**3. Diversity of arbuscular mycorrhizal fungi from moroccan saffron plantations areas**

The knowledge of the current richness of Glomale an AM fungi (Glomerales; Glomeromycota) and biological diversity associated with plants grown in adverse environments could be necessary to expand the cultivated area and increase the performance of arable lands.

AMF diversity has been scarcely studied in the Taliouine-Taznakht region where saffron cultivation is exclusively concentrated [29].

This diversity was unveiled by direct spore isolation and morphological characterization of rhizospheric soil and roots samples from different sites in the main saffron production region. A variety of endomycorrhizal fungi has been noted in the rhizosphere of *C. sativus* grown in the Taliouine region (Tinfat) (**Figure 4**) [30]. These authors have detected 36 morphologically distinctive AMF species that were directly retrieved from field samples. All the encountered species in the different studied sites belong to six genera: *Glomus* (14 species), *Acaulospora* (10 species), *Scutellospora* (6 species), *Gigaspora* (2 species), *Pacispora* (2 species), and *Entrophospora* (1 species). The genus *Glomus* was the most dominant, it occurred in all studied sites with a proportion of distribution that varies between 8.33% and 30.56%.

A low number of AMF species have been reported by Ourras et al. [24]. Chamkhi et al. [31] detected 11 species of AMF spores among which *Funneliformis* and *Rhizoglomus* species were the most abundant (>35%). Yang et al. [32] reported that AMF soil community evolved in the function of environmental conditions. Another factor affects AMF survival and community composition in association with the saffron crop.

#### **3.1 Age of plantation**

Age of plantation seemed to be affected the richness of AM fungi, spore density and root colonization rates [12, 24, 31]. Indeed, the greatest richness of AM fungi was registered in the site at 4 years of successive exploitation by saffron (24 species),

**Figure 4.**

*Some indigenous endomycorrhizal fungals pecies isolated from the rhizosphere of* Crocus sativus *grown in Taliouine areas.*

followed by the site at 6 years of occupation by saffron (21 species), while the lowest number of species was recorded at the sites of two, three and 10 years of soil use by saffron [33]. According to Yu et al. [34], stand age significantly changed the structure of the AM fungal community. The increase of spore density with field age has been cited in previous literature reviews [35, 36]. Rengifo-Del Aguila et al. [37] found that intra-radical colonization and AM fungal phylogenetic diversity increased with plantation age, while AM fungal richness was still constant across time but a significant compositional turnover was detected.

Many studies have demonstrated that the shift in the AM fungal community over ecological succession is associated with variations in soil properties induced by stand age, such as soil texture [38], pH [39], and nutrient availability [40]. Krüger et al. [41] pertain that P has become increasingly limited in old soils as the amount and availability of P declines over time. The changes in soil's chemical and physical properties can play an important role in decreasing saffron yields even after 6 years of cultivation [42].
