IANNONE Leopoldo Javier
congresos y reuniones científicas
Effect of Ustilago bullata and Epichloë sp. on biomass and seed production by Bromus auleticus
VIGNALE, M.V.; PINGET, A.D.; DE BATTISTA, J.P.; RE, A.; NOVAS, M.V.; IANNONE L.J
Congreso; 5TH International Symposium of Forage Breeding; 2015
Bromus auleticus is one of the most promising C3 native forage and is usually infected by Epichloë spp. and Ustilago bullata. Epichloë colonizes asymptomatically aerial structures of this plant to reach the ovary in order to be disseminated with the seed. Ustilago bullata (Ustilaginales) infects the plants systemically and replaces the ovary with teliospores producing sterility (smut). Thus, in co-infected plants the smut and the endophyte compete for the ovary in order to be disseminated. Here we evaluated, in a field experiment, the effect of U. bullata infection on biomass and seed production of B. auleticus and the effect of an Epichloë sp. endophyte on the susceptibility of B. auleticus to smut disease. To achieve this, endophyte infected (E+) and endophyte free (E-) seeds were inoculated (S+) or not (S-) with U. bullata teliospores (0.16 mg of viable teliospores/seed). A completely randomized design with two factors, endophyte status (E+ vs. E-) and smut inoculation (S+) and (S-) and four replicates was established in the field. Each replicate consisted of parcels with 3 lines (2 m long) sowed with 5 gr. of seeds/line. The experiment was set in June 2012, in April 2013 plants were cut at 7 cm from the soil, the harvested biomass was weighed and plants were allowed to re-grow. In December 2013 the proportion of culms with smut symptoms and the amount of seeds produced were evaluated. During the first year E+ plants produced 23% more biomass than E- plants. Smut inoculation reduced biomass production, 15% in E+ and 26% in E-. Endophyte infected plants produced in average 43% more culms than E- plants and the smut did not significantly affect culms production in E+ or E- plants. The 38% of the culms of E- plants were affected by the disease whereas only a 1.4% was affected among the E+ ones. E+S+ plants produced the highest amount of seeds and E-S- plants produced the lowest amount (54% less than E+S+ and a 35% less than its E-S- counterparts). These results show the importance of the management of the symbiosis between Epichloë and B. auleticus in the breeding of this native grass.