Habilidad competitiva entre plantas de festuca alta libres e infectadas con hongo endófito bajo cosecha.: Habilidad competitiva de festuca alta con endófito
Given the increased incidence of the endophyte Epichloë coenophiala in tall fescue pastures and the consequent risk of fescue toxicosis, it is important to understand the role played by competition between infected (E+) and endophyte-free (E-) plants in interaction with defoliation, in increasing the frequency of E+ on E-. A competition experiment with substitution design was conducted in field pots. Four genotypes E+ and E- of tall fescue were used (removal with fungicide and cloning). The obtained E- and E+ clones were grown as E+E+ and E-E- monocultures, or 1: 1 E+E- mixtures, at a constant density of 8 plants per pot (2 per genotype) and were combined with two levels of defoliation (without and with mechanical cut). Aerial biomass cuts were made every 2 weeks at 3 cm from the ground level. Endophyte-fescue symbiosis did not translate into higher aerial biomass of E+E+ monocultures compared to E-E-, regardless of cut treatment. In the control treatment without defoliation, the E-E- monocultures produced higher aerial biomass than the E+E+, suggesting a net cost of the symbiotic association. When both phenotypes grew in 1: 1 mixtures, E+ plants behaved as dominant, according to the estimated competition and aggressivity indices. Contrary to expectations, neither the periodic cutting of aerial biomass nor the provision of growth conditions without resource restrictions, neutralized an apparently beneficial effect of the symbiosis on E+ plants, growing in a 1: 1 mixture with E- plants. The incidence of infection in E+E- mixtures would tend to increase, at least under favourable conditions for plant growth, even in absence of other herbivores which could be deterred by E+ plants.
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociacion Latinoamericana de Produccion Animal
2021
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| Online Access: | https://ojs.alpa.uy/index.php/ojs_files/article/view/2831 |
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