Pré-enraizamento de mudas de mandioquinha-salsa em diferentes bandejas e substratos com fungos micorrízicos arbusculares

Abstract

The objective of the work was to study the root colonization by arbuscular micorrhizal fungi (AMF) during the development of Peruvian carrot rhizomes (Arracacia xanthorrhiza Bancroft). The treatments consisted of two substrates and two polystyrene trays sizes. A common substrate constituted of 30% of organic compost, 30% of loamy soil and 30% of sand, and a commercial substrate "Plantmax® Hortaliças"; and polystyrene trays sizes of 128 cells/tray (38 cm3 per cell) and 200 cells/tray (18 cm3 per cell) were used. A mixed inoculation of AMF, with soil inoculum composed by the species Gigaspora margarita and Glomus clarum was done. In both substrates a restricted response of inoculation of AMF, occurred low root colonization, was low ranging from 0.63 to 2.14% in the commercial substrate and 7.93 to 15.09% in the common substrate. The common substrate did not present desirable physical characteristics (aeration and drainage) for a good development of the Peruvian carrot roots during the pre-rooting phase. The commercial substrate resulted in larger averages for root area and length in all the samplings. Root area varied from 21.50 cm2 with 30 days after planting (DAP) to 68.22 cm2 with 60 DAP, while root length varied from 2.64 m with 30 DAP to 12.64 m with 60 DAP. The tray of 200 cells (18 cm3 cell/tray) did not adapt for the production of Peruvian carrot seedlings.