditions, which...

The hedgerow growing system is prevalent in new olive orchards worldwide due to its fully mechanized harvesting. Several works have been published to compare cultivars planted in this system, focusing on productivity and oil composition. However, little research has been conducted on the long-term evaluation of cultivars’ growth habits when trained...

The oxidative stability index (OSI) and fatty acid (FA) composition of extra virgin olive oils (EVOOs) are key parameters in the characterization of new varieties in breeding programs. Their determination through traditional methods (Rancimat and gas chromatography, respectively) is expensive and time-consuming. Therefore, there is a need to develo...

In Spain, several local studies have highlighted the likely presence of unknown olive cultivars distinct from the approximately 260 ones previously described in the literature. Furthermore, recent advancements in identification techniques have significantly enhanced in terms of efficacy and precision. This scenario motivated a new nationwide prospe...

Verticillium wilt of olive (VWO) is one of the most widespread and devastating olive diseases in the world. Harnessing host resistance to the causative agent is considered one of the most important measures within an integrated control strategy of the disease. Aiming to understand the mechanisms underlying olive resistance to VWO, the metabolic pro...

Extra virgin olive oil (EVOO) is renowned for its numerous minor compounds, particularly phenols, which contribute to its health-promoting properties and commercial quality. The phenolic composition of EVOO largely relies on the initial phenolic content of the olive fruits, which represents, therefore, an important trait to be considered in olive b...

Olive is one of the most cultivated species in the Mediterranean Basin and beyond. Despite being extensively studied for its commercial relevance, the origin of cultivated olive and the history of its domestication remain open questions. Here, we present a genealogical and kinship relationships analysis by mean of chloroplast and nuclear markers of...

The large amount of olive cultivars conserved in germplasm banks can be used to overcome some of the challenges faced by the olive growing industry, including climate warming. One effect of climate warming in olive is the difficulty to fulfill the chilling requirements for flowering due to mild winter temperatures. In the present work, we evaluate...

The olive wide genetic variability can be used to overcome some of the challenges faced by olive growing, including climate warming. One effect of climate warming in olive is the difficulty to fulfill the chilling requirements for flowering due to high winter temperatures. In the present work, we evaluate seven olive cultivars for their adaptation...

The fruit size of a cultivated olive tree is consistently larger than its corresponding wild relatives because fruit size is one of the main traits associated with olive tree domestication. Additionally, large fruit size is one of the main objectives of modern olive breeding programs. However, as the long juvenile period is one main hindrance in cl...

Olea europaea subsp. cuspidata has a relatively low commercial value due to the low size and pulp to stone ratio of its drupes compared to commercial olive cultivars. Nevertheless, this subspecies could represent a valid source of useful traits for olive breeding. In the current work, the drupe metabolic composition (secoiridoids, flavonoids, simpl...

Despite the importance of flowering for fruit formation, it has been considered very little in breeding programs involving fruit species, including olives. We evaluated the principal morphological flower-quality components in the olive cultivars, ‘Arbequina’ and ‘Picual’, and in the progenies of their crosses. Wide ranges of variation were obtained...

The long juvenile period in olive (Olea europaea L.) delays the evaluation of characters of interest and prolongs the selection of new cultivars in the breeding programs. Therefore, it is important to use accurate selection criteria and appropriate selection pressure to make an effective identification of the superior genotypes and to identify whic...

Olive, the emblematic Mediterranean fruit crop, owns a great varietal diversity, which is maintained in ex situ field collections, such as the World Olive Germplasm Bank of Córdoba (WOGBC), Spain. Accurate identification of WOGBC, one of the world’s largest collections, is essential for efficient management and use of olive germplasm. The present s...

Hedgerow orchard is an olive growing system where trees are planted at a super high-density higher than 20-fold (i.e., 1200–2500 trees ha ⁻¹ ) compared to the traditional density of olive orchards (usually 50 to 160 trees ha ⁻¹ ). It is dominating a great proportion of new plantations because harvesting can be fully mechanized, it is early bearing...

Some adaptation measures in response to the severe impacts of climate change on Mediterranean olive orchards were evaluated under a wide range of weather conditions. For this task, a decision support system for improving resources management by the integration of the AdaptaOlive simulation model, perturbed climate and impact and adaptation response...

In the present work, we compared the phenol content and composition of fruit from the ‘Arbequina’ cultivar in four Mediterranean (in Andalucía, Southern Iberian Peninsula) and two Sub-Tropical (Canary Islands) locations throughout the harvest period. Two Mediterranean and two Sub-Tropical locations were maintained with drip irrigation, while the re...

