Global Journal of Science Frontier Research, D: Agriculture and Veterinary, Volume 22 Issue 1

easily colonized by the mycorrhizal fungus, and produce many roots in a relatively short time (45-60 days) (Siqueira Martins et al ., 2017). The association established by AMF is not specific, which allows the same fungus to colonizes different plant species to generate symbiosis (Aguilar- Ulloa et al ., 2016). Also, there is a preference that certain AMF colonize and spread better in certain plant species (Covacevich and Echeverría, 2010). Furthermore, using the same fungal species is probably not optimal for all crops. For this reason, it is convenient to evaluate the MVA in each trap crop species. Because the interactions between different VMAs with soil microorganisms are complex, it is necessary to determine their behavior in the field under the growth conditions of each crop. The use of native MVA is recommended due to its adaptation to prevailing conditions, avoiding ecological risks associated with introducing exotic species (Sánchez de Prager, 2007). The objective was to determine the existence of mycorrhizal associations between autochthonous soil fungi and forage crops planted in the Central Valley of Catamarca and to evaluate the biological aspects of the interactions found. II. M aterials and M ethods Colonization of mycorrhizae in plant roots of six commonly cultivated forage species in the region was studied. The sowings were carried out in the locality of Miraflores, Department of Capayán, in the Central Valley of Catamarca, in plots of native forest or with agricultural history without application of mycorrhizal fungi. The species evaluated were: clover ( Melilotus officinalis L.), oats ( Avena sativa L.), barley ( Hordeum vulgare L.), rye ( Secale cereale L.), Gatton panic ( Panicum maximum Jacq.), and buffel grass ( Cenchrus ciliaris L.). In the laboratory, the roots of each of the collected plants were extracted and washed with running water. The thinnest were selected, those that were clarified and stained following the methodology of Phillips and Hayman (1970) to determine fungal colonization and detection of mycorrhizal structures. Staining was performed with Gueguén's triple dye solution, allowing fungi to stain proteins blue simultaneously, starch violet, fats red (Sarasola and Rocca, 1975), and glycogen in mahogany (Verna and Herrero, 1952). In each specimen, the percentage of fungal colonization by MVA and the percentages of the content of arbuscules (A) and vesicles (V) were quantified by the line intersection method of Giovannetti and Mosse (1980), and the frequency of appearance of A and V (Covacevich et al ., 2001). For each specimen, 15 segments of the colored roots were taken, and distributed randomly on a grid slide. By means of microscopic observation (10x and 40x), the presence- absence of mycorrhizal structures (A and V) was recorded in the horizontal and vertical intersections between roots and grid lines. Three repetitions of each species were performed, quantifying at least 100 intersections per preparation to later calculate the frequency of mycorrhizal infection, according to Giovannetti and Mosse (1980). MGiovannetti (%) = No. SI x 100 / No. SO Where: SI: number of infected segments (hyphae + arbuscules + vesicles) and SO: numberof total segments observed (hyphae + arbuscules + vesicles + no infection). Also, the percentage of hyphae of dark septateendophytes (ESO) and the percentage of microsclerotia were recorded. III. R esults and D iscussion In the six analyzed forage species, typical structures of endomycorrhizal fungi of the MVA type (hyphae, arbuscules, and vesicles), and of ESO fungi (with septate, melanized hyphae, and numerous microsclerotia) were observed. In all species there were continuous thin and thick hyphae, with intracellular and intercellular growth and some of them with lipids in a rosary inside. In clover, arbuscular distributed throughout the bark were observed, involved in the bidirectional transfer of nutrients (Smith and Read, 1997). Numerous vesicles of diverse morphology (spherical, oval, tapered) were also observed in this legume, so it is inferred that the roots are colonized by various species or genera of native HMVA. Vesicles with light blue (saccule) and red (single or multiple globules) colorations were observed. These structures are related to the carbon storage of in the form of lipids and fatty acids. For this reason, vesicles are defined as reserve organs of the fungal symbiont (Sieverding, 1983). A high level of fungal colonization was determined in the six forage plants, obtaining the highest values of mycorrhizal colonization (MC) in clover and barley roots (Table 1). The highest frequency of appearance of arbuscules (FAA) was observed in clover, while the lowest number of arbuscules was determined in oats. The highest frequency of vesicle appearance (FAV) was also observed in clover, with average values of 20% (Table 1). These results coincide with the statements of Covacevich and Echeverría (2010) that indicate that there is a preference for certain AMF to better colonize certain plant species.The more signicant colonization in clover is explained by the fact that Rhizobios-arbuscular mycorrhizae (AM) associations occur in legumes that act synergistically in infection, mineral nutrition, and plant growth (Fitter & Garbaye, 1994; Barea, 1997). The main effect of AM in © 2022 Global Journals 1 Year 2022 2 Global Journal of Science Frontier Research Volume XXII Issue ersion I VI ( D ) Native Mycorrhizh-Forming Fungi Associated with Cultivated Forage Plants in the Central Valley of Catamarca, Argentina