**2. Global context**

The predominant plantation system in the subtropical environment is that developed by California, USA during the 20th century, it was adopted and/or adapted with certain variations in other countries from the equator to 42°latitude in both hemispheres [7]. Its technological support was the disinfection of soils with methyl-bromide + chloropicrin to eliminate soil diseases [8], the development of cultivars with high productivity and sensory quality of the fruit [9], and the optimization of the technological package for cultivation, fertigation, pest, disease and weed management practices [10]. The reproducibility of the previous production model, and the adoption of the macro-tunnel, located in Spain, Mexico, and other Mediterranean countries, among the largest producers of fresh strawberries.

When the use of methyl bromide ended in 2005 and 2015 in developed and developing countries, respectively, ended the relatively simple Era to eradicate biotic agents from the soil, since to date substitutes or alternatives are being investigated to replace it, being chemical, physical, microbiological agents, or a combination of them, that exerts action on a wide spectrum of biological entities [2].

#### *The Genetic Diversity of Strawberry Species, the Underutilized Gene Pool and the Need… DOI: http://dx.doi.org/10.5772/intechopen.102962*

Strawberries are grown in a wide variety of environments. In terms of latitude, it can be said that, from the equator to the polar zone [11], mainly in the northern hemisphere. Regarding altitude, from sea level to altitudes above 2000 meters above sea level [12]. These macroenvironments, with their different photoperiod, temperature, and rainfall regimes, as well as different pH and soil texture, are the genesis of an infinite series of microenvironments, and give rise to the so-called geographical and regional adaptation, a situation that affects cultivars. They can be adapted to a better or lesser degree to a certain environment [11].

The strawberry industry is experiencing a continuous varietal change. Except for China, where cultivars from Japan predominate [7], in the nine main strawberry producing countries, perhaps no more than 15 cultivars, generated by the Universities of California and Florida and, a few others from private companies are used. However, these genotypes share a close relationship since they descend from common or related parentals. Modern cultivars stand out for their productive qualities, good adaptation, and high sensory quality. The risky facet is associated with genetic uniformity and genetic erosion for traits that can confer tolerance and adaptation to biotic and abiotic factors, and their clonal spread, which is a risk of transmission of infectious agents.

The genetic vulnerability was shown since the end of the last century, both for nuclear genes [13] and for the cytoplasm [14] and becomes more valid in contemporary times, before the first signs of the globalization of phytosanitary problems of strawberry. During the twentieth century, biotic problems were caused by 20 pests, 108 diseases, and eight nematodes, in addition to five abiotic agents [15]. It was anticipated that others could arise [16] and this was the case in this century with *Drosophila suzukii* [17], and the diseases caused by *Colletotrichum* spp. [18], *Fusarium oxysporum* f. sp. *fragariae*, *Macrophomina phaseolina*, and probably *Neopestalotiopsis* spp.