Since 2015, a large-scale olive screening program for identifying sources of resistance to Xylella fastidiosa subsp. pauca ST53 (Xfp) was started under natural (field) and controlled conditions (greenhouse, GH) in Apulia (southern Italy). Approx. 100 genotypes including olive cultivars (from 15 different olive-growing countries) and breeding select...

The purpose of this study was to evaluate the relationship between two types of vigor and architectural parameters (quantitative and qualitative) and the duration of juvenile period in olive and to test the effectiveness of three different strategies for an early elimination of seedlings with long juvenile period. Architectural parameters were eval...

Background Olive orchards are threatened by a wide range of pathogens. Of these, Verticillium dahliae has been in the spotlight for its high incidence, the difficulty to control it and the few cultivars that has increased tolerance to the pathogen. Disease resistance not only depends on detection of pathogen invasion and induction of responses by t...

Olive is a woody crop extended over 10 Mha around the world (FAOSTAT, 2019), being Spain the country with the largest area (2.7 Mha). Andalusia is located in the South of Spain, with 1.6 Mha cultivated with olive trees, most of them (around 90%) dedicated to olive oil production (MAPA, 2020). This region is characterized by a great diversity of wea...

Genetic resistance is the most recommended measure to control verticillium wilt in olive (VWO), a vascular disease caused by the soil-borne fungus Verticillium dahliae, which has promoted in recent years the development of olive breeding programs aiming at obtaining new resistant and highly yielding cultivars. Screening has been commonly performed...

The characterization of tree canopy traits represents a key step to identify potential cultivars adaptable to a specific growing system. Developing methodologies to rapidly evaluate canopy traits allows to classify cultivars in germplasm banks and facilitates selections in breeding programs. In the present work, the ability of low-cost unmanned aer...

Olive flowering phenology is highly affected by climatic conditions. Phenological models have been developed to forecast flowering date on olive mainly based on temperature. These models have used flowering datasets collected from trees growing under Mediterranean climatic conditions. In most of the cases, in those conditions, chilling requirements...

Several factors affect the volatile fraction of extra virgin olive oil (EVOO). In this work, three advanced breeding selections and “Picual” cultivar are evaluated in comparative fields under different climatic conditions, to test and quantify the effect of genetic (G) and environmental (E) factors and their interaction (GxE). Significant differenc...

Olive oil is highly valued by its nutritious and healthy function mainly due to its chemical composition. Oil chemical components are highly influenced by the cultivar and the environment, resulting in some cases in levels out of the limits set by the International Olive Council. In the present research, we used a multi-environment trial with five...

Extra virgin olive oil (EVOO) chemical composition is characterized by high content of monounsaturated fatty acids and minor compounds including phenols, sterols, tocopherols, squalene and volatile compounds. These components are related to EVOO quality in terms of healthy properties, shelf life alteration due to susceptibility to oxidative degener...

Background: The species Olea europaea includes cultivated varieties (subsp. europaea var. europaea), wild plants (subsp. europaea var. sylvestris), and five other subspecies spread over almost all continents. Single nucleotide polymorphisms in the expressed sequence tag able to underline intra-species differentiation are not yet identified, beyond...

Cultivated olive (Olea europaea subsp. europaea var. europaea) is one of the most ancient cultivated fruit trees with a huge genetic heritage. More than 1200 olive cultivars are conserved in olive germplasm collections around the world. A core collection of 36 accessions was defined in the largest world olive germplasm bank of IFAPA based on geneti...

The control of the olive tree vigor is a critical factor to ensure adequate production and longevity of high-density olive cultivation. To deal with this problem, we intend to take advantage of the genetic variability present in the wild subspecies of Olea europaea to identify genotypes of reduced vigor with optimal adaptability to diverse soils an...

The primary domestication of olive (Olea europaea L.) in the Levant dates back to the Neolithic period, around 6,000–5,500 BC, as some archeological remains attest. Cultivated olive trees are reproduced clonally, with sexual crosses being the sporadic events that drive the development of new varieties. In order to determine the genomic changes whic...

Aim of study: Crop phenology is a critical component in the identification of impacts of climate change. Then, the assessment of germplasm collections provides relevant information for cultivar selection and breeding related to phenology, being the base for identifying adaptation strategies to climate change. Area of study: The World Olive Germpla...

