Application of arbuscular mycorrhizal fungi on the production of cut flower roses under commercial-like conditions

The objective of this work was to study the influence of two arbuscular mycorrhizal fungi (AMF) —Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe, and G. intraradices (Schenck & Smith)— on cut flower yield of rose ( Rosa hybrida L. cv. Grand Gala) under commercial-like greenhouse conditions. Flower production was positively influenced by G. mosseae inoculation. Both inocula tested caused low levels of mycorrhizal root colonization, with higher percentages in Rosa associated with G. mosseae. Significant improvement of plant biomass, leaf nutritional status or flower quality was not detected in inoculated plants probably due to the low symbiosis establishment. However, G. mosseae reduced by one month the time needed for 80% of the plants to flower and slightly increased number of cut flowers relative to non-mycorrhizal controls on the fourth, sixth and eighth months after transplanting. It is suggested that an altered carbohydrate metabolism could contribute to this positive effect. Low colonization of rose roots supports the idea that more effort is required to ensure successful application of AMF in ornamental production systems. Additional key words: Floriculture; Glomus intraradices; Glomus mosseae; phosphorus; Rosa hybrida. Resumen