Agricultural and Food Biotechnologies of Olea europaea and Stone Fruits

In this chapter the main botanical and agricultural aspects of the olive (Olea europaea L.) are summarized. In the section on botany, the functional parts and the biological cycle of the plant are described; while in the agricultural one, the environmental and physiological demands of the plant, and the most diffused training shapes are reported. In the agronomical section are described the main soil practices, with the aim of to preserve and improve ground conditions, such as setups, tillages, weeding, grassing; and trees practices, regarding plant growth and yield, such as irrigation, fertilization, and pruning. Then, a section regarding harvesting systems in different olive orchard typologies, and the control of olive pests and diseases in traditional, sustainable and organic farming, completes this chapter.

The olive (Olea europaea L.) is one of the most ancient cultivated fruit trees. Olive trees are considered to be one of the most widely grown fruit crops in the countries of the Mediterranean basin. Olive products, such as olive oil, table olives and olive pastes are staple foods of the Mediterranean diet due to their benefits for human health, as well as other applications such as in cosmetics.

More than 2600 olive plant cultivars have been described using morphological analysis, although many of them might be synonyms, homonyms, ecotypes or the result of crosses between neighbouring olive cultivars. The high number of olive cultivars causes a considerable problem in germplasm collection management and both the traceability and authenticity of olive oils produced, once there is an uncertainty about its correct olive cultivar denomination. Until recent years, cultivar identification was only based on morphological and agronomic traits. However, recognition of olive cultivars based on phenotypic characters was revealed to be problematic, especially in the early stages of tree development. In recent years molecular markers have been applied in olive germplasm to identify cultivars and to determine the relationships between cultivars.

The increasing openness of genetic markers in olive trees allows detailed studies and evaluations of genetic diversity. This will provide a view of what has been attained and what still needs to be done in order to better understand this crop that has lived for centuries and still remains to be fully discovered and understood.

Although current breeding strategies can now benefit from the availability of new polymorphic genetic markers, the characterization of olive germplasm is still far from complete.

A wider gene characterization of loci related to the quality of plant products and adaptive mechanisms could provide new information and tools to support Marker Assisted Selection (MAS) strategies and new biotechnological approaches to develop suitable growing techniques and increase productivity and product quality of this species which is unique in its kind.

The technological aspects related to table olives and olive oil are summarized and discussed in this chapter. There are three main trade preparations of table olives: Spanish-style olives, Californian-style olives and naturally black or turning colour olives. There are also many other traditional table olive recipes that are less known in the international market but which are specially linked with a given territory as the product of natural and cultural resources. Some traditional process will also be described and the use of starter cultures in table olive fermentation will also be discussed. Interest in the development of and use of starters for table olive fermentation is increasing as appropriate bacterial inoculation can help to achieve a more controlled process, reduce processing time and improve the organoleptic and hygienic quality of the final product. Suitable hygienic conditions to adopt during olive processing and their alterations are then considered. Moreover, the traditional and the most innovative technologies for mechanical olive oil extraction are described with particular attention given to the discussion of technical aspects and analysis of the repercussions of each processing step on the most important quality markers are subsequently discussed.

Prunus is a genus of about 230 species, distributed primarily in north temperate regions. Prunus has been historically divided into a number of genera by various botanists. Three subgenera correspond to broad categories of stone fruits. Main domesticated species are peach, apricot, cherry and plum. Different characters have been used to uniquely identify genotypes and cultivars. In the present chapter the main pomological and phenological characteristics are presented. Features and ripening dates are described for 72 peach cultivars: 19 with white flesh, 28 with yellow flesh, 13 canning peaches and 12 with flat shape. Forty-one different nectarines, 46 apricots, 48 cherries and 18 Japanese and 5 European plums cultivars are also described. A second part of the chapter is also devoted to the description of the physiological phenomena related to production and to the main agricultural techniques and best practices for orchard management.

Plant breeding has made remarkable progress in recent years and many agronomically important characters such as yield, quality and resistance to biotic and abiotic threats have been improved in many crop species. The use of molecular markers and, more recently, the availability of sequenced genomes are fostering the characterization and isolation of genes involved in key processes related to these traits in many species. This is in turn giving the opportunity to apply marker assisted selection (MAS) enabling the production of improved varieties in less time and at reduced costs compared to traditional breeding strategies. In Prunus spp, many linkage maps have been produced and several traits have been genetically localized leading, in a few cases, to the cloning of the genes underlying important traits. More recently, peach (Prunus persica) was chosen as the model species of the Prunus genus and its genomic sequence has been obtained (Peach v1.0). This will offer new opportunities to genomic-assisted breeding in all stone fruits. In the present chapter, the latest achievements in the genetics and genomics of the Prunus species are discussed together with the main relevant breeding outcomes.

Apricots, cherries, peaches, nectarines, and plums (all belonging to genus Prunus), are commonly referred to as “stone fruits” due to the fact that their seed is enclosed in a hard (stone-like) endocarp. Stone fruits are produced in almost all agroecological regions of the world, with commercial production reported in over 80 countries. All stone fruits are healthy and nutritious, being low in calories and rich in many nutrients and bioactive compounds (antioxidants). Stone fruits, except for sour cherries, are enjoyed fresh due to their rich flavors and aromas. Stone fruits are processed into a variety of products, e.g., canned, frozen, dried, puree, juice, concentrate, jam, and jelly. This chapter provides an overview of stone fruits production, postharvest physiology and storage, processing/products, nutritional profile, and health benefits.