Olive crop constitutes the main economic and social crop in numerous areas of the Mediterranean basin. However, recently there is a growing concern about the future sustainability of this crop due to the limited profit and the increasing frequency of climatic hazards as droughts and heat events. The tool AdaptaOlive integrates different simplified...

Olive is a long-living perennial species with a wide geographical distribution, showing a large genetic and phenotypic variation in its growing area. There is an urgent need to uncover how olive phenotypic traits and plasticity can change regardless of the genetic background. A two-year study was conducted, based on the analysis of fruit and oil tr...

Flowering is one of the most critical processes in the reproductive phenology in fruit trees including olive. Under Mediterranean climate, olive flowering period normally occurs from early to late spring. Therefore, flowering time could be affected by environmental conditions such as water availability and temperature, thus influencing flower quali...

Olive (Olea europaea L.) is one of the most important fruit crops in the Mediterranean Basin, because it occupies significant acreage in these countries and often has important cultural heritage and landscape value. This crop can be infected by several Meloidogyne species (M. javanica, M. arenaria, and M. incognita, among others), and only a few cu...

Virgin olive oil (VOO) is the main source of lipids in the Mediterranean diet and one of the main contributors to its proven protection against diseases associated with chronic inflammation states. This oil is rich in antioxidant compounds such as tocopherols, which together constitute the vitamin E stock of the oil. The purpose of the present work...

The pattern of olive oil accumulation is of paramount importance in olive because its influence in determining final oil yield and optimal harvesting date. In this work, we have evaluated the genetic and environment influence on the olive oil accumulation pattern. For that purpose, a set of cultivars and breeding selections planted in a multi-envir...

Olive is an evergreen tree species that is cultivated in 10.8 million hectares all over the world, being more than 2.5 million hectares planted in Spain (FAO, 2017). Andalusia, in Southern Spain, is the main region of the world both by surface and production. This region is characterized by a great diversity of soil types and weather conditions. Fo...

Olive (Olea europea L.) is one of the most important crops along the Mediterranean Basin, given its social and economical relevance. Cultivated among centuries, olive tree is a priceless source for a large number of products, such as olives, wood, biomass as energy source and one of the most well-known edible oils in the world, the olive oil. There...

Germplasm collections are basic tools for conservation, characterization, and efficient use of olive genetic resources. The identification of the olive cultivars maintained in the collections is an important ongoing task which has been performed by both, morphological and molecular markers. In the present study, based on the sequencing results of p...

The NJ dendrogram including all cultivated plant material analyzed in the study.

AdaptaOlive is a simplified physically-based model that has been developed to assess the behavior of olive under future climate conditions in Andalusia, southern Spain. The integration of different approaches based on experimental data from previous studies, combined with weather data from 11 climate models, is aimed at overcoming the high degree o...

A wide genetic diversity has been reported for wild olives, which could be particularly interesting for the introgression of some agronomic traits and resistance to biotic and abiotic stresses in breeding programs. However, the introgression of some beneficial wild traits may be paralleled by negative effects on some other important agronomic and q...

Olive growing is mainly based on traditional varieties selected by the growers across the centuries. The few attempts so far reported to obtain new varieties by systematic breeding have been mainly focused on improving the olive adaptation to different growing systems, the productivity and the oil content. However, the improvement of oil quality ha...

In olive, both discontinuous canopy (open vase configuration) and continuous canopy (hedgerow) systems are used in commercial planting. Reliable and cost effective plant architecture characterization is necessary to test the suitability of cultivars to specific growing systems, particularly in olive breeding programs where a large number of genotyp...

Due to the severe increase projected in future temperatures and the great economic and social importance of olive growing for vast agricultural areas in the Mediterranean Basin, accurate climate change impact assessment on olive orchards is required. The aim of this study is to assess the flowering date and the impact of mean and extreme temperatur...

Background and aims: Wild olive (Olea europaea subsp. europaea var. sylvestris) is important from an economic and ecological point of view. The effects of anthropogenic activities may lead to the genetic erosion of its genetic patrimony, which has high value for breeding programmes. In particular, the consequences of the introgression from cultiva...

Olive tree is a long-living woody species with similar genomic and phenotypic constraints to other perennial fruit crops. However, compared to apple, grape, and peach, genomic investigations for designing innovative breeding strategies are still limited to only preliminary research in this species. In this chapter, we aim to describe the studies on...

Fatty acids are the main components of the olive oil and their composition has a critical influence on the oil quality. However, oil quality evaluation has not been frequently included in the selection of new bred cultivars. This can be due to the difficulties in analyzing oil quality in large set of genotypes and also to the long juvenile period o...