Identificación de cepas autóctonas de micorrizas bajo sistemas de pastoreo en Valverde Mao, República Dominicana

The presence of mycorrhizal-forming fungi associated with grass collected in agroecosystems of 12 cattle farms in the province of Valverde, Dominican Republic and their colonization capacity was investigated. Six samples were taken per farm from rhizospheric soils to morphologically identify arbuscular mycorrhizal fungi and quantify the number of spores per sample. Nine morphotypes were identified compared with the results of other investigations: Glomus sp., Glomus microaggregatum BEG56, Acaulospora sp, Scutellaspora avannicola, Acaulospora denticulata Sieverd. & S. Toro, Glomus geosparum, Glomus dimorphicum Boyetchko & J.P. Tewari, Scutellasporas sp and Paraglomus sp., Glomus sp being the most frequent genus in all the samples analyzed. The highest number of mycorrhizal spores was found in farms 8 and 9. A physical-chemical analysis was carried out on the soils under study to determine the mycorrhizal pH-nutrient relationship, showing a positive correlation with the number of spores found in the soil., organic matter, phosphorus, calcium, sodium and magnesium. In the study of roots of these grasses, the type of characteristic structure of arbuscular mycorrhizae was found vesicles, hypha and mycelia. Using molecular techniques (PCR) carried out on the roots, strains belonging to the Glomeromycota group were identified from farms 2, 5, 6, 7, 8, 9 and 12 and in a second test (PCR) the genus Glomus sp was identified in root samples, in which sample number 11 was positive, this being the first study in which arbuscular mycorrhizal fungi associated with roots and soil of the pastures present in the selected livestock farms are reported. These species are described, illustrated and cited for the first time for the Dominican Republic